TY - JOUR AU - Zengqing Zhuo AU - Kehua Dai AU - Jinpeng Wu AU - Liang Zhang AU - Nobumichi Tamura AU - Yi- de Chuang AU - Jun Feng AU - Jinghua Guo AU - Zhi-xun Shen AU - Gao Liu AU - Feng Pan AU - Wanli Yang AB -

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.

BT - ACS Energy Letters DA - 10/2021 DO - 10.1021/acsenergylett.1c0110110.1021/acsenergylett.1c01101.s001 IS - 10 LA - eng N2 -

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.

PY - 2021 SP - 3417 EP - 3424 ST - ACS Energy Lett. T2 - ACS Energy Letters TI - Distinct Oxygen Redox Activities in Li2MO3 (M = Mn, Ru, Ir) UR - https://pubs.acs.org/doi/10.1021/acsenergylett.1c01101 VL - 6 SN - 2380-8195 ER -