The Free-Standing Alloy Strategy to Improve the Electrochemical Performance of Potassium-Based Dual-Ion Batteries

Potassium-based dual-ion batteries (PDIBs) have shown good application prospects in large-scale energy storage systems. However, because of the limited theoretical capacity of carbonaceous anodes, the electrochemical performance of PDIBs reported at present is still unsatisfactory. Employing alloy materials as anodes should be a possible way to improve the capacity of PDIBs. Herein, free-standing porous carbon nanowires encapsulated with SnSb nanodots (SnSb@PCNWs) are first applied as the anodes for high-performance PDIBs. The free-standing structure design can reduce the cost and increase the proportion of active materials. Besides, the SnSb nanodots provide high potassium storage capacity, while the porous carbon nanowires can effectively buffer the volume expansion of SnSb nanodots. Consequently, the optimized PDIBs display high capacity of 255.3 mAh g–1 at 2 C (based on anodes), outstanding rate capability up to 12 C, and good cycling performance for 300 cycles at 10 C, which are the best results of the reported PDIBs.