V2+-doped VS2 with rich defects for high-performance zinc storage in aqueous zinc-ion batteries

Layered VS2 material has been considered as a promising cathode for aqueous zinc-ion batteries. However, the insufficient active sites and sluggish ionic transfer kinetic stunt its development. Here, V2+-doped VS2 is developed as a cathode material for aqueous zinc-ion battery. These V2+-doped VS2 nanosheets are rich in defects in the interlayers and basal plane. The presence of defects brings about large number of active sites and diffusion paths for zinc ion storage and transfer. As a result, the V2+-doped VS2 cathode delivers a high reversible capacity of 156.3 mAh g−1 at 100 mA g−1, high-rate capacity of 123.4 mAh g−1 at 1000 mA g−1 and excellent cycle stability of 79.2% capacity retention at specific current of 1000 mA g−1 after 980 cycles. Moreover, ex-situ characterizations indicate that the V2+-doped VS2 undergoes a reversible Zn2+ and H+ (de)intercalation reaction during the discharge-charge process. This work will provide an ideal to cathode materials for aqueous zinc-ion batteries.