Abstract
High-voltage LiCoO2 (LCO) attracts great interest because of its large specific capacity, but it suffers from oxygen release, structural degradation, and quick capacity drop. These daunting issues root from the inferior thermodynamics and kinetics of the triggered oxygen anion redox (OAR) at high voltages. Herein, a tuned redox mechanism with almost only Co redox is demonstrated by atomically engineered high-spin LCO. The high-spin Co network reduces the Co/O band overlap, eliminates the adverse phase transition of O3 → H1-3, delays the exceeding of the O 2p band over the Fermi level, and suppresses excessive O → Co charge transfer at high voltages. This function intrinsically promotes Co redox and restrains O redox, fundamentally addressing the issues of O2 release and coupled detrimental Co reduction. Moreover, the chemomechanical heterogeneity caused by different kinetics of Co/O redox centers and the inferior rate performance limited by slow O redox kinetics is simultaneously improved owing to the suppression of slow OAR and the excitation of fast Co redox. The modulated LCO delivers ultrahigh rate capacities of 216 mAh g-1 (1C) and 195 mAh g-1(5C), as well as high capacity retentions of 90.4% (@100 cycles) and 86.9% (@500 cycles). This work sheds new light on the design for a wide range of O redox cathodes.
| Original language | English |
|---|---|
| Pages (from-to) | 10208-10219 |
| Number of pages | 12 |
| Journal | Journal of the American Chemical Society |
| Volume | 145 |
| Issue number | 18 |
| DOIs | |
| State | Published - May 10 2023 |
Funding
This work was supported by the National Natural Science Foundation of China (Grant Nos. 22005302, 11975238, and 11575192), the International Partnership Program (Grant Nos. 211211KYSB20170060 and 211211KYSB20180020), the Scientific Instrument Developing Project (Grant No. ZDKYYQ20170001), the Strategic Priority Research Program (Grant No. XDB28000000) of the Chinese Academy of Sciences, and the Natural Science Foundation of Beijing (Grant No. 2182082). This work was also supported by the China Postdoctoral Science Foundation (2020M680648) and the Fundamental Research Funds for the Central Universities. The authors thank the staff from the BL14W1 beamline and 02B02 beamline of SSRF for their help and support. The authors also thank the staff from the PEAXIS beamline of synchrotron BESSY II at Helmholtz-Zentrum Berlin (HZB). This work was supported by the National Natural Science Foundation of China (Grant Nos. 22005302, 11975238, and 11575192), the International Partnership Program (Grant Nos. 211211KYSB20170060 and 211211KYSB20180020), the Scientific Instrument Developing Project (Grant No. ZDKYYQ20170001), the Strategic Priority Research Program (Grant No. XDB28000000) of the Chinese Academy of Sciences, and the Natural Science Foundation of Beijing (Grant No. 2182082). This work was also supported by the China Postdoctoral Science Foundation (2020M680648) and the Fundamental Research Funds for the Central Universities. The authors thank the staff from the BL14W1 beamline and 02B02 beamline of SSRF for their help and support. The authors also thank the staff from the PEAXIS beamline of synchrotron BESSY II at Helmholtz–Zentrum Berlin (HZB).