Renewable Energy Global Innovations features: Theoretical Analysis for The Centrifugal Effect On Premixed Flame Speed in A Closed Tube

Significance Statement

The effect of centrifugal acceleration on the mixed flame speed has over time been observed to be significantly important in both theoretical research and engineering application. Recently, empirical investigations on the novel inter-turbine burner engine and the Ramgen engine have shown that they possess significant benefits on performance, since they apply the concept of combustion in high centrifugal fields. Previous studies on centrifugal forces have revealed that high centrifugal acceleration possess significant strengthening effect on combustion. On the contrary, little exists on the adaptation, derivation and harnessing of this power in written academia.

Researchers led by professor Yong Huang at the Collaborative Innovation Center of Advanced Aero-Engine, National Key Laboratory of Science and Technology, School of Energy and Power Engineering, Beihang University described the effect of centrifugal acceleration, specifically high centrifugal acceleration of more than 200 times the gravitational acceleration, on the premixed flame speed in a rotating closed tube. Their main objective was to derive a theoretical predicted correlation which would describe the laminar premixed flame speed in a centrifugal field with the aid of directly solving simplified governing equations on 1-D steady adiabatic flame by theoretical analysis. Their research work is now published in International Journal of Hydrogen Energy.

The research team begun by employing the 1-D steady adiabatic flame model which was fixed. The team then obtained the premixed flame speed in a rotating closed tube after considering the amplification effect of the closed tube on the laminar premixed flame speed. The researchers then, using the predicted correlation, obtained the physical mechanisms of the premixed flame speed in a rotating closed tube.

The authors observed that the flame speed accelerated by the centrifugal force was nearly proportional to the square root of the centrifugal acceleration in the rotating closed tube. The team also noted that the theoretical prediction was also able to revealed that the flame speed in a rotating closed tube was determined by the initial temperature, the critical ignition temperature, the adiabatic flame temperature and the thicknesses of reaction zone. Eventually, the premixed flame speed in a rotating closed tube was seen to increase nearly linearly with the increasing of the initial temperature or square root of the thicknesses of reaction zone, or with decreasing of the critical ignition temperature or the adiabatic flame temperature.

Herein, a theoretical analysis to study the effect of centrifugal acceleration, especially high centrifugal acceleration, that is, more than 200 times the gravitational acceleration of earth, on the premixed flame speed has been successfully presented. More importantly, a theoretical predicted correlation has been proposed to describe the premixed flame speed in a rotating closed tube. The results of the theoretical prediction have been seen to agree well with the empirical data obtained by Lewis & Smith. The result of the study verifies that the flame speed accelerated by the centrifugal force is nearly proportional to the square root of the centrifugal acceleration.

About The Author

Dr. Yong Huang is the chief professor in the Department of thermal power engineering, School of Energy and Power Engineering, Beihang University, Beijing, China. He was granted Bachelor Degree from Tsinghua University in 1985. Then, he obtained Master Degree and Doctoral Degree in Beihang University. He did postdoctoral research in Hong Kong University of Science and Technology.

He is one of the top experts in the field of gas turbine combustion in China. In the past years, he has won the second prize of science & technology improvement by Ministry of Aviation Industry of PRC(1993), the third prize of science & technology improvement by Ministry of Aviation Industry of PRC(1993), the second prize of science & technology improvement by Ministry of National Defence(2004).

His main research interests include the mechanism and prediction of ignition and lean blowout in gas turbine combustors, mechanism of atomization and design of atomizers, performance prediction of low pollution combustors, flow field analysis in combustors, and multipoint lean direct injection combustors, etc.

He proposed the concept of Flame Volume(FV) model to improve the prediction of lean blowout limit derived by Lefebvre. This is an important breakthrough for gas turbine combustors in recent years. And he proposed the concept of flame mixing time (FMT) to estimate the NOx formation and obtain good agreement with the experimental data done by NASA that was ever wrongly predicted by other methods. Besides, he firstly proposed the concept of loss of rotational kinetic energy in pressure swirl atomizers due to liquid viscosity to predict the spray cone angle of pressure swirl atomizers. His course, combustion and combustor, is one of excellent courses in Beihang University. He has published more than 150 academic papers.

Contact: yhuang@buaa.edu.cn

About The Author

Dr. Lei Sun is a PhD candidate in the Department of thermal power engineering, School of Energy and Power Engineering, Beihang University, Beijing, China. He was granted Bachelor Degree from Beihang University in 2012. He was a visiting researcher in Hokkaido University, Japan in 2016.

He is experienced in mathematical modeling and theoretical analyses for physical phenomena. He has won the first prize of National Mathematics Competition for College Students(2011), the second prize of National Physics Competition for College Students(2010), the third prize in the Zhou Pei-Yuan Mechanics Competition for College Students(2011), etc. His research topics include the mechanism and prediction of lean blowout in gas turbine combustors, multipoint lean direct injection combustors, and mechanism of atomization, etc. He has published 8 academic papers.

Contact: sunlei1988@buaa.edu.cn

About The Author

Ms. Yingyi Ji is an engineer of gas turbine engine in Aero Engine Corporation of China. She was granted Bachelor Degree from Beihang University in 2013. She received her master degree in Aeronautical Engineering from Beihang University in 2016, researching on the centrifugal effect on premixed flame speed and the optimization design on diffuser of lean direct injection combustor.

Her recent research includes heat transfer of perforated plate, Oxygen-deficient Combustion in low speed gas flow.

Contact: jiyingyi0319@sina.com

Reference

Lei Sun, Yong Huang, Yingyi Ji. Theoretical analysis for the centrifugal effect on premixed flame speed in a closed tube. International Journal of Hydrogen Energy, volume 42(2017) pages 18658 – 18667.

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Renewable Energy Global Innovations features: Molecularly Imprinted Polymer Enables High-Efficiency Recognition and Trapping Lithium Polysulfides for Stable Lithium Sulfur Battery

Significance Statement

Molecularly imprinted polymers have in recent times been attracting widespread interest especially arising from their application in the development of tools for organic synthesis as a result of their high specificity, easy availability, stability and low cost. These synthetic polymers are fabricated by polymerizing polymerizable reagents in the presence of a template. More so, these molecularly imprinted polymers have the capability to selectively reorganize and bind target molecules with tailor made molecular recognition binding sites. With such binding capabilities, molecularly imprinted polymers have been widely applied in catalysis, analytical chemistry, water treatment, sensors and biochemistry field.

However, their potential can still be tapped by constructing different binding sites which would in turn yield new applications. Consequently, the mutual demand for clean energy from modern industries inclusive of military power supplies, civil transportation and stationary storage have placed urgent demands on the energy density of the battery. Lithium-sulfur batteries have been considered promising for powering portable electronics because they have an overwhelming advantage in energy density.

Prof. Chenglin Yan and colleagues from Soochow University in China proposed a breakthrough study on the adaptability of molecularly imprinted polymers to enable high efficiency recognition and trapping of lithium polysulfides for the development of stable lithium-sulfur battery. The researchers aimed at exploiting the ability of the molecularly imprinted polymers to recognize and target specific molecules. Their research work is now published in Nano Letters.

The researchers commenced their empirical procedure by preparing molecularly imprinted polymers with Lithium-Sulphur recognition characteristics by polymerization of acrylamide monomer molecular with tetraglyme catholyte as the target template. Polymerization by initiation at 70⁰C with azodiisobutyronitrile as the initiator was then effected. Eventually, the removal of template molecule by anhydrous dimethylformamide washing and cyclic voltammetry scans, that left featured binding sites in the polymer matrix was done.

The research team observed that the approached they used, permitted them achieve a high capacity retention of over 82% after just 400 cycles at one coulomb. They also noted that the UV/vis spectroscopy revealed low concentrations of tetraglyme catholyte in the electrolyte indicating that the molecularly imprinted polymers matrix has excellent ionic sieving ability to tetraglyme catholyte during electrochemical cycle. More so, the visual characterization gave direct evidence on the affinity and absorbability of molecularly imprinted polymers to tetraglyme catholyte, which was theoretically confirmed by density functional theory calculations.

Herein, a new strategy of using molecularly imprinted polymers as recognition sites for polysulfides in Lithium-Sulphur battery system so as to trap long chain polysulfides, has been brought forward. Acrylamide and tetraglyme catholyte molecule have been employed as functional monomer and template, respectively, for the construction of molecularly imprinted polymers material, which can constraint tetraglyme catholyte in the molecularly imprinted polymers matrix by rebinding the target molecules. Undoubtedly, the original design demonstrated here opens a new direction of the electrochemical application of molecularly imprinted polymers materials in Lithium−Sulphur batteries.

About The Author

Chenglin Yan is a full professor at Soochow University and executive director of key laboratory of advanced carbon materials and wearable energy technology in Suzhou, China. He received his PhD from Dalian University of Technology in 2008. In 2011, he became a staff scientist and a group leader at the Institute for Integrative Nanoscience at the Leibniz Institute in Dresden. In 2013, the IFW-Dresden awarded Dr Chenglin Yan the IIN Research Prize 2013 for his group’s research work. He received the Thousand Young Talents Award from the Chinese Thousand Talents Program in 2014.

Reference

Jie Liu, Tao Qian, Mengfan Wang, Xuejun Liu, Na Xu, Yizhou You, and Chenglin Yan. Molecularly Imprinted Polymer Enables High-Efficiency Recognition and Trapping Lithium Polysulfides for Stable Lithium Sulfur Battery. Nano letters 2017, volume 17, pages 5064−5070.

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Renewable Energy Global Innovations features: Cloud Energy Storage for Residential and Small Commercial Consumers: A Business Case Study

Significance Statement

Both industry and academia have with time come to recognize the significance and potential of energy storage as a prospective resource that can help create a balance between generation and load in power systems. Presently, the world is migrating towards renewable resources with variable renewable energy sources such as wind and photovoltaics. Maintaining the stability of a power system requires real-time balancing of the energy that is consumed and produced. Recent trends are focusing on utilizing distributed energy storage systems by both small residential and commercial users so as to integrate variable renewable energy and reduce electricity bill. Cost, policy, and control efficiency limit the profitability of distributed energy systems and hinders the incentive of both small residential and commercial consumers to purchase the distributed energy storage systems. Among recent power grid and internet technological advances, resource sharing make possible a better utilization of distributed energy systems resources.

Tsinghua University and University of Washington researchers developed a novel way of using energy storage – cloud energy storage – a grid-based storage service that enables ubiquitous and on-demand access to a shared pool of grid-scale energy storage resources. The team aimed at describing how this state of the art technology would be realized and how it is capable of providing energy storage services at substantially lower cost. They also described the cloud energy storage enabling technique that supports both the needs of residential distributed energy systems and the optimal operation of storage resources. Their research work is now published in Applied Energy.

Chongqing Kang and colleagues commenced by conducting empirical works where by, firstly, they proposed the concept of cloud energy storage which utilized central energy storage facilities to provide distributed storage services to residential and small commercial users. They then developed and described the architecture, enabling technologies and operation mechanisms that would facilitate the cloud energy storage. The team then designed the business model of cloud energy storage and demonstrated its profitability using real life residential load and electricity data.

The authors observed that cloud energy storage users can use their cloud batteries just like real energy storage devices. Based on the case study on actual residence load data and electricity price, the team noted that social benefits including, the minimal influence on the percentages of social welfare improved by cloud energy storage due to lower unit price as a result of energy storage. In totality, it was seen that cloud energy storage was more economical than distributed energy systems since the economies of scale has a significant influence on the economy of cloud energy storage.

Chongqing Kang and colleagues successfully described novel concept-cloud energy storage. This new service has the potential to provide the same services as the presently used distributed energy system does, but now at a lower social cost. Its future is so great in that it has the potential to, one day, gather fragments of energy storage resources such as electric vehicles, uninterrupted power supplies and residential distributed batteries. More so, the cloud energy storage business model can presently be merged into some current business models as value-added services.

About The Author

Jingkun Liu is currently a public official in the government of Shuyang Town, Xianghe County, Hebei Province, China. He received his Bachelor’s degrees of Electrical Engineering and Economics from Tsinghua University in 2012 and Peking University in 2013, respectively. He received his Ph.D of Electrical Engineering from Tsinghua University in 2017. He was a visiting student in the University of Washington, Seattle from Sep. 2015 to Sep. 2016.

 His research interests focus on energy storage in power system and power system reliability.

About The Author

Ning Zhang is an associate professor in the Department of Electrical Engineering, Tsinghua University. He got his B.Sc. degree from Tsinghua University, Beijing, China in 2007. He got his Ph.D in electrical engineering with Excellent Doctoral Thesis Award and Excellent Graduate Student Award from Tsinghua University in 2012. After he completed two-year research as a post doctor, he started working in Tsinghua University as a Lecturer in 2014. He was a research associate in The University of Manchester from Oct. 2010 to Jul. 2011 and a research assistant in Harvard University from Dec. 2013 to Mar 2014. He was awarded Yong Elite Scientists Sponsorship Program by Chinese Association of Science and Technology in 2016. His paper is awarded one hundred most influential papers and top articles in outstanding S&T journal of China.

 His research interests include multiple energy system, power system planning and operation with renewable energy (wind power photovoltaic, concentrated solar power).

About The Author

Chongqing Kang is a full professor and the Chairman of Executive Committee of Department of Electrical Engineering. He holds Bachelor’s degrees of both Electrical Power Engineering and Environmental Engineering in 1993, and a Ph.D in Electrical Power Engineering from Tsinghua University in 1997. He has been appointed Professor of Electrical Engineering Department of Tsinghua University since 2005. From 2011 to 2014 he was the Director of Centre for Teaching Excellence, Tsinghua Univ.

He is the recipient of the National Science Fund for Distinguished Young Scholars. He is Fellow of IEEE and IET. He is the senior member of CSEE. He has been on the editorial board of 5 international journals including IEEE Transactions on Power Systems and Electric Power Systems Research and 6 Chinese journals indexed by EI. He won the second prize of National Teaching Achievement Award in 2014. He and his team was granted the Institute Prize in Global Energy Forecasting Competition in 2014. He was granted one gold award and one silver award in the 44th International Exhibition of Inventions in Geneva in 2016.

 His research interests include power system planning, power system operation, renewable energy, low carbon electricity technology, load forecasting and electric market.

About The Author

Daniel S. Kirschen was appointed Close Professor of Electrical Engineering in 2011. From 1994 to 2010, he was Professor of Electrical Energy Systems and Head of the Electrical Energy and Power Systems research group at the University of Manchester in the UK. Prior to joining the academic world, he worked for Control Data Corporation and Siemens-Empros on the development of advanced application software for electric utilities.

His research interests include Integration of renewable energy sources in the grid, power system operation, power system economics, and resilience of the grid to natural disasters.

About The Author

Qing Xia is now a professor at Tsinghua University, Beijing, China. He received his Ph.D. degree from the Department of Electrical Engineering at Tsinghua University in 1989.

 His research interests are mainly power economics, power markets, power system expansion planning, power system reliability, power system load forecasting, and smart grids.

Reference

Jingkun Liu, Ning Zhang, Chongqing Kang, Daniel Kirschen, Qing Xia. Cloud energy storage for residential and small commercial consumers: A business case study. Applied Energy volume 188 (2017) pages 226–236

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Renewable Energy Global Innovations features: Copper nanowire/multi-walled carbon nanotube composites as all-nanowire flexible electrode for fast-charging/discharging lithium-ion battery

Significance Statement

With the rapid evolution of autonomous vehicles, electric vehicles are anticipated to continue to grow rapidly. The electric vehicles offer many benefits such as zero emissions, less noise and vibrations, and are operated by simple electric motors with energy conversion in the range of 80-90%. Electric vehicles also have superior energy resilience since they can be charged using a number of energy sources such as renewable energy, conventional power-plant energy, and regenerative braking energy.

Unfortunately, the electric vehicles suffer some limitations such as cost, safety, mileage, limited lifespan, long charging time, and lack of grid for charging. These problems have led to the development of power systems with Lithium-ion batteries. In a bid to fix cost and mileage issues, the energy density of lithium-ion batteries must be increased, and the only way to improve the energy density would be to come up with new active materials with high theoretical capacity for anodes and cathodes.

Although high capacity materials can be applied to the Li-ion batteries, Li-ion batteries would still take long time to charge owing to their low power densities. Unfortunately, even the recently developed fast chargers with pulse power cannot overcome energy-density fading in the course of high-current charge/discharge reference to the limitation in the energy-conversion reaction of Li-ion batteries.

Researchers led by Professor Youn Sang Kim at Seoul National University, Republic of Korea, proposed a novel all-nanowire electrode structure for fast-charging-discharging Li-ion batteries implementing copper nanowires and multi-walled carbon nanotubes without binders or even conductive agents. Theoretically, the multi-walled carbon nanotubes as the representative one-dimensional carbon-based nanostructure provided fast channels for the effective transport of both electrons as well as ions for Li-ion batteries owing to their unique features that had high aspect ratio as well as large surface area. However, the large voltage range between charging and discharging is normally limited the multi-walled carbon nanotubes to be used for active materials in full cells, due to their morphology and resistivity. The authors firstly overcame this limitation of multi-walled carbon nanotubes, and their work is published in peer-reviewed journal, Nano Research.

The authors fabricated a lightweight 3-dimensional composite anode for a fast charging-discharging Li-ion battery implementing two of 1-dimensional nanomaterials, which were copper nanowires and multi-walled carbon nanotubes. Reference to superior electrical conductivity, large surface areas, and high aspect ratio of these materials, the copper nanowire-multi walled carbon nanotubes composite with 3-dimensional structure provided several advantages concerning transport channels of ions and electrons.

The copper nanowires applied as the current collector and multi-walled carbon nanotubes applied as the active materials provided a number of benefits for enhancing the Li-ion battery performances. These included efficient ion diffusion, thick electrode formation, fast electron transport, and flexible cell design. As an advanced binder-free anode, the proposed composite film with tunable thickness indicated a significant low sheet resistance and internal cell resistance. The copper nanowires network with 3-dimensional structure functioned as a rigid framework connected to the multi-walled carbon nanotubes. They prevented the shrinkage and expansion of the multi-walled carbon nanotubes owing to swelling and aggregation, and minimized the effects of volume change of the carbon nanotubes during the charging-discharging process.

Both the full and half-cells of the Li-ion batteries with 3D-composite film anode indicated high specific capacities and Coulombic efficiencies even at high currents. The authors were able to overcome, for the first time, the limitations of carbon nanotubes as anode materials for fast charging and discharging Li-ion batteries by implementing copper nanowires, and the proposed anode can be used in flexible Li-ion batteries. This new development could result in the development of ultrafast chargeable Li-ion batteries for electric vehicles.

About The Author

Zhenxing Yin completed his Bachelor’s studies at Changchun University of Technologies (China) in 2012. Then, he received his Master’s degree at Seoul National University (Republic of Korea) in 2014, and is currently a Ph.D. candidate at Graduate School of Convergence Science and Technology, Seoul National University. His research interests mainly focus on copper nanowire synthesis and applications.

About The Author

Prof. Jeeyoung Yoo is the research professor in Graduate School of Convergence Science and Technology, Seoul National University at Seoul, Korea. A graduate of Chung-Ang University, she holds a Bachelor of Chemical Engineering, Master of Chemical Engineering, and PhD in Chemical Engineering, specializing in electrochemical engineering. And she is an expert in energy storage materials and device-related research and development.

About The Author

Prof. Youn Sang Kim is the Professor in Graduate School of Convergence Science and Technology, Seoul National University at Seoul, Korea. He received Ph.D. in the Department of Chemical Engineering from Seoul National University at Seoul, Korea in 2002 and then worked for two years as a postdoctoral fellow in Massachusetts Institute of Technology, USA. His current research interests are concentrated on interface engineering for novel devices such as energy harvesting devices, oxide or hybrid TFTs, oxide diodes and printing electronics.

Reference

Zhenxing Yin, Sanghun Cho, Duck-Jae You, Yong-keon Ahn, Jeeyoung Yoo, and Youn Sang Kim. Copper nanowire/multi-walled carbon nanotube composites as all-nanowire flexible electrode for fast-charging/discharging lithium-ion battery. Nano Res. 2017, DOI: 10.1007/s12274-017-1686-0.

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Renewable Energy Global Innovations features: CH3NH3PbI3 Converted from Reactive Magnetron Sputtered PbO for Large Area Perovskite Solar Cells

Significance Statement

Exponential growth in both interest and attention paid to the organic-inorganic metal halide perovskites materials have spiked undeniable concern of late. The outstanding properties possessed by these materials carry all the credit. These properties, including: long exciton diffusion length, strong absorption coefficients, low cost, ease of Synthesis and environmental-friendliness have led to great advancement in perovskite solar cells such as improving the power conversion efficiency from around ten percent in the early years of this decade to about twenty percent at present. Recent studies have shown that the quality and morphology of the perovskite films are crucial to its photoelectric properties and that they directly influence the performance of the resultant perovskite solar cells. Even though several deposition techniques have been proposed for synthesis of the perovskite light-absorption layers, great difficulties are still being encountered in the bid to fabricate perovskite films with both satisfactory coverage and uniformity over a large area.

Researchers led by Professor Meicheng Li at the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources in North China Electric Power University developed a novel process route based on direct current reactive magnetron sputtering in the preparation of the CH₃NH₃PbI₃ film. They aimed at presenting a complete approach for the fabrication of large area perovskites solar cells with the advantages of easy control, economical and requiring less use of toxic reagents but with diverse potential applications. Their research work is now published in Solar Energy Materials & Solar Cells.

The research team began by fabricating the lead oxide film on an FTO-glass substrate coated with a nanocrystalline rutile titania by using a pure metallic lead target in an argon-oxygen mixture. They then converted the prepared lead oxide film to CH₃NH₃PbI₃ through the sequential reactions setup in isopropanol solution of CH₃NH₃I. Eventually, the research team fabricated solar cells of a complex structure that employed nanocrystalline rutile titania as the contact layer of the photovoltaic devices.

The authors were able to observe that the as-prepared perovskite film exhibited a surface morphology of high uniformity and excellent coverage over a large scale. Also the crystal grains were seen to reach the size of up to 600 nm, which is beneficial to extract photo-generated electrons more effectively and prepare the perovskites solar cells at low temperature.

The new approach employed in their study is technically spin-coating-free for the formation of large area CH₃NH₃PbI₃ film and exhibits advantages ranging from easy process control, economical all the way to less use of toxic reagents. Of crucial importance, it is expected that this novel technique will be applied for the synthesis of perovskites solar cells or other thin-film devices and thus entails potential applications and practical significance.

The schematic illustration of CH3NH3PbI3 formation (on NRT-coated FTO glass substrate) through the sputtered PbO.

The top-view SEM of CH3NH3PbI3 converted from the sputtered PbO, where the insertions are the corresponding one with high magnification.

About The Author

Zhirong Zhang is a Ph.D candidate, who studied at the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources in North China Electric Power University, under the supervision of Prof. Meicheng Li. He received his B.S. degree majored in Radio Physics, from Lanzhou University, in 2008. His research interests include development of thin film solar cells and the design & application of photovoltaic system. He has been working on perovskite solar cells since the year of 2013.

About The Author

Prof. Meicheng Li is the Director of New Energy Materials and PV Technology Center, and the Vice Dean of the School of Renewable Energy, North China Electric Power University. He obtained his PhD at Harbin Institute of Technology in 2001. He worked in University of Cambridge as Research Fellow from 2004 to 2006. He won the Excellent Talents in the New Century by the ministry of education in 2006. His current research topic is the New Energy Materials and Devices, such as perovskite solar cells, lithium ion battery system. Till now, he contributed more than 200 journal articles and performed the review services for about 80 SCI journals. He got almost more than 10 items of awards for the science and technology success. He served more than 20 academic conferences as the chair, track co-chair or session chair. He is an executive fellow of the China Energy Society, fellow of Chinese Society for Optical Engineering.

Website , Research Gate.

Reference

Zhirong Zhang, Meicheng Li, Wenjian Liu, Xiaopeng Yue, Peng Cui, Dong Wei. CH₃NH₃PbI₃ converted from reactive magnetron sputtered lead oxide (PbO) for large area perovskite solar cells. Solar Energy Materials & Solar Cells, volume 163 (2017) pages 250–254.

 

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Renewable Energy Global Innovations features: Titanium Oxide Nanofibers Decorated Nickel-Rich Cathodes as High Performance Electrodes in Lithium Ion Batteries

Significance Statement

Layered cathode active materials partially-substituted cobalt with transition metals and spinel active materials have been received more attention due to their cost effectiveness as compared to lithium cobaltate. Scholars have realized with time that the spinel cathode active materials are safe with limited specific capacities while layered cathode active materials possess high specific capacity with safety issues. Presently, layered cathode active materials are more preferred as cathode materials for lithium ion batteries, where nickel-rich layered cathode active materials are front runners except for safety issues, due to their high capacity. To overcome the safety issue challenge, measures, such as the substitution of the transition metal ions with other metal counter ions and the modification of the surface by means of coating with metal oxides, have been put in place.

Nanoparticle coatings on layered cathode active materials have been known to suppress the thermal reaction between the electrode and electrolyte. It has thus been seen necessary to coat or decorate the surface of the cathode since probable exothermic reaction starts from the cathode surface when the electrolyte is decomposed. Extensive studies have been performed on coating materials that inhibit this reaction but little exists about nanofibers-based metal oxides decorated on lithium nickel cobalt aluminum oxide cathode active materials.

Professor Chang Woo Lee and colleagues from the Department of Chemical Engineering, College of Engineering, Kyung Hee University, Yongin, Gyeonggi, South Korea, proposed a study to modify the surface of lithium nickel cobalt aluminum oxide particles by decorating them with titania nanofibers. They aimed at comparatively studying, with the novel lithium nickel cobalt aluminum oxide, the various quantities of titania nanofibers decorated over lithium nickel cobalt aluminum oxide (LNCA). Their research work is now published in the peer-reviewed journal, Journal of Industrial and Engineering Chemistry.

The researchers commenced their empirical procedure by obtaining titania nanofibers precursor through electrospinning a sol-gel polymeric solution. They then obtained the LNCA precursor. The titania nanofibers precursors were split at 0.5 wt%, 1 wt% and 1.5 wt% before addition of the LNCA precursor powders. The precursor powder mixture was then sintered at 465^oC for three hours and then calcined at 850^oC for five hours in air. The team then conducted an X-ray photoelectron spectroscopic analysis to investigate the chemical composition of the cycled electrode surface. The team eventually obtained cathode samples and used them to conduct differential scanning calorimetry scans.

The authors also observed that the increase of titania nanofibers decoration over 1wt% ratio showed negative effect during the electrochemical process, as observed using electrochemical impedance spectra for the 1.5wt% titania nanofibers-decorated LNCA. Hence usage of titania nanofibers more than 1wt% was excluded from detailed investigation. The surface modification of LNCA electrodes by 1wt% titania nanofibers decoration greatly increased the cycleability, capacity, and thermal stability of lithium ion batteries at room temperature as well as at elevated temperature. Among titania nanofibers decorated LNCAs, the 1wt% titania nanofibers -decorated LNCA cathode had shown better capacity retention of 89.2% and 81.9% at room and elevated temperature, respectively.

The results of their study second the suggestion of the applicability of titania nanofibers as surface modifiers in order to enhance the electrochemical and thermal properties of lithium ion batteries. Moreover, it has been seen that the capability of the titania nanofibers-decorated LNCA was enhanced compared to that of the pristine LNCA. The onset temperature of thermal decomposition is also shifted towards higher temperature for titania nanofibers-decorated LNCA electrodes than pristine LNCA electrodes.

About The Author

Professor Chang Woo Lee is currently serving in the Department of Chemical Engineering and also Director of Center for the SMART Energy Platform at Kyung Hee University, S. Korea. He joined Kyung Hee University in 2006, having received B.S. and M.S. degrees in 1994 and 1996, respectively, at Kyung Hee University, S. Korea and a Ph.D. at the Illinois Institute of Technology, USA in 2003, both in the field of Chemical Engineering. Prof. Lee has also worked as a Senior Researcher at Korea Electrotechnology Research Institute (KERI) since he obtained Ph.D. degree. He was appointed as a Visiting Scholar in the Materials Department, College of Engineering and Applied Science, at the University of Wisconsin-Milwaukee, for the 2012-2015 academic year.

Prof. Lee’s research is focused on electrochemical energy storage & conversion and seek to synthesize energy materials in metallic micro- and/or nanostructures for the purpose of improving electrochemical properties in the area of batteries, supercapacitors, and fuel cells.

About The Author

Mr. Kijae Kim is currently a Ph.D. candidate at the Department of Chemical System Engineering in The University of Tokyo, Japan. He received his B.S. and M.S. degrees in the Department of Chemical Engineering at Kyung Hee University, S. Korea. He has studied synthesis and analysis of electrode materials for energy storage devices for the M.S. under the supervision of Prof. Chang Woo Lee. He has published several scientific papers and received the Best Poster Award from Korean Battery Society and bachelor graduation with honors.

About The Author

Dr. K. Prasanna obtained his B.S. and M.S. degrees from Bharathidasan University and Anna University in India, respectively. He then joined as assistant professor in the Department of Biotechnology at Vinayaka Missions University, Salem. He joined as a Ph.D. student under Professor Chang Woo Lee in the Department of Chemical Engineering at Kyung Hee University, S. Korea in September, 2011 and received his Ph.D. degree in Aug, 2015. He then continued his career as a postdoctoral fellow at Electrochemical Energy Storage and Conversion Laboratory, Kyung Hee University for two years. Currently he is working as a postdoctoral fellow in Technical University of Denmark, under the H.C. Ørsted Postdoc programme, co-funded by Marie Skłodowska-Curie Actions. His recent research interests include supercapacitors, Li-ion batteries, Mg-ion batteries, and Metal-air batteries.

About The Author

Dr. T. Subburaj received his Ph.D. at Kyung Hee University, South Korea in 2015 under the supervision of Prof. Chang Woo Lee in the Department of Chemical Engineering and he received his M.S. degree from the Department of Chemical Engineering, Anna University, Chennai, India in 2010. Currently, he works with Prof. Chung-Hsin Lu as a MoST Postdoctoral Scholar at National Taiwan University, Taiwan. His research interests focus on synthesis and applications of nanostructured and hybrid materials for electrochemical energy storage and conversion, including rechargeable batteries, electrochemical capacitors, and solar cells.

About The Author

Dr. Yong Nam Jo received his M.S. and Ph.D. degrees in Department of Chemical Engineering from Kyung Hee University, S. Korea in 2013 and 2017, respectively, under the supervision of Prof. Chang Woo Lee. He received Best Thesis Award for the Ph.D. from the President of Kyung Hee University and also several Best Poster and Outstanding Paper Awards from domestic and international conferences. He is currently working as a postdoctoral fellow at the Center for SMART Energy Platform at Kyung Hee University. His current research is focused on enhancement of materials for energy storage and conversion with Li-ion batteries and metal-air batteries.

Reference

Subburaj, Yong Nam Jo, K. Prasanna, Ki Jae Kim, Chang Woo Lee. Titanium oxide nanofibers decorated nickel-rich cathodes as high performance electrodes in lithium ion batteries. Journal of Industrial and Engineering Chemistry, volume 51 (2017) pages 223–228.

 

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Renewable Energy Global Innovations features: Future European biogas: Animal manure, straw and grass potentials for a sustainable European biogas production

Significance Statement

In a bid to meet the European Union political target for energy and climate, biogas production will play a critical role owing to its flexibility and storability as an energy carrier, a wide range of biological sources that can be implemented for its synthesis, and its established implementation in an array of applications. The implementation of anaerobic digestion for biogas production is still widespread as a critical bioenergy production path reference to its robustness in design arrangements.

Anaerobic digestion serves several applications. It offers a treatment pathway for minimizing huge amounts of complex organic matter, converting a good number of these molecules into monomers, for example, carbon dioxide and methane, which can be used in the energy sector. Above all, the nutrient-rich digestate produced from the anaerobic processes can be recycled on farmlands as organic fertilizers as alternatives to chemical fertilizers that cause eutrophication of fresh water bodies.

The choice of substrates used in the production of biogas has been discussed extensively, particularly, in relation to the use of energy crops. Negative economic and environmental issues related to the use of cultivated energy crops for bioenergy production has been reported in literature. Therefore, these substrates will definitely fall out favor as primary feedstock considered for biogas anaerobic digestion process, and thus alternative sources are required.

Agricultural production residues can be incorporated with the EU directive on the use of energy from renewable sources sustainability criteria. In contrast to the existing literature on the topic, researchers led by Professor Jens Bo Holm-Nielsen at Aalborg University in Denmark focused on the biomass and biogas energy potential from a collection of particular agricultural residues that have been documented to enhance in biogas yield when co-digested in biogas production. Their research work is published in Biomass and Bioenergy.

The main aim of their study was to forecast and map the biogas and biomass energy potential from particular potentially sustainable agricultural residues that have been documented to enhance in biogas yields when co-digested in the production of biogas for the EU28 in the year 2030. The authors considered residual types including, animal manure, excess grass from permanent and rotational meadows and grasslands, and straw byproducts from cereal production.

The research team projected energy potential from grass, manure and straw to be in the range of 1.2×10³-2.3×10³PJ/y for the European Union in 2030. The United Kingdom and Germany were identified to have the highest energy potential. The outcomes of the study indicate that there is a huge base for agricultural residues well suited for co-digestion all over Europe that are perfect substitutes to energy crops.

The study found that co-digestion of animal manure incorporating straw and grass is a potential that will enhance the efficiency and economic feasibility of the European Union biogas production in 2030. More technological development and implementation may be necessary if the biomass resources are to be used efficiently. Acquisition and processing of the selected biomasses are challenges that must be addressed before realizing a full potential. However, production of energy based on these residues is a more sustainable and economically viable method for developing the EU biogas industry keeping in mind the potential issues in relation to sustainability.

About The Author

Name: Jens Bo Holm-Nielsen

Date and place of birth: 31th of March, 1954, Fanoe Island, Denmark Nationality: Danish
Civil Status: Married – Lis Ingemann & 3 Children; Sara, Thomas and Anne
Contact details: e-mail: jhn@et.aau.dk; cell: +45 2166 2511.

1st University Degree 1980. M.Sc.: Agricultural Systems, Crops & Soil Science, from KVL, Royal Veterinary & Agricultural University, Copenhagen, Denmark.

2nd University Degree 2008. Ph.D. degree from Aalborg University – Esbjerg Institute of Technology. Process Analytical Technologies for Biogas Systems. Esbjerg, Denmark.

Languages: Danish and Scandinavian languages, English, (German, French – partial proficiency)

Professional career:

1980-85: Riber Kjærgaard Agricultural College, Lecturer

1985-93: Ribe, Bramming, Esbjerg Farmers Organisation, Farming Advisor

1993-95: University Center South Jutland, Esbjerg; Senior Project Manager

1995-00: University Center South Jutland, Esbj.; Head of Bioenergy Section

2000-08: University of Southern Denmark, Esbj. Head of Bioenergy Depart.

2002-08: University of Aalborg, Esbjerg: Senior lecturer & Ph.D. researcher

2008-2010: University of Aalborg, Esbjerg: Assistent Professor & Head of Center for Bioenergy and Green Engineering.

2010 – …..: Aalborg University – Esbjerg Campus: Associate Professor & Head of Energy Section – Department of energy technology & & Head of Center for Bioenergy and Green Engineering.

Years of experience in the field of Biorefinery concepts and Biogas production – Anaerobic Digestion. Implementation projects of Bioenergy Systems. Experience of a variety of EU and UN projects. Organiser of international conferences, workshops and training programmes in Europe, Central Asia and China.

Awards, honors

2000: Honorary Bioenergy Center, SDU, Denmark and partners – Best National Renewable Energy Partnership. Awarded by DG TREN – EU Commission

2010: D.L. Massart Award in Chemometrics. Awarded by the Belgian Chemometrics Society for the best world-wide Ph.D. thesis in the research field during the period of 2008-2010.

Field of research, teaching & supervising:

Research: Managing research, development and demonstration programmes in integrated agriculture, environment and energy systems solutions.

Fulfilled biomass and bioenergy R & D projects. Main focus in biofuels, biogas and biomass resources. New focus since 2008 – Biomass pre-treatment platforms for 2. and 3. generation biorefinery production

Lecturing and graduate supervision: Courses and project supervising in fermentation processes, anaerobic digestion processes and systems. Biogas purification, Nutrient management and balances and upgrading technologies. Agricultural and environmental projects. Biomass resource studies. Optimal utilization of biomass resources and conversion technologies. Bioenergy and Renewable energy system integration.

Training programmes: International courses, training programmes and supervision for academic staff, governmental bodies and experts in bioenergy systems and integrated solutions. Core competences in bioenergy technologies and biomass ressourse conversion to biogas or biofuels.

www.energy.aau.dk; www.vbn.dk; (Search JBHN)

Center for Bioenergy and Green Engineering, AAUE

Established at SUC 1995, transferred to SDU 2000, and as a joint group at SDU/AAUE from 2002-2008. Centre for Bioenergy and Green Engineering established at AAUE 2009. Biomass resource studies. Specific research on anaerobic digestion systems. Biomass and organic waste system analysis and optimisation. Ongoing several Liquid Biofuels projects and Biorefienery studies.

Selected Publications:

1. Holm-Nielsen et al.; Joint biogas plant – agricultural advantages, circulation of N, P and K. Report made for the Danish Energy Agency, Ministry of Energy, 1.th.Edition 1993, 2.nd. Edition 1997. Downloads from www.sdu.dk/bio;
2. Holm-Nielsen; participated in UN-China conference with the lecture; Rapid Commercialisation of Renewable Energy Systems. Danish and European experience of Biogas Systems. Workshop and strategy planning for biogas technology in China. UNDP/GEF Project, Beijing, China 2-7.04.2000
3. Holm-Nielsen J.B., al Seadi T.: Manure-based biogas systems – Danish Experience. Chapt. 17; p 377-394 in Resource Recovery and Reuse in Organic Solid Waste Management. IWA Publishing, 2004. ISBN 1 84339 054 X
4. Holm-Nielsen J.B., Dahl C.K., Esbensen K.H.: Representative sampling for process analytical characterisation of heterogeneous bioslurry systems – a reference study of sampling issues in PAT. Chemometrics and intelligent laboratory systems vol. 83, 114 – 126 (2006) ScienceDirect, Elsevier. DOI: 10.1016/j.chemolab.2006.02.002
5. Holm-Nielsen J.B., Andree H., Lindorfer H., Esbensen K.H.: Transflexive embedded near infrared monitoring for key process intermediates in anaerobic digestion/biogas production. Journal of Near Infrared Spectroscopy vol. 15, 123-135 (2007) ISSN 0967-0335. DOI: 10.1255/jnirs.719
6. Holm-Nielsen J.B., Lomborg C.J., Oleskowicz-Popiel P., Esbensen K.H.: On-line Near Infrared monitoring of glycerol-boosted anaerobic digestion processes – evaluation of Process Analytical Technologies. Biotechnology and Bioengeneering, Vol. 99, No.2, 302 – 313, (2008), Wiley Periodicals inc. – InterScience. DOI: 10.1002/bit21571
7. Holm-Nielsen J.B., Madsen M., Oleskowicz-Popiel P.: Predicted Energy Crop Potentials for Bioenergy Worldwide and for EU-25. Proceedings World Bioenergy 2006, Conference on Biomass for Energy, Jönköping, Sweden, 30. May – 1.June 2006.
8. Holm-Nielsen J.B., Oleskowicz-Popiel P., al Seadi T.: Energy Crop Potentials for Bioenergy in EU-27. Proceedings 15.th European Biomass conference, Berlin, Germany 7-11 May 2007. ISBN 3-936338-21-3.
9. Holm-Nielsen J.B. and Oleskowicz-Popiel P. 2007: The Future of Biogas in Europe: Visions and targets until 2020; Proceedings: European Biogas Workshop – Intelligent Energy Europe, 14- 16 June 2007, Esbjerg, Denmark.
10. Holm-Nielsen J.B.: Process Analytical Technologies for Anaerobic Digestion Systems. – Robust Biomass Characterisation, Process Analytical Chemometrics, and Process Optimisation. Ph.D. Thesis. ACABS-Research Group, Esbjerg Institute of Technology, Aalborg University, August 2008, ISBN 978-87-7606-030-5
11. Holm-Nielsen et al.: Biogas technologies and further treatments steps of co-digestion of animal manure. International Workshop – OECD & USDA; Livestock Waste Treatment Systems of The Future: A challenge to environmental quality, food safety, and sustainability. April 2008, USA, Bioresource Technology 100 (2009) 5478 – 5484. Doi: 10.1016/j.biotech.2008.12.046
12. Holm-Nielsen: Key Note Speaker. Renewable Energy and Climate Change Policies in Denmark and Europe. Bioenergy and Biogas as case examples. Conference: Growing the Margins – Green Energy and Economy, March 10-11, 2010, London, Ontario, Canada.

Full Bibliography and publication list since 2004 can be found at:

www.vbn.dk; – search; Jens Bo Holm-Nielsen.

Earlier bibliography and publication list can be achieved by mailing to: jhn@et.aau.dk;

Contact details:

Jens Bo Holm-Nielsen, M.Sc., Ph.D.

Head of Esbjerg Energy Section
Department of Energy Technology,

Head of Center for Bioenergy and Green Engineering

Aalborg University – Esbjerg Campus
Niels Bohrsvej 8, DK-6700 Esbjerg, Denmark. www.et.aau.dk
Phone: +45 21 66 25 11,  e-mail:  jhn@et.aau.dk

About The Author

A.Katharina P. Meyer, PhD, M.Sc.
paarupmeyer@gmail.com
Education
2012-2015: PhD. Sustainable Biomasses. Department of Energy Technology, AAU Esbjerg.
2009-2011: M.Sc. in Environmental and Resource Management, AAU & SDU Esbjerg
2006-2009: B.Sc. in Environmental and Resource Management, AAU & SDU Esbjerg
Employment:
2017 – now: Danish Energy Agency, EUDP
2015-2017: Postdoc, Department of Energy Technology, AAU Esbjerg.
2012-2015: PhD student, Department of Energy Technology, AAU Esbjerg.
2011-2012: Esbjerg Kommune. Department of Climate and Sustainability.
Research​ ​projects​ ​and​ ​key​ ​tasks
2016-2017: Large Scale Bioenergy Lab. EU funded Interreg5A Project.
Project coordination and management.
2015-2016: Demonstration af AD Booster systemet for øget biogasproduktion (AD Booster).
EUDP project.
Representative sampling of liquid and solid manure samples on biogas plant.
Characterization of manure samples in lab
Analysis of mass flow and efficiency for screw press
BMP tests of samples
2012-2015: Large Scale Bioenergy Lab. EU funded Interreg4A Project
Screening of sustainable resources for biogas in the regions.
Spatial analyses of availability and growth yields of biomass resources
Analysis of energy balances when utilising new biomass substrates for biogas in the project
region
Research​ ​competences
Biomethane potential tests (BMP), Spatial analyses, Data management and visiualisation
Characterization of biomasses, Representative sampling (TOS), Multivariate dataanalysis
Energy balances (Net Energy Gains and Energy Returns on Invested Energy)
Publications
– Future European biogas : Animal manure, straw and grass potentials for a sustainable
European biogas production. / Meyer, A. K.P.; Ehimen, E. A.; Holm-Nielsen, J. B. In: Biomass
and Bioenergy, 06.2017. Journal article
– The potential of surplus grass production as co-substrate for anaerobic digestion : A case study
in the Region of Southern Denmark. T/ Meyer, A. K. P.; Schleier, C.; Piorr, H. P.; Holm-Nielsen,
J. B. In: Renewable Agriculture and Food Systems (Print), Vol. 31, No. 4, 08.2016, p. 330-349.
Journal article
– The energy balance of utilising meadow grass in Danish biogas production. / Meyer, A. K. P.;
Raju, C. Sangaraju; Kucheryavskiy, S. V.; Holm-Nielsen, J. B.. In: Resources, Conservation and
Recycling, Vol. 104, No. Part A, 11.2015, p. 265–275. Journal article
– Bioenergy production from roadside grass : A case study of the feasibility of using roadside
grass for biogas production in Denmark. / Meyer, A. K. P.; Ehimen, E. A.; Holm-Nielsen, J. B.
In: Resources, Conservation and Recycling, Vol. 93, 2014, p. 124-133. Journal article
– Sustainable Biomass Resources for Biogas Production : Mapping and Analysis of the Potential
for Sustainable Biomass Utilization in Denmark and Europe. / Meyer, A. K. P. Department of
Energy Technology, Aalborg University, 2015. 89 p. Ph.D. thesis.

Reference

A.K.P. Meyer, E.A. Ehimen b, J.B. Holm-Nielsen. Future European biogas: Animal manure, straw and grass potentials for a sustainable European biogas production. Biomass and Bioenergy, Available online 1 June 2017.

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