Abstract
Anionic redox chemistry endows Li-rich layered oxide cathode with high specific capacity, but it also causes some critical issues such as voltage decay, structure degradation, and irreversible oxygen release. Herein, we propose to tune both the anionic and cationic redox chemistry of Li1.2Mn0.6Ni0.2O2 via a "three-in-one"strategy integrating Na doping for the Li site and Si substitution for the Mn and Na2SiO3 coating layer, which is achieved by the facile coating of Na+-conductive Na2SiO3. In comparison with the pristine or Li2SiO3-coating sample, the concerns of voltage fading, poor rate capability, structure degradation, and oxygen release have all been largely alleviated due to the "three-in-one"effect. First, the coating layer impedes the side reaction and the dissolution of transition metals (TMs). Second, Na+ is confirmed to be doped into the Li layers to facilitate the transport kinetics of lithium ions while Si4+ is doped into the TM site, which enhances the stability of the layered structure during cycling due to the strong Si-O bond and reduces the migration of TMs. Third, the integrated strategy also decreases the covalency of TM-O bonds, which is verified to improve the reversibility of anion redox chemistry and suppress oxygen evolution. The synergetic strategy sheds some light on exploring high-performance cathode materials by tuning both anionic and cationic redox chemistry.
| Original language | English |
|---|---|
| Pages (from-to) | 9404-9414 |
| Number of pages | 11 |
| Journal | Chemistry of Materials |
| Volume | 32 |
| Issue number | 21 |
| DOIs | |
| State | Published - Nov 10 2020 |
Funding
This work was supported by International Partnership Program (grant no. 211211KYSB20170060) of the Chinese Academy of Sciences the National Natural Science Foundation of China (grant no. 11575192 and 11975238), the Scientific Instrument Developing Project (grant no. ZDKYYQ20170001), and the Strategic Priority Research Program (grant no. XDB28000000) of the Chinese Academy of Sciences, and Natural Science Foundation of Beijing (grant no. 2182082). This work was also supported by the Fundamental Research Funds for the Central Universities. The neutron experiments benefit from the SNS user facilities (VULCAN beamline) sponsored by the office of Basic Energy Sciences (BES), the Office of Science of the U.S. DOE. The authors also thank the staffs at the KMC2 and U41-PEAXIS beamlines at BESSY-II, HZB, Germany. This work was supported by International Partnership Program (grant no. 211211KYSB20170060) of the Chinese Academy of Sciences, the National Natural Science Foundation of China (grant no. 11575192 and 11975238), the Scientific Instrument Developing Project (grant no. ZDKYYQ20170001), and the Strategic Priority Research Program (grant no. XDB28000000) of the Chinese Academy of Sciences, and Natural Science Foundation of Beijing (grant no. 2182082). This work was also supported by the Fundamental Research Funds for the Central Universities. The neutron experiments benefit from the SNS user facilities (VULCAN beamline) sponsored by the office of Basic Energy Sciences (BES), the Office of Science of the U.S. DOE. The authors also thank the staffs at the KMC2 and U41-PEAXIS beamlines at BESSY-II, HZB, Germany.
| Funders | Funder number |
|---|---|
| Scientific Instrument Developing Project | ZDKYYQ20170001 |
| Strategic Priority Research Program | XDB28000000 |
| U.S. DOE | |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | |
| National Natural Science Foundation of China | 11575192, 11975238 |
| Chinese Academy of Sciences | |
| Natural Science Foundation of Beijing Municipality | 2182082 |
| Fundamental Research Funds for the Central Universities |