Exploring lithium ion storage ability and cycling performance of the Cu₂SnSe₄ nanoparticles encapsulated with nitrogen-doped carbon

Lithium-ion battery (LIB) is an essential energy storage device in numerous applications such as electronic devices and electric vehicles. Nevertheless, LIBs cannot meet some requirements, such as high energy and power density. To achieve these goals, the development of an electrode material with high capacity and fast kinetics is needed. Here, we report on Cu₂SnSe₄ nanoparticles embedded with N-doped carbon (Cu₂SnSe₄@N-C) as a new anode material. The cycling tests revealed that the Cu₂SnSe₄@N-C delivered a higher discharge capacity of 788.6 mAh g⁻¹ than the pristine Cu₂SnSe₄ (14.8 mAh g⁻¹) after 100 cycles at 100 mA g⁻¹. It also exhibited a better long term cycling stability (365 mAh g⁻¹ after 200 cycles at 2000 mA g⁻¹) and excellent rate performance at a high current density. Such a superior performance is associated with the surface coating of N-doped carbon on the Cu₂SnSe₄ nanoparticles. It can accommodate the volume strain during charge-discharge cycles and enhance ionic and electronic transport within the electrode material. The N-doped carbon can also act as a fence that strongly suppresses the dissolution of polyselenide into the electrolyte solution through strong chemical adsorption.