Excellent Electrochemical Performance of a Mesoporous Nickel Sulfide Anode for Na/K-Ion Batteries

Post-lithium-ion batteries (LIBs) have been widely studied owing to the extensive exploitation of lithium resources. Sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) are considered suitable alternatives to LIBs; however, the absence of an ideal anode material limits the practical applications of such post-LIBs. The present study demonstrates the application of mesoporous Ni3S2 as an anode material for SIBs and PIBs as well as the advantages of using a porous electrode in a high ionic-conductivity, low-viscosity, ether-based electrolyte. The utilization of mesoporous Ni3S2 as the anode material resulted in extraordinary rate and cycling performances. When SIBs were assembled using mesoporous Ni3S2 as the anode material, capacities of 610 and 154 mAh g–1 were obtained at current densities of 0.2 and 100 A g–1, respectively. Long-term cycling stability, with an initial capacity of 307 mAh g–1 and a capacity decay of 0.0085% per cycle, was also observed over 5000 cycles at 50 A g–1. Full cells assembled using Na3V2(PO4)3 and Ni3S2 as cathode and anode materials, respectively, delivered exceptional rate and cycling performances. Long-term cycling stability, with a capacity decay of 0.034% per cycle, was obtained over 1500 cycles at 10 A g–1. When PIBs were assembled using mesoporous Ni3S2 as the anode material, capacities of 534 and 38 mAh g–1 were obtained at 1 and 100 A g–1, respectively. Long-term cycling stability, with an initial capacity of 411 mAh g–1 and a capacity decay of 0.047% per cycle, was observed over 1000 cycles at 10 A g–1. Notably, the rate and cycling performances obtained in the present study are superior to those obtained in previous works on the use of Ni3S2 as the anode material for SIBs and PIBs.