Fluorine-substituted O3-type NaNi0.4Mn0.25Ti0.3Co0.05O2-xFx cathode with improved rate capability and cyclic stability for sodium-ion storage at high voltage

• 作者: Chaojin Zhou Lichun Yang Chaogang Zhou Jiangwen Liu Renzong Hu Jun Liu Min Zhu
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（9）
• 页码范围: 341-350
• 页数: 10页
• 语种: 英文

摘要

O3-type NaNiO2-based cathode materials undergo irreversible phase transition and serious capacity decay at high voltage above 4.0 V in sodium-ion batteries.To address these challenges,effects of F-substitution on the structure and electrochemical performance of NaNi0.4Mn0.25Ti0.3Co0.05O2 are investi-gated in this article.The F-substitution leads to expanding of interlayer,which can enhance the mobility of Na+ .NaNi0.4Mn0.25Ti0.3Co0.05O1.92F0.08(NMTC-F0.08)with the optimal F-substitution degree exhibits much improved rate capability and cyclic stability.It delivers reversible capacities of 177 and 97 mAh g-1 at 0.05 and 5 C within 2.0-4.4 V,respectively.Galvanostatic intermittent titration technique verifies faster kinetics of Na+ diffusion in NMTC-F0.08.And in-situ XRD investigation reveals the phase evolution of NMTC-F0.08,indicating enhanced structural stability results from F-substitution.This study may shed light on the development of high performance cathode materials for sodium-ion storage at high voltage.