NiS2 wrapped into graphene with strong Ni-O interaction for advanced sodium and potassium ion batteries

Abstract Sodium/potassium ion batteries (SIBs and PIBs) have attracted extensive attention because of the low cost and comparable energy density with lithium-ion batteries. However, their application is still impeded by the inherent sluggish kinetics of suitable anode materials. Herein, graphene-supported NiS2 nanocrystals with a strong chemical Ni-O interaction (denoted as c-NiS2/rGO) are fabricated and adopted as a universal anode material for both SIBs and PIBs. It is found that the Ni-O interaction can chemically bridge NiS2 with graphene networks, favoring the thermo-dynamical stabilization of NiS2/rGO heterostructure and dynamically accelerated ion/electron transport as revealed by a Density Functional Theory (DFT) simulation. Electrochemical investigations on SIB and PIB reveal a high cycle stability. Specifically, the c-NiS2/rGO shows a reversible capacity of 580.6 mAh g−1 at 5 A g−1 and 215.8 mAh g−1 at 2 A g−1 in SIB and PIB, respectively. This work shed lights on manipulation of nickel-sulfide/rGO based materials through interfacial engineering for high-performance energy storage devices.