Affiliation:
1. School of Chemical Engineering Sichuan University Chengdu 610065 P. R. China
2. Institute for Carbon Neutralization College of Chemistry and Materials Engineering Wenzhou University Wenzhou 325035 P. R. China
3. Wenzhou Key Laboratory of Sodium‐Ion Batteries Wenzhou University Technology Innovation Institute for Carbon Neutralization Wenzhou 325035 China
4. Institute of Energy Materials Science University of Shanghai for Science and Technology Shanghai 200093 P. R. China
Abstract
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.
Funder
National Natural Science Foundation of China
State Key Laboratory of Polymer Materials Engineering
Science and Technology Department of Sichuan Province
Natural Science Foundation of Zhejiang Province
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science