文献类型：期刊文献

英文题名：Effects of Triple Modification?Of Sodium Hypophosphite on Structure and Electrochemical Performances of Lithium-Rich Manganese-Based Cathode Materials

作者：Li, Heng[1]; Cao, Shuang[1]; Li, Zhi[1]; Wu, Chao[1]; Chen, Jiarui[1]; Guo, Xiaowei[2]; Chang, Baobao[3]; Wang, Xianyou[1]

第一作者：Li, Heng

机构：[1] National Base for International Science & Technology Cooperation, National Local Joint Engineering Laboratory for Key Materials of New Energy Storage Battery, Hunan Province Key Laboratory of Electrochemical Energy Storage & Conversion, School of Chemistry, Xiangtan University, Xiangtan, 411105, China; [2] School of Chemistry & Materials Engineering, Xinxiang University, Henan, 453003, China; [3] Key Laboratory of Materials Processing, Mold of Ministry of Education, Zhengzhou University, Henan, 450001, China

第一机构：National Base for International Science & Technology Cooperation, National Local Joint Engineering Laboratory for Key Materials of New Energy Storage Battery, Hunan Province Key Laboratory of Electrochemical Energy Storage & Conversion, School of Chemistry, Xiangtan University, Xiangtan, 411105, China

年份：2022

外文期刊名：SSRN

收录：EI(收录号：20220117122)

语种：英文

外文关键词：Lithium - Lithium compounds - Manganese - Manganese compounds - Metal ions - Nickel compounds - Oxygen vacancies - Redox reactions - Sodium - Sodium compounds

摘要：Oxygen-anion charge compensation enables lithium-rich manganese-based cathode materials (LRMCs) to possess higher specific capacity than other conventional layered oxide cathode materials. However, irreversible oxygen redox makes LRMCs suffer from the oxygen loss, structure degradation and interfacial reactions, and thus resulting in low initial coulombic efficiency (ICE), poor cyclic stability and rate capacity. In order to suppress the irreversible anionic redox, herein Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) is triply modified with sodium hypophosphite (NaH2PO2) through interfacial reaction. The results show that optimum content of NaH2PO2 is 5 wt%, and the reducing gas PH3 produced by NaH2PO2 decomposition can react with the unstable surface oxygen and transition metal ions to form stable LiTMPO4 protection layer and generate oxygen vacancies, and in the same time Na+ can purposely be doped into the Li position of LMNCO. Accordingly, the electrochemical performance of the surface-treated LMNCO-NP 5% is distinctly improved. It has been found that LMNCO-NP 5% displays an ICE of 88.94%, which is much higher than untreated LMNCO (78.2%). Meanwhile, the capacity retentions of LMNCO-NP 5% at 1 C and 5 C after 100 cycles are 94.85% and 78.45%, respectively. Therefore, the triple modification strategy based on the formation of LiTMPO4 protection layer, generation of oxygen vacancies and Na+ ion surface doping can effectively inhibit the TMs migration and irreversible anionic redox, and thus promoting the electrochemical performances of LRMCs. ? 2022, The Authors. All rights reserved.