Phosphorus-doped copper sulfide microspheres with a hollow structure for high-performance sodium-ion batteries

Abstract

Transition metal compounds based on the conversion reaction mechanism are expected to replace traditional insertion materials because of their large theoretical specific capacity, high gravimetric energy density and richer redox reaction sites. Copper sulfide based on the conversion reaction mechanism is considered a promising anode material for sodium-ion batteries due to its abundant resources, low cost, and high theoretical specific capacity (560 mA h g⁻¹). In this work, P-doped CuS micromaterials (P-CuS) with a hollow spherical morphology were successfully synthesized through a simple hydrothermal reaction. The P-CuS as an electrode material possesses a high reversible capacity that reached 525.8 mA h g⁻¹ after 100 cycles at a current density of 0.2 A g⁻¹. The P-CuS hollow microspheres maintained a capacity of 442.1 mA h g⁻¹ after 2000 cycles at a high current density of 10 A g⁻¹, which is almost 100% coulomb efficiency, indicating good long-term cycling stability at high current density. Meanwhile, the electrode of P-CuS hollow microspheres exhibited exceptional rate performance and dynamic stability. The excellent electrochemical performance of P-CuS can be attributed to the unique structure of hollow microspheres, the doping of P atoms, and the subsequent surface pseudocapacitive behavior. Therefore, the construction of a hollow structure and the doping of P atoms are assumed to be a promising strategy to improve the electrochemical performance for sodium-ion batteries.