Enhancing the performance of lithium-ion batteries with NiCo2S4/C-hollow sphere nanocomposites

Abstract

Binary metal sulfides, particularly NiCo₂S₄, exhibit significant promise as anode materials for lithium-ion batteries due to their exceptional electrical conductivity and superior capacity compared to mono-metal sulfides and oxides. Herein, NiCo₂S₄/Carbon hollow spheres nanocomposites were successfully synthesized via high-temperature carbonization and hydrothermal methods as an anode material for lithium-ion batteries. The designed structure takes full advantage of the high specific capacity of NiCo₂S₄ and the high conductivity of carbonaceous material. The uniform distribution of NiCo₂S₄ nanoparticles on the surface of carbon hollow spheres can increase the number of active sites for electrochemical reactions, and the large inner cavity of carbon hollow spheres efficiently prevents volume change during cycling. Under the synergistic effect between NiCo₂S₄ and carbon hollow spheres, experimental results demonstrate that the electrode exhibits a high specific capacity of 777.5 mAh g⁻¹ at a current density of 0.2 A g⁻¹. After 500 cycles, the capacity is maintained at 343.6 mAh g⁻¹. Furthermore, electrochemical kinetic analysis reveals that the contribution of capacitance increases to 80% at a scan rate of 1.6 mV s⁻¹. The excellent electrochemical performance can be attributed to the unique hollow nanostructure, which facilitates rapid electron transport and ion diffusion, improves contact areas between the electrolyte and active materials, enables efficient electrolyte diffusion, and prevents volume changes during the charging/discharging process. This study provides new insights and methods for developing future advanced anode materials for lithium-ion batteries.