ICAC 2018: The First International Conference Focused on NCM

Oct 10, 2018 - their high energy densities and long cycle lives. As market growth ... in EVs are, however, still inadequate, failing to meet the drivi...
0 downloads 0 Views 7MB Size
Download PDF
http://pubs.acs.org/journal/aelccp

ICAC 2018: The First International Conference Focused on NCM & NCA Cathode Materials for Lithium Ion Batteries Downloaded via 91.243.93.126 on October 20, 2018 at 10:11:49 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

A

mong the various types of secondary batteries, lithiumion batteries (LIBs) are considered the most promising power sources for electric vehicles (EVs) because of their high energy densities and long cycle lives. As market growth and customer demand for EVs increase, so do the demands on battery performance.1,2 Current state-of-the-art LIBs employed in EVs are, however, still inadequate, failing to meet the driving range requirement of 300 miles per charge, which is recognized as the threshold for public acceptance of future EVs.3,4 Because the energy density of a LIB is severely limited by the specific capacity of the cathodes, attempts to increase the drive range and lifetime of EV batteries have mostly focused on identifying and developing cathode materials with high energy densities and stabilities. Although myriad LIB cathode materials have been proposed, layer-structured nickel cobalt aluminum (NCA) and nickel cobalt manganese (NCM) cathodes5−8 are the most successful cathode materials that have been employed in recent EVs. However, reaching the threshold discharge capacity using these two materials has been challenging because, although the discharge capacity is increased by Ni-enrichment in the cathode material, rapid capacity fading occurs during cycling.9−11 Therefore, the development of excellent Ni-rich cathode material with high capacity and outstanding safety that would enable EVs to drive more than 300 miles is an attractive theme not only in academia but also in industry. Following this trend, the International Conference for Advanced Cathodes in Lithium-Ion Batteries (ICAC) was held in the HIT building, Hanyang University, Seoul, Korea (September 10−12, 2018). The conference gathered more than 250 researchers and students from companies and academia from all around the world and is the first conference focusing on NCM and NCA cathode materials. (Figure 1) NCM and NCA are not only fundamental materials for LIBs but also core technologies in the energy industry, for example, in EVs and energy storage systems (ESSs). To share research about cathode materials, Prof. Yang-Kook Sun, organizer of ICAC 2018 and senior editor of ACS Energy Letters, who has researched cathode materials for decades,12−17 invited renowned researchers and companies to ICAC. The objective of the conference was to review current research progress and discuss the challenges facing NCM and NCA cathode materials for LIBs. Even though it was the first conference focusing on this narrow research topic (NCM and NCA), 32 world leaders from research and industry were invited to ICAC. In addition, delegates of the Pacific Northwest National Laboratory (PNNL) and the Department of Energy (DOE), which lead the “Battery500 Consortium,” attended ICAC 2018 (Figure 2). We were delighted to have the internationally renowned scientists listed in Table 1 present their work about state-of the-art advances in the electrochemical systems related to NCM and NCA cathodes. © XXXX American Chemical Society

Figure 1. Conference venue for ICAC 2018.

Figure 2. Opening ceremony by Prof. Yang-Kook Sun, organizer of ICAC 2018 (top), and invited talk by Prof. Juergen Garche (Ulm University) on “Safety Behavior of Li-Ion Battery Cathode Materials” (bottom) in the conference hall.

Received: October 9, 2018 Accepted: October 10, 2018

2757

DOI: 10.1021/acsenergylett.8b01926 ACS Energy Lett. 2018, 3, 2757−2760

Energy Focus

Cite This: ACS Energy Lett. 2018, 3, 2757−2760

Energy Focus

ACS Energy Letters Table 1. Invited Talks for ICAC 2018a presenter

title

ref

Yang-Kook Sun (Hanyang University)

Progress in High-Capacity Concentration Gradient Cathodes for Next-Generation Lithium Batteries

Claude Delmas (Université de Bordeaux) Kiyoshi Kanamura (Tokyo Metropolitan University) Sung-Jin Kim (BMW) Lianqi Zhang (Tianjin University of Technology)

The NMC Positive Electrode Materials from the Solid State Chemistry: Point of View Degradation of NCA (LiNi1−x−yCoxAlyO2) in 18650 Cell

Seung-Taek Myung (Sejong University) Sang-Young Lee (UNIST) Yoon-Seok Jung (Hanyang University) Wang Mo Jung (LG Chem) Jason Zhang (PNNL) Won-Sub Yoon (Sungkyunkwan University) Tien Q. Duong (U.S. Department of Energy) Jung Hoon Song (RIST) Chongmin Wang (PNNL) Dong Joon Ihm (Umicore) Honghe Zheng (Soochow University) Feng Lin (Virginia Tech) Byung Chan Han (Yonsei University) Y. Shirley Meng (University of California San Diego) Songhun Yoon (Chung-Ang University) Dongjoon Ahn (LG Chem) Juergen Garche (Ulm University) Ji-Yong Shin (BASF) Jun Liu (PNNL) Kyung Yoon Chung (KIST) Shinichi Komaba (Tokyo University of Science) Moon Ho Choi (Ecopro BM) Chong Seung Yoon (Hanyang University) Guanglei Cui (Qingdao Institute of Bioenergy and Bioprocess Technology) Hyungsub Kim (KAERI) Fabio Masiello (Malvern PANalytical) Nam-Soon Choi (UNIST)

Potential and Limitation of Ni-Rich Cathode Materials in Batteries for Automotive Applications Designing and Synthesis of Core−Shell Structured NCM or NCA Cathode Materials for Liquid and Solid Li-ion Batteries An Effective Method to Reduce Residual Lithium Compounds on Ni-Rich Cathode Materials One-Dimensional Building Block Strategy for Advanced Lithium-Ion Battery Electrodes Interfacial Engineering for Layered Oxide Cathode Materials for All-Solid-State Lithium-Ion Batteries High Ni Cathode Material for High Energy Density Lithium-Ion Batteries High Voltage Operation of Ni-Rich NMC Cathodes Enabled by Stable Electrode/Electrolyte Interphases Identifying Key Factors of Ni-Rich Cathode Performance: Structural Aspects Overview of the Advanced Battery Materials Research (BMR) Program and the Battery500 Consortium High-Speed Coprecipitation Process for NCM Cathode Precursor Using a Taylor−Couette Reactor Microscopy and Spectroscopy Diagnosis Guided Optimization of Layer Structured Cathode for LithiumIon Batteries Evolution of NMC Cathode Active Materials for Lithium Ion Batteries In-Situ Development of Elastic Solid Electrolyte Interphase via Nano-Regulation and Self-Polymerization of Unsaturated Organic Compounds on Graphite Surface Manipulating the Interfacial Chemistry of Layered Cathode Materials by Exploring 3D Heterogeneous Chemical Distribution Unexpectedly High Energy Density of a Li-Ion Battery by Oxygen Redox in LiNiO2 Cathode: First Principles Study Exploring the Ultimate Limits of Intercalation Layered Oxides

12, 14, 16 18,19 20 − 21 22 23 24 − 25, 26 27 28 − 29, 30 − 31 32 33 34

Novel Preparation Method for Advanced Cycling Performance in NiCoAl (NCA) Layered Cathode Materials Structural Enhancement of Bulk and Surface in High Nickel Layered Lithium Transition-Metal Oxide for Li-Ion Batteries Safety Behavior of Li-Ion Battery Cathode Materials High Energy Ni-Rich Cathode Materials for Automotive Applications Development and Optimization of Electrode/Electrolyte Materials for Extended Cycling Life of High Energy Rechargeable Li Metal Batteries Characterization of LiNi0.8Co0.15Al0.05O2/Li1.3Al0.3Ti1.7(PO4)3 Composite Cathode in All-Solid-State Lithium-Ion Batteries Tungstate Solid as Additive into NMC Cathode Advanced Nickel-Rich Cathode Material for High Energy Density Lithium Ion Batteries Characterization of Cathode Materials using Transmission Electron Microscopy Rigid-Flexible Coupling Solid-State Electrolytes for High Energy Density Lithium Batteries

35

39 − 40 41

Neutron Diffraction Researches on Layered Cathode Materials for Lithium Rechargeable Batteries In Situ/Operando Measurements of Lithium-Ion Batteries on a Laboratory X-ray Diffractometer Molecularly Engineered Electrolyte Additives for the Stabilization of Electrolyte−Cathode Interfaces

42 − 43

− 36 − 37 38

a

References for invited talks from company and unpublished studies were excluded.

ICAC at the banquet (Figure 3). The talks were about their past research experiences and gave thanks to all staff and managers, as well as looking forward to other future conferences and the increased participation of female researchers. ICAC 2018 was a magnificent meeting thanks to the participants from all around the world and the staff who worked hard to organize and prepare the conference. Special thanks are owed to the chairs of each conference day: Jason Zhang (PNNL), Kiyoshi Kanamura (Tokyo Metropolitan University), Jun Liu (PNNL), Y. Shirley Meng (University of California, San Diego), Yoon-Seok Jung (Hanyang University), and Chongmin Wang (PNNL). In addition, we appreciate ACS Energy Letters for providing T-shirts for staff and participants (Figure 4). We hope that all participants had fruitful experience and were motivated by the many impressive ideas from ICAC 2018. The second ICAC will be held on November 12−14 next year. On the basis of the

The oral presentations continued from Monday morning until Wednesday afternoon. The coffee breaks were filled with lively discussions about NCM and NCA cathode materials. The invited speakers discussed various aspects related to NCM and NCA materials, including synthesis, structural analysis, electrochemical mechanisms, interfacial chemistry, safety behavior, and their Ni-rich compositions (Table 1). The discussion ranged from active material particle analysis to systematic research into EV and ESS applications. It was a productive meeting for the exchange of novel ideas and provided an excellent forum for developing collaborations between academia and industry. To foster cohesion and collaboration between cathode material specialists, the organizer held a special dinner (Monday) for invited speakers and a banquet (Tuesday) for all researchers and companies. Beginning with thanks to all attendees by the organizer, Claude Delmas, Juergen Garche, Kiyoshi Kanamura, Tien Duong, and Shirley Meng gave speeches in celebration of the 2758

DOI: 10.1021/acsenergylett.8b01926 ACS Energy Lett. 2018, 3, 2757−2760

ACS Energy Letters

Energy Focus

■

ACKNOWLEDGMENTS

■

REFERENCES

This work was supported by funding from Hanyang University, Brain Korea 21 Plus (BK21+), The Korean Electrochemical Society (KECS), LG Chem, ECOPRO, Umicore, and Malvern PANalytical. We are most grateful to the invited speakers and ICAC staff, especially Hwa-Jin Lee, and all participants who made this forum truly fruitful. All of the photographs in Figures 1−4 were taken and arranged by Won-Jin Kwak, who is the author of this paper.

(1) U.S. DOE. EV Everywhere Grand Challenge Blueprint; U.S. Department of Energy: Washington, DC, 2013. (2) Thackeray, M. M.; Wolverton, C.; Isaacs, E. D. Electrical Energy Storage for Transportation  Approaching the Limits Of, and Going Beyond, Lithium-Ion Batteries. Energy Environ. Sci. 2012, 5, 7854− 7863. (3) Blomgren, G. E. The Development and Future of Lithium Ion Batteries. J. Electrochem. Soc. 2017, 164, A5019−A5025. (4) Etacheri, V.; Marom, R.; Elazari, R.; Salitra, G.; Aurbach, D. Challenges in the Development of Advanced Li-Ion Batteries: A Review. Energy Environ. Sci. 2011, 4, 3243−3262. (5) Kostecki, R.; McLarnon, F. Local-Probe Studies of Degradation of Composite LiNi0.8Co0.15Al0.05O2 Cathodes in High-Power Lithium-Ion Cells. Electrochem. Solid-State Lett. 2004, 7, A380−A383. (6) Itou, Y.; Ukyo, Y. Performance of LiNiCoO2 Materials for Advanced Lithium-Ion Batteries. J. Power Sources 2005, 146, 39−44. (7) Myung, S.-T.; Maglia, F.; Park, K.-J.; Yoon, C. S.; Lamp, P.; Kim, S.-J.; Sun, Y.-K. Nickel-Rich Layered Cathode Materials for Automotive Lithium-Ion Batteries: Achievements and Perspectives. ACS Energy Lett. 2017, 2, 196−223. (8) Watanabe, S.; Kinoshita, M.; Hosokawa, T.; Morigaki, K.; Nakura, K. Capacity Fade of LiAlyNi1‑x‑yCoxO2 Cathode for Lithium-Ion Batteries During Accelerated Calendar and Cycle Life Tests (Surface Analysis of LiAlyNi1‑x‑yCoxO2 Cathode after Cycle Tests in Restricted Depth of Discharge Ranges). J. Power Sources 2014, 258, 210−217. (9) Shim, J.; Kostecki, R.; Richardson, T.; Song, X.; Striebel, K. A. Electrochemical Analysis for Cycle Performance and Capacity Fading of a Lithium-Ion Battery Cycled at Elevated Temperature. J. Power Sources 2002, 112, 222−230. (10) Noh, H.-J.; Youn, S.; Yoon, C. S.; Sun, Y.-K. Comparison of the Structural and Electrochemical Properties of Layered Li[NixCoyMnz]O2 (x = 1/3, 0.5, 0.6, 0.7, 0.8, and 0.85) Cathode Material for LithiumIon Batteries. J. Power Sources 2013, 233, 121−130. (11) Yoon, C. S.; Choi, M. H.; Lim, B.-B.; Lee, E.-J.; Sun, Y.-K. HighCapacity Li[Ni1‑xCox/2Mnx/2]O2 (x = 0.1, 0.05, 0) Cathodes for NextGeneration Li-Ion Battery. J. Electrochem. Soc. 2015, 162, A2483− A2489. (12) Sun, Y.-K.; Chen, Z.; Noh, H.-J.; Lee, D.-J.; Jung, H.-G.; Ren, Y.; Wang, S.; Yoon, C. S.; Myung, S.-T.; Amine, K. Nanostructured HighEnergy Cathode Materials for Advanced Lithium Batteries. Nat. Mater. 2012, 11, 942−947. (13) Park, K.-J.; Jung, H.-G.; Kuo, L.-Y.; Kaghazchi, P.; Yoon, C. S.; Sun, Y.-K. Improved Cycling Stability of Li[Ni0.90Co0.05Mn0.05]O2 Through Microstructure Modification by Boron Doping for Li-Ion Batteries. Adv. Energy Mater. 2018, 8, 1801202. (14) Park, K.-J.; Choi, M.-J.; Maglia, F.; Kim, S.-J.; Kim, K.-H.; Yoon, C. S.; Sun, Y.-K. High-Capacity Concentration Gradient Li[Ni0.865Co0.120Al0.015]O2 Cathode for Lithium-Ion Batteries. Adv. Energy Mater. 2018, 8, 1703612. (15) Lee, J. H.; Yoon, C. S.; Hwang, J.-Y.; Kim, S.-J.; Maglia, F.; Lamp, P.; Myung, S.-T.; Sun, Y.-K. High-Energy-Density Lithium-Ion Battery Using a Carbon-Nanotube-Si Composite Anode and a Compositionally Graded Li[Ni0.85Co0.05Mn0.10]O2 Cathode. Energy Environ. Sci. 2016, 9, 2152−2158. (16) Kim, U.-H.; Lee, E.-J.; Yoon, C. S.; Myung, S.-T.; Sun, Y.-K. Compositionally Graded Cathode Material with Long-Term Cycling

Figure 3. Prof. Claude Delmas giving thanks to the delegates at the conference banquet.

Figure 4. Staff for the ICAC 2018 wearing T-shirts provided by ACS Energy Letters.

experience of the first ICAC, we plan to hold an even more valuable conference with programs that will be beneficial to both academia and industry. We hope that the second ICAC will be a significant opportunity for many researchers who are interested in secondary batteries. It would be a pleasure to meet again at ICAC 2019.

Won-Jin Kwak Nam-Yung Park Yang-Kook Sun*

■

Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Won-Jin Kwak: 0000-0002-9807-1434 Nam-Yung Park: 0000-0002-7626-5801 Yang-Kook Sun: 0000-0002-0117-0170 Notes

Views expressed in this Energy Focus are those of the authors and not necessarily the views of the ACS. The authors declare no competing financial interest. 2759

DOI: 10.1021/acsenergylett.8b01926 ACS Energy Lett. 2018, 3, 2757−2760

Energy Focus

ACS Energy Letters Stability for Electric Vehicle Applications. Adv. Energy Mater. 2016, 6, 1601417. (17) Kim, U.-H.; Jun, D.-W.; Park, K.-J.; Zhang, Q.; Kaghazchi, P.; Aurbach, D.; Major, D. T.; Goobes, G.; Dixit, M.; Leifer, N.; et al. Pushing the Limit of Layered Transition Metal Oxide Cathodes for High-Energy-Density Rechargeable Li-Ion Batteries. Energy Environ. Sci. 2018, 11, 1271−1279. (18) Delmas, C.; Fouassier, C.; Hagenmuller, P. Structural Classification and Properties of Layered Oxides. Physica B+C 1980, 99, 81−85. (19) Guilmard, M.; Pouillerie, C.; Croguennec, L.; Delmas, C. Structural and Electrochemical Properties of LiNi0.70Co0.15Al0.15O2. Solid State Ionics 2003, 160, 39−50. (20) Ando, K.; Yamada, Y.; Nishikawa, K.; Matsuda, T.; Imamura, D.; Kanamura, K. Degradation Analysis of LiNi0.8Co0.15Al0.05O2 for Cathode Material of Lithium-Ion Battery using Single-Particle Measurement. ACS Appl. Energy Mater. 2018, 1, 4536. (21) Hou, P.; Zhang, H.; Zi, Z.; Zhang, L.; Xu, X. Core-Shell and Concentration-Gradient Cathodes Prepared via Co-Precipitation Reaction for Advanced Lithium-Ion Batteries. J. Mater. Chem. A 2017, 5, 4254−4279. (22) Jo, C.-H.; Cho, D.-H.; Noh, H.-J.; Yashiro, H.; Sun, Y.-K.; Myung, S. T. An Effective Method to Reduce Residual Lithium Compounds on Ni-Rich Li[Ni0.6Co0.2Mn0.2]O2 Active Material Using a Phosphoric Acid Derived Li3PO4 Nanolayer. Nano Res. 2015, 8, 1464− 1479. (23) Kim, J.-M.; Kim, J. A.; Kim, S.-H.; Uhm, I. S.; Kang, S. J.; Kim, G.; Lee, S.-Y.; Yeon, S.-H.; Lee, S.-Y. All-Nanomat Lithium-Ion Batteries: A New Cell Architecture Platform for Ultrahigh Energy Density and Mechanical Flexibility. Adv. Mater. 2017, 7, 1701099. (24) Shin, B. R.; Nam, Y. J.; Kim, J. W.; Lee, Y.-G.; Jung, Y. S. Interfacial Architecture for Extra Li+ Storage in All-Solid-State Lithium Batteries. Sci. Rep. 2015, 4, 5572. (25) Zhao, W.; Zheng, J.; Zou, L.; Jia, H.; Liu, B.; Wang, H.; Engelhard, M. H.; Wang, C.; Xu, W.; Yang, Y.; Zhang, J.-G. High Voltage Operation of Ni-Rich NMC Cathodes Enabled by Stable Electrode Electrolyte Interphases. Adv. Energy Mater. 2018, 8, 1800297. (26) Yan, P.; Zheng, J.; Liu, J.; Wang, B.; Cheng, X.; Zhang, Y.; Sun, X.; Wang, C.; Zhang, J.-G. Tailoring Grain Boundary Structures and Chemistry of Ni-Rich Layered Cathodes for Enhanced Cycle Stability of Lithium-Ion Batteries. Nat. Energy 2018, 3, 600−605. (27) Lee, W.; Muhammad, S.; Kim, T.; Kim, H.; Lee, E.; Jeong, M.; Son, S.; Ryou, J.-H.; Yoon, W.-S. New Insight into Ni-Rich Layered Structure for Next-Generation Li Rechargeable Batteries. Adv. Energy Mater. 2018, 8, 1701788. (28) Office of Technology Transitions. Battery500 Consortium to Spark EV Innovations: Pacific Northwest National Laboratory-led, 5-Year $50M Effort Seeks to Almost Triple Energy Stored in Electric Car Batteries. https://www.energy.gov/technologytransitions/articles/battery500consortium-spark-ev-innovations-pacific-northwest-national (accessed September 2018). (29) Zheng, J.; Xu, P.; Gu, M.; Xiao, J.; Browning, N. D.; Yan, P.; Wang, C.; Zhang, J.-G. Structural and Chemical Evolution of Li- and Mn-Rich Layered Cathode Material. Chem. Mater. 2015, 27, 1381− 1390. (30) Zhang, H.; May, B. M.; Serrano-Sevillano, J.; Casas-Cabanas, M.; Cabana, J.; Wang, C.; Zhou, G. Facet-Dependent Rock-Salt Reconstruction on the Surface of Layered Oxide Cathodes. Chem. Mater. 2018, 30, 692−699. (31) Shi, Q.; Heng, S.; Qu, Q.; Gao, T.; Liu, W.; Hang, L.; Zheng, H. Constructing an Elastic Solid Electrolyte Interphase on Graphite: A Novel Strategy Suppressing Lithium Inventory Loss in Lithium-Ion Batteries. J. Mater. Chem. A 2017, 5, 10885−10894. (32) Lin, F.; Markus, I. M.; Nordlund, D.; Weng, T.-C.; Asta, M. D.; Xin, H. L.; Doeff, M. M. Surface Reconstruction and Chemical Evolution of Stoichiometric Layered Cathode Materials for LithiumIon Batteries. Nat. Commun. 2014, 5, 3529.

(33) Kang, J.; Han, B. First Principles Study on the Thermal Stability of LiNiO2 Materials Coated by Amorphous Al2O3 with Atomic Layer Thickness. ACS Appl. Mater. Interfaces 2015, 7, 11599−11603. (34) Liu, H.; Liu, H.; Seymour, I. D.; Chernova, N.; Wiaderek, K. M.; Trease, N. M.; Hy, S.; Chen, Y.; An, K.; Zhang, M.; et al. Identifying the Chemical and Structural Irreversibility in LiNi0.8Co0.15Al0.05O2  A Model Compound for Classical Layered Intercalation. J. Mater. Chem. A 2018, 6, 4189−4198. (35) Lee, I.; Kim, J.; Han, S.; Park, J.-I.; Lee, J.-M.; Kim, D.-H.; Nam, S.-C.; Yoon, S. Preparation of Highly Monodisperse Ni-Rich Cathode Material for Lithium Ion Batteries. J. Electrochem. Soc. 2016, 163, A1336−A1339. (36) Scrosati, B.; Garche, J. Lithium Batteries: Status, Prospects, and Future. J. Power Sources 2010, 195, 2419−2430. (37) Jiao, S.; Ren, X.; Cao, R.; Engelhard, M. H.; Liu, Y.; Hu, D.; Mei, D.; Zheng, J.; Zhao, W.; Li, Q.; et al. Stable Cycling of High-Voltage Lithium Metal Batteries in Ether Electrolytes. Nat. Energy 2018, 3, 739−746. (38) Hwang, S.; Chang, W.; Kim, S. M.; Su, D.; Kim, D. H.; Lee, J. Y.; Chung, K. Y.; Stach, E. A. Investigation of Changes in the Surface Structure of LixNi0.8Co0.15Al0.05O2 Cathode Materials Induced by the Initial Charge. Chem. Mater. 2014, 26, 1084−1092. (39) Komaba, S.; Kumagai, N.; Kato, K.; Yashiro, H. Hydrothermal Synthesis of Hexagonal Tungsten Trioxide from Li2WO4 Solution and Electrochemical Lithium Intercalation into the Oxide. Solid State Ionics 2000, 135, 193−197. (40) Yoon, C. S.; Kim, U.-H.; Park, G.-T.; Kim, S. J.; Kim, K.-H.; Kim, J.; Sun, Y.-K. Self-Passivation of a LiNiO2 Cathode for a Lithium-Ion Battery through Zr Doping. ACS Energy Lett. 2018, 3, 1634−1639. (41) Hu, P.; Zhao, J.; Wang, T.; Shang, C.; Zhang, J.; Qin, B.; Liu, Z.; Xiong, J.; Cui, G. A Composite Gel Polymer Electrolyte with High Voltage Cyclability for Ni-Rich Cathode of Lithium-Ion Battery. Electrochem. Commun. 2015, 61, 32−35. (42) Kim, H.; Lee, S.; Park, Y.-U.; Kim, H.; Kim, J.; Jeon, S.; Kang, K. Neutron and X-ray Diffraction Study of Pyrophosphate-Based Li2‑xMP2O7 (M = Fe, Co) for Lithium Rechargeable Battery Electrodes. Chem. Mater. 2011, 23, 3930−3937. (43) Han, J.-G.; Lee, J. B.; Cha, A.; Lee, T. K.; Cho, W.; Chae, S.; Kang, S. J.; Kwak, S. K.; Cho, J.; Hong, S. Y.; Choi, N.-S. Unsymmetrical Fluorinated Malonatoborate as an Amphoteric Additive for HighEnergy-Density Lithium-Ion Batteries. Energy Environ. Sci. 2018, 11, 1552−1562.

2760

DOI: 10.1021/acsenergylett.8b01926 ACS Energy Lett. 2018, 3, 2757−2760