Affiliation:
1. State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 P. R. China
2. CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 P. R. China
3. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China
Abstract
AbstractTransition metal layered oxides (NaxTMO2), boasting a high theoretical specific capacity and affordability, have emerged as prominent cathodes for sodium‐ion batteries (SIBs). Their potential, however, is hindered when operating at higher voltage range (4.0–4.3 V) due to irreversible phase transition, heterogeneous surface reconstruction, and side reaction. Herein, using a straightforward room‐temperature liquid‐phase reductive method, a dual conformal protective layer is in situ constructed on the surface of NaNi1/3Fe1/3Mn1/3O2(NFM). This layer comprises both a spinel structure and an amorphous CoxB coating, thereby achieving a layered‐spinel‐CoxB configuration. The spinel structure provides 3D Na+ transport channels and works as a pillar to anchor the intrinsic layered structure. Simultaneously, the external CoxB layer effectively mitigates O loss, transition metal ion dissolution, and undesired side reactions on the surface. Benefiting from the synergistic effects on both the material's bulk and surface, the 1wt% CoxB coated cathode displays superior stability. After 300 cycles, the capacity retention is 79.6% between 2 and 4 V, significantly outperforming pristine‐NFM's(p‐NFM) 51.4%. When charged to 4.3 V, its capacity retention stands at 70%, much higher than that of p‐NFM (51.2%). This work provides new insights into exploiting high‐voltage stable cathode through constructing a dual conformal protective layer for high energy density SIBs.
Funder
National Natural Science Foundation of China
Subject
General Materials Science,Renewable Energy, Sustainability and the Environment