文献类型：期刊文献

英文题名：Low-Valence Mg2+ Doping Suppresses Irreversible Phase Transition of Sodium-Rich Fluorophosphate upon Additional Na+ Deintercalation

作者：Ren, Ketai[1];Qiu, Jinkai[1];Liu, Honglai[1,2];Song, Hongfang[3];Li, Quan[3];Li, Jingkun[1]

机构：[1]East China Univ Sci & Technol, Sch Chem & Mol Engn, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Sch Chem Engn, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[3]Shanghai Xiangfenghua Technol Co Ltd, Shanghai 200949, Peoples R China

年份：2025

卷号：8

期号：5

起止页码：3066

外文期刊名：ACS APPLIED ENERGY MATERIALS

收录：;EI(收录号：20250917955342);WOS:【SCI-EXPANDED(收录号:WOS:001433483000001)】；

基金：This work was financially supported by the open Foundation of Shanghai Jiao Tong University Shaoxing Research Institute of Renewable Energy and Molecular Engineering (No. JDSX2022013).

语种：英文

外文关键词：sodium-ion battery; sodium-rich fluorophosphate; magnesium doping; Na+ extraction/insertion; phase transition

摘要：Fluorophosphate Na3V2(PO4)(2)F-3 (NVPF) is considered a promising cathode material for sodium-ion batteries, while its specific capacity is still insufficient compared to that of cathodes of lithium-ion batteries. Activating the third Na+ effectively increases the specific capacity of NVPF. However, the accompanied irreversible phase transition deteriorates the cycling stability. In this study, we synthesized sodium-rich Na3.5V1.5Mg0.5(PO4)(2)F-3 (NVMPF) through doping low-valence Mg2+ with a high content, which introduces an extra 0.5 Na+ in the crystal lattice. The extra 0.5 Na+ remains in the lattice of NVMPF, acting as "pillars" to suppress the irreversible phase transition after the third Na+ is extracted by activating the V5+/4+ redox couple at a high voltage. Thus, NVMPF achieves a specific discharge capacity of 170 mAh g(-1) between 1.0 and 4.7 V while maintaining the tetragonal structure of NVMPF. This work offers insightful guidelines to achieve the full utilization of three Na+ with enhanced cycling stability.