Synergistic coupling of NiS1.03 nanoparticle with S-doped reduced graphene oxide for enhanced lithium and sodium storage

Abstract The interest on developing nickel sulfide based dual-role anode materials for both lithium-ion battery (LIBs) and sodium-ion battery (SIBs) has aroused broad attention. However, increasing their lithium and sodium storage performances necessitates smart structure design and fabrication. Herein, we demonstrate a facile strategy for the rational combination of NiS1.03 nanoparticles with sulfur doped reduced graphene oxide (NiS1.03/S-rGO), with the designed structure of ultrafine NiS1.03 nanoparticles uniformly anchored on or even wrapped in S-rGO. The systematic electrochemical studies demonstrate that the NiS1.03/S-rGO exhibits high reversible capacities of 996.1 mAh g−1 after 100 cycles at 0.1 A g−1 and 337.8 mAh g−1 up to 2000 cycles at 4 A g−1 as an anode material for LIBs. As for SIBs, the NiS1.03/S-rGO also displays high reversible capacities of 345.6 mAh g−1 at 0.1 A g−1 after 100 cycles and 242.1 mAh g−1 at 0.5 A g−1 after 200 cycles. Additionally, detailed structure analysis illustrates that the superior electrochemical performances mainly originate from the robust composite architecture where the NiS1.03 nanoparticles and S-rGO are tightly bridged via the doped sulfur atoms at the hetero-interface through a synergistic coupling effect, simultaneously guaranteeing the electrode integrity and fast diffusion kinetics. More importantly, the combination approach and mechanism understanding at the molecular level presented in this study show good promise on transition oxides/sulfides for high-performance alkali metal ion battery.