High performance of HNaV 6 O 16 ·4H 2 O nanobelts for aqueous zinc‐ion batteries with in‐situ phase transformation by Zn(CF 3 SO 3 ) 2 electrolyte

Abstract Zn(CF 3 SO 3 ) 2 as an electrolyte has been widely used to improve the electrochemical performance for ZIBs due to that the bulky CF 3 SO 3 − can reduce the solvation effect of Zn 2+ and promote the ionic diffusion. Herein, we found that Zn(CF 3 SO 3 ) 2 electrolyte can induce different electrochemical mechanisms from ZnSO 4 electrolyte. Compared to the ZnSO 4 electrolyte, the HNaV 6 O 16 ·4H 2 O electrode with Zn(CF 3 SO 3 ) 2 electrolyte exhibits a high capacity of 444 mAh·g −1 at 500 mA·g −1 with a capacity retention of 92.3% after 80 cycles. Even, at a high rate of 5 A·g −1 , the HNaV 6 O 16 ·4H 2 O electrode delivers an initial discharge capacity of 328 mAh·g −1 with a capacity retention of 93.7% after 1000 cycles. Differing from the mechanism with ZnSO 4 electrolyte, the excellent cycle stability of HNaV 6 O 16 ·4H 2 O electrode can be attributed to the in‐situ phase transformation to Zn x V 2 O 5 · n H 2 O based on the co‐intercalation of Zn 2+ /H + .