Abstract
Solid-state lithium batteries may provide increased energy density and improved safety compared with Li-ion technology. However, in a solid-state composite cathode, mechanical degradation due to repeated cathode volume changes during cycling may occur, which may be partially mitigated by applying a significant, but often impractical, uniaxial stack pressure. Herein, we compare the behavior of composite electrodes based on Li4Ti5O12 (LTO) (negligible volume change) and Nb2O5 (+4% expansion) cycled at different stack pressures. The initial LTO capacity and retention are not affected by pressure but for Nb2O5, they are significantly lower when a stack pressure of <2 MPa is applied, due to inter-particle cracking and solid-solid contact loss because of cyclic volume changes. This work confirms the importance of cathode mechanical stability and the stack pressures for long-term cyclability for solid-state batteries. This suggests that low volume-change cathode materials or a proper buffer layer are required for solid-state batteries, especially at low stack pressures.
Original language | English |
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Pages (from-to) | 721-728 |
Number of pages | 8 |
Journal | SusMat |
Volume | 3 |
Issue number | 5 |
DOIs | |
Publication status | Published - 8 Oct 2023 |
Bibliographical note
Acknowledgments:Peter G. Bruce is indebted to the Henry Royce Institute SOLBAT (FIRG007 and FIRG008), as well as the Engineering and Physical Sciences Research Council, Enabling Next Generation Lithium Batteries (EP/M009521/1), and the Henry Royce Institute for Advanced Materials (EP/R0066X/1, EP/S019367/1, and EP/R010145/1) for financial support. Xiangwen Gao acknowledges financial support from the National Natural Science Foundation of China (22309110).
Keywords
- cathode
- interface
- mechanical degradation
- stack pressure
- solid-state battery