Polyvinylpyrrolidone-Coated CuS as Efficient Anodes for Aqueous Zinc-Ion Batteries with High Capacity and Long Life

In this work, CuS@PVP nanospheres with large specific surface areas were successfully prepared via a one-step hydrothermal process by introducing the polyvinylpyrrolidone (PVP) surfactant into the precursor and modulating its dosage. As an anode material for aqueous zinc-ion batteries, the prepared CuS@PVP can shorten the transmission distance of Zn2+ and electrons and increase the number of reaction sites. CuS@PVP with 0.2 g of PVP added has a specific capacity of 305.4 mAh g–1 at a current density of 0.2 A g–1 and an ultralong cycle life of 2000 cycles at a current density of 2 A g–1. In addition, the capacity of the CuS@PVP||Na–MnO2 full cell is as high as 220.0 mAh g–1 at a current density of 0.2 A g–1, and the capacity retention rate is 85.9% after 100 cycles. The results prove that CuS@PVP is an excellent choice as an anode material for aqueous zinc-ion batteries.