Improving the performance of lithium-ion batteries by micron-sized silicon particles coated with nano-ZnS anode materials

Abstract

Micron-sized Si-based materials have attracted extensive attention for lithium-ion batteries due to their high theoretical capacity and low cost. However, its large volume expansion and low conductivity limit its further development. Here, a Si/ZnS anode material is prepared, in which ZnS nanoparticles are uniformly attached to the surface of micro-Si particles. The conversion reaction of ZnS generates metal Zn and Li2S, and the alloying reaction of Zn generates LixZn, the metal Zn and LixZn are used as conductive additives to improve the conductivity of the composites, while Li2S is used as an artificial solid electrolyte interfacial phase to promote the stability of the solid electrolyte interface of the composites, so that the prepared micron-sized Si-based anode exhibits excellent cycling stability. At a current density of 0.5 A g−1, the initial coulombic efficiency reaches 78.67 % and the discharge specific capacity is 1540.2 mAh g−1 after 200 cycles.