| Title | Metal-Ligand pi Interactions in Lithium-Rich Li2RhO3 Cathode Material Activate Bimodal Anionic Redox |
| Authors | Zhang, Kun Jiang, Zewen Ning, Fanghua Li, Biao Shang, Huaifang Song, Jin Zuo, Yuxuan Yang, Tonghuan Feng, Guang Ai, Xinping Xia, Dingguo |
| Affiliation | Peking Univ, Sch Mat Sci & Engn, Beijing Key Lab Theory & Technol Adv Battery Mat, Beijing 100871, Peoples R China Wuhan Univ, Coll Chem & Mol Sci, Wuhan 430072, Peoples R China |
| Keywords | OXYGEN-REDOX LAYERED OXIDES CAPACITY HYSTERESIS ELECTROCHEMISTRY ABSORPTION STABILITY CHEMISTRY |
| Issue Date | Jun-2021 |
| Publisher | ADVANCED ENERGY MATERIALS |
| Abstract | Li-rich oxide (LRO) cathodes that exhibit anionic redox activity can boost the energy density of Li-ion batteries. Oxygen redox in LROs can originate from the charge compensation of pure O 2p nonbonding (NB) states; however, the high charging voltages cause much safety concerns in practical applications. Exploiting new anionic redox modes that can be used at low voltages is thus imperative. In view of this, a further understanding of the anionic redox behavior with respect to metal-ligand interactions in LROs is highly desired. In this study, by analyzing the orbital combinations of transition metals (TMs) and O in LROs, the prevalence of pi-type, sigma-type, and NB states is investigated. Highly covalent Li2RhO3 with strong pi-type interactions is selected as a model material. Owing to the closer energy levels of O and Rh and the orbital vacancy of Rh-4, oxygen acts as a pi-electron donor to central Rh and exhibits high reactivity in the occupied anti-bonding state, showing a novel low-voltage O redox which is distinct from high-voltage NB O redox. This pi-type oxygen redox mode expands the fundamental theories of anionic redox and provides a new design route to achieve high-capacity Li-rich cathode materials. |
| URI | http://hdl.handle.net/20.500.11897/617987 |
| ISSN | 1614-6832 |
| DOI | 10.1002/aenm.202100892 |
| Indexed | SCI(E) |
| Appears in Collections: | 数学科学学院 先进电池材料料理论与技术北京市重点实验室 |
