Advanced Multifunctional Sodium‐Ion Battery with High Current Conversion, Long Cycle Life, and All‐Climate Temperature Range by Dual‐Multivalent Cation Doping Strategy

Abstract The polyanionic fluorophosphate Na 3 V 2 (PO 4 ) 2 O 2 F is regarded as one of the most prospective cathode materials for high‐energy‐density sodium‐ion batteries (SIBs), owing to its high operating voltage and ideal theoretical specific capacity. Nevertheless, its low kinetics significantly restrict its electrochemical performance and practical applications. In this paper, a novel bimetallic‐doped cathode material, Na 3 V 1.90 Ti 0.05 Cr 0.05 (PO 4 ) 2 O 2 F (NVTC), based on V‐site multivalent cations, is developed. When used as a cathode material in sodium‐ion half batteries, it can be stably cycled for 3000 cycles with a capacity maintenance ratio of 96.88% at an ultra‐high current density of 20 C. Furthermore, replacing the ether electrolyte allows NVTC to cycle stably for 150 cycles with an average Coulombic efficiency of 98.34% under harsh conditions of −15 °C (1 C current density). Moreover, NVTC exhibits a preliminary specific capacity of 110.5 mAh g −1 at 50 °C and can operate stably for 2500 cycles (5 C current density). Remarkably, NVTC demonstrates ultra‐fast charging capability (full charge in just 1.21 min at 30 C current density) and a low self‐discharge rate (0.006318 V h −1 ), alongside considerable electrochemical performance for high‐quality loads. This study is expected to positively impact the future development of advanced multifunctional SIBs.