Formulating Local Environment of Oxygen Mitigates Voltage Hysteresis in Li‐Rich Materials

• DOI: 10.1002/adma.202311814
• Publication Date: 2024-01-09T16:03:29Z
• Authors: Mengke Zhang; Lang Qiu; Weibo Hua; Yang Song; Yuting Deng; Zhenguo Wu; Yanfang Zhu; Benhe Zhong; Shulei Chou; Shixue Dou; Yao Xiao; Xiaodong Guo
• Keywords: 01 natural sciences; 0104 chemical sciences

AbstractLi‐rich cathode materials have emerged as one of the most prospective options for Li‐ion batteries owing to their remarkable energy density (>900 Wh kg−1). However, voltage hysteresis during charge and discharge process lowers the energy conversion efficiency, which hinders their application in practical devices. Herein, the fundamental reason for voltage hysteresis through investigating the O redox behavior under different (de)lithiation states is unveiled and it is successfully addressed by formulating the local environment of O2−. In Li‐rich Mn‐based materials, it is confirmed that there exists reaction activity of oxygen ions at low discharge voltage (<3.6 V) in the presence of TM‐TM‐Li ordered arrangement, generating massive amount of voltage hysteresis and resulting in a decreased energy efficiency (80.95%). Moreover, in the case where Li 2b sites are numerously occupied by TM ions, the local environment of O2− evolves, the reactivity of oxygen ions at low voltage is significantly inhibited, thus giving rise to the large energy conversion efficiency (89.07%). This study reveals the structure–activity relationship between the local environment around O2− and voltage hysteresis, which provides guidance in designing next‐generation high‐performance cathode materials.