Tuning kinetics of SnS/Ni3S4 binary sulfides for high rate and long cyclic lithium-ion batteries

Nanomaterials synergy in a binary system offers a great opportunity for the development of high-performance electrode material for Lithium-ion batteries (LiBs). So far SnS/Ni3S4 binary sulfides are scarcely investigated as an anode for LIBs. In this work, to intrinsically enhance the kinetics of SnS, SnS/Ni3S4 (SN-x) binary sulfides were synthesized by introducing nickel sulfide with different stoichiometric ratios (0.5, 1, 2, and 3). The developed electrode (SN-2) delivers an initial discharge capacity of 2567 mA h g−1 and a high reversible capacity of 360 mA h g−1 at a current rate of 300 mA g−1 after 180 cycles with a Coulombic efficiency of over 97%. The electrochemical impedance spectroscopy (EIS) and density functional theory (DFT) confirm the improved kinetics of the SN-2 electrode as compared to other electrodes. The significantly enhanced performance of the SN-2 electrode can be attributed to the addition of an optimized amount of Ni3S4, synergistic effects between SnS and Ni3S4, generation of more active sites and structural integrity. This work suggests that the prepared SnS/Ni3S4 binary sulfides exhibit great promise for the development of efficient energy storage devices.