New insight of in-situ generation of composite cathode by converting Na3V2(PO4)3@C to improve aqueous zinc-ion batteries' performance.

• The Na 3 V 2 (PO 4) 3 @C undergoes a phase conversion (V 2 O 5 , NaV 3 (PO 4) 3 , Zn 3 V 4 (PO 4) 3) after 50 cycles. • The same phase conversion products are achieved after the batteries were treated for 1 cycle at 60 °C. • This is the first reported use of in-situ generation of composite as a cathode material. The NASICON-structure Na 3 V 2 (PO 4) 3 is attracted lots of attention due to its three-dimensional ion diffusion channels, high discharging platform and small volume deformation, which has become the most potential cathode material candidates for aqueous zinc-ion batteries. Nevertheless, we found that NVP@C undergoes a structural phase change which is converted to composite (V 2 O 5 , NaV 3 (PO 4) 3 , Zn 3 V 4 (PO 4) 6) after 50 cycles in this study. Here, we exploited the in-situ generation of composite by cycling the NVP@C batteries at 60 °C for only 1 cycle (NVP@C-60 °C) to promote the performance of cathode material for aqueous zinc-ion batteries. The NVP@C-60 ℃ display a high capacity of 164 mA h g−1 at 100 mA g−1 and excellent rate performance (155 mA h g−1 at 1000 mA g−1) are realized. This is the first reported in-situ generation of composite as a cathode material for aqueous zinc-ion batteries so far. This work breaks the original conventional thinking to present new insight to developing cathode materials for zinc energy storage. [ABSTRACT FROM AUTHOR]