Sandwich structure endows Na3V2(PO4)3 cathodes with superb sodium storage

• Published in: Applied physics letters Vol. 121; no. 11
• Main Authors: Gao, Fengjie, Chen, Di, Yang, Hui Ying, Yin, Yanfeng, Yu, Caiyan, Bai, Ying
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 12-09-2022
• Subjects: Applied physics; Cathodes; Conductors; Electrochemical analysis; Electrodes; Performance degradation; Sandwich structures; Sodium; Sodium-ion batteries; Structural stability; Synergistic effect
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0100982

Na3V2(PO4)3 (NVP) is a promising cathode for high-energy density sodium-ion batteries, whereas its electrochemical performance is also degraded by its intrinsically inferior electronic conductivity and interfacial side reactions. Herein, Li+, Al3+, and Ti4+ ions were incorporated into the near-surface, and NVP particles were encapsulated by a solid Na+ superionic conductor electrolyte Li1.4Al0.4Ti1.6(PO4)3 (LATP) and carbon (C). Typically, the 0.2 wt. % LATP/C-modified NVP electrode delivers a high initial discharge capacity of 91.22 mA h g−1 and a remarkable rate performance of 56.5 mA h g−1 (20 C). Intensive explorations manifest that the significant improvement in the electrochemical performance of NVP/C could be attributed to the synergistic effects of Li+, Al3+, and Ti4+ doping and the characteristic NVP/LATP/C sandwich coating structure. The modification strategy established in this work synchronously enhanced the electronic conductivity and structural stability of NVP, and this study also provides insight into well-designed electrode microstructures in high-performance batteries.