The NASICON-type Na3MnTi(PO4)3 is a promising sodium-ion battery cathode material due to its considerable theoretical specific capacity. However, its practical implementation is hindered by inferior kinetics and a stepwise phase transition. Here, we show a multi-d-electron approach for synthesizing a novel NASICON-type material, Na3.5V0.5Mn0.5Cr0.5Ti0.5(PO4)3, with a delocalized electron system that facilitates electrochemical kinetics and a stable single-phase reaction mechanism with minimal volume change (1.8%). This effectively breaks the performance trade-off among high-rate capability (98.9 mAh g-1 at 40 C), long-term cycling (88.3% after 10,000 cycles at 40 C), and operation over a temperature range of -40 to 50 °C. Importantly, the pouch-type full cell demonstrates its practical feasibility by achieving 85.2% capacity retention after 500 cycles. This study sheds new light on delocalized electron-driven reaction dynamics and the modulation of phase transitions to realize a high-performance NASICON cathode for sodium-ion batteries.
Wang et al. (Thu,) studied this question.