%0 Journal Article %A Zengqing Zhuo %A Kehua Dai %A Jinpeng Wu %A Liang Zhang %A Nobumichi Tamura %A Yi- de Chuang %A Jun Feng %A Jinghua Guo %A Zhi-xun Shen %A Gao Liu %A Feng Pan %A Wanli Yang %B ACS Energy Letters %D 2021 %G eng %N 10 %P 3417 - 3424 %R 10.1021/acsenergylett.1c0110110.1021/acsenergylett.1c01101.s001 %T Distinct Oxygen Redox Activities in Li2MO3 (M = Mn, Ru, Ir) %U https://pubs.acs.org/doi/10.1021/acsenergylett.1c01101 %V 6 %8 10/2021 %! ACS Energy Lett. %X

Li₂MO₃ (M = transition metal) systems are parent compounds of Li-rich materials and widely considered to offer oxygen redox for high-energy batteries. However, recent clarifications have revealed that, among the three representative Li₂MO₃ (M = Mn, Ru, Ir) compounds, no reversible oxygen redox takes place in the Mn and Ir systems. Here, we reevaluate the redox reactions in Li₂RuO₃ through advanced spectroscopy, which shows both Ru redox and highly reversible O redox (96% initial-cycle reversibility, 80% retained after 10 cycles, and 77% after 50 cycles). This is in sharp contrast with the Li₂MnO₃ and Li₂IrO₃ systems and concludes the three distinct oxygen behaviors in the Li₂MO₃ systems during charging: (i) only irreversible oxygen oxidation in Li₂MnO₃; (ii) reversible Ru and O redox in Li₂RuO₃; (iii) only cationic redox in Li₂IrO₃. This work suggests the critical role of transition metals and their coupling to oxygen for maintaining reversible oxygen redox activities for high-energy batteries.