Xinye Zhao1,Yaosen Tian1,Zhengyan Lun1,Zijian Cai1,Tina Chen1,Bin Ouyang1,Gerbrand Ceder1
University of California, Berkeley1
Xinye Zhao1,Yaosen Tian1,Zhengyan Lun1,Zijian Cai1,Tina Chen1,Bin Ouyang1,Gerbrand Ceder1
University of California, Berkeley1
Cathode materials for Li-ion batteries (LIBs) commonly suffer from chemo-mechanical structural degradation during cycling. The repeated (de-)lithiation processes induce severe volume change and deteriorate the structural integrity of cathode particles, cathode coatings, and the cathode/electrolyte interface [1]. Especially for all-solid-state batteries, solid electrolytes lack the mechanical compliance to tolerate the structural change of the cathode particles. The local expansion and contraction of the cathode particles push the solid electrolyte away, resulting in increased cell impedance and capacity loss [2-4]. Therefore, to improve the capacity retainability and cycle life of all-solid-state Li-ion batteries, it is crucial to develop cathodes that exhibit low volume strain to minimize the structural degradation during cycling. We have used well-calibrated computational techniques to systematically investigate the roles that redox chemistry, structure, disorder, inactive elements, and metal coordination play in determining the volume change of cathode upon delithiation, leading to the exciting conclusion that zero strain compounds are possible. Based on our design rules, we have experimentally synthesized Li<sub>1.3</sub>V<sub>0.4</sub>Nb<sub>0.3</sub>O<sub>2</sub> and Li<sub>1.25</sub>V<sub>0.55</sub>Nb<sub>0.2</sub>O<sub>1.9</sub>F<sub>0.1</sub> with low volume change upon cycling [5]. In this presentation, we will present our established guidelines in detail and discuss the significance of zero-strain for advancing all-solid-state batteries.<br/><br/>Reference:<br/>[1] A.O. Kondrakov, A. Schmidt, J. Xu, H. Geßwein, R. Mönig, P. Hartmann, H. Sommer, T. Brezesinski, J. Janek, Anisotropic Lattice Strain and Mechanical Degradation of High- and Low-Nickel NCM Cathode Materials for Li-Ion Batteries, J. Phys. Chem. C. 121 (2017) 3286–3294.<br/>[2] R. Koerver, I. Aygün, T. Leichtweiß, C. Dietrich, W. Zhang, J.O. Binder, P. Hartmann, W.G. Zeier, J. Janek, Capacity Fade in Solid-State Batteries: Interphase Formation and Chemomechanical Processes in Nickel-Rich Layered Oxide Cathodes and Lithium Thiophosphate Solid Electrolytes, Chem. Mater. 29 (2017) 5574–5582.<br/>[3] R. Koerver, W. Zhang, L. de Biasi, S. Schweidler, A.O. Kondrakov, S. Kolling, T. Brezesinski, P. Hartmann, W.G. Zeier, J. Janek, Chemo-mechanical expansion of lithium electrode materials – on the route to mechanically optimized all-solid-state batteries, Energy Environ. Sci. 11 (2018) 2142–2158.<br/>[4] R. Ruess, S. Schweidler, H. Hemmelmann, G. Conforto, A. Bielefeld, D.A. Weber, J. Sann, M.T. Elm, J. Janek, Influence of NCM Particle Cracking on Kinetics of Lithium-Ion Batteries with Liquid or Solid Electrolyte, J. Electrochem. Soc. 167 (2020) 100532.<br/>[5] X. Zhao, Y. Tian, Z. Lun, Z. Cai, T. Chen, B. Ouyang, G. Ceder, Design principles for zero-strain Li-ion cathodes, Joule. 6 (2022) 1654–1671.