Cu-N Synergism Regulation to Enhance Anionic Redox Reversibility and Activity of Li- and Mn-Rich Layered Oxides Cathode

Zhijun Wu; Chenhui Yan; Panyu Gao; Liaona She; Xin Zhang; Yue Lin; Xuebin Yu; Yongfeng Liu; Wenping Sun; Yinzhu Jiang; Yaxiong Yang; Mingxia Gao; Hongge Pan

doi:10.1002/smll.202401645

Cu-N Synergism Regulation to Enhance Anionic Redox Reversibility and Activity of Li- and Mn-Rich Layered Oxides Cathode

Small. 2024 May 19:e2401645. doi: 10.1002/smll.202401645. Online ahead of print.

Authors

Zhijun Wu¹, Chenhui Yan^{1

2}, Panyu Gao³, Liaona She¹, Xin Zhang², Yue Lin⁴, Xuebin Yu³, Yongfeng Liu², Wenping Sun², Yinzhu Jiang², Yaxiong Yang¹, Mingxia Gao², Hongge Pan^{1

2}

Affiliations

¹ Institute of Science and Technology for New Energy, Xi'an Technological University, Xi'an, 710021, China.
² State Key Laboratory of Silicon and Advanced Semiconductor Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
³ Department of Materials Science, Fudan University, Shanghai, 200433, China.
⁴ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China.

PMID: 38764309
DOI: 10.1002/smll.202401645

Abstract

Anionic redox chemistry enables extraordinary capacity for Li- and Mn-rich layered oxides (LMROs) cathodes. Unfortunately, irreversible surface oxygen evolution evokes the pernicious phase transition, structural deterioration, and severe electrode-electrolyte interface side reaction with element dissolution, resulting in fast capacity and voltage fading of LMROs during cycling and hindering its commercialization. Herein, a redox couple strategy is proposed by utilizing copper phthalocyanine (CuPc) to address the irreversibility of anionic redox. The Cu-N synergistic effect of CuPc could not only inhibit surface oxygen evolution by reducing the peroxide ion O₂ ^2- back to lattice oxygen O^2-, but also enhance the reaction activity and reversibility of anionic redox in bulk to achieve a higher capacity and cycling stability. Moreover, the CuPc strategy suppresses the interface side reaction and induces the forming of a uniform and robust LiF-rich cathode electrolyte, interphase (CEI) to significantly eliminate transition metal dissolution. As a result, the CuPc-enhanced LMRO cathode shows superb cycling performance with a capacity retention of 95.0% after 500 long-term cycles. This study sheds light on the great effect of N-based redox couple to regulate anionic redox behavior and promote the development of high energy density and high stability LMROs cathode.

Keywords: Cu‐N synergism; Li‐ and Mn‐rich layered oxide; copper phthalocyanine; cycling stability; redox couple.