A High-Crystalline NaV_(1.25)Ti_(0.75)O_4 Anode for Wide-Temperature Sodium-Ion Battery

摘要

Sodium-ion batteries with abundant and low-cost sodium resources is a promising alternative to Li-ion batteries in large-scale energy applications. While the anode materials, due to their insufficient cycling life and insecure voltage, could not still satisfy the market demands, especially in the wide-temperature fields, here, a high-crystallinity anode material with post-spinel structure, namely NaV1.25Ti0.75O4, which always maintains excellent electrochemical performance at the widely variable temperatures, is reported. The results indicate that this anode delivers a high-safety and ultrastable room-temperature performance (i.e., an average output voltage of 0.7 V vs Na+/Na and the ultralong cycling life over 10 000 cycles) and good wide-temperature performance (below 9% capacity variation at 60 and -20 degrees C compared to that at 25 degrees C). These excellent achievements could benefit from the long durability and stability of 1D channels and superfast ion diffusion in a temperature-dependent range. This finding provides a promising strategy to construct the safe and stable full-cell prototypes and promotes the wide-temperature application of sodium-ion batteries.