Interlayer-expanded MoS2 vertically anchored on graphene via COS bonds for superior sodium-ion batteries

Highlights: • A well-designed structure with interlayer-expanded MoS₂ vertically anchored on graphene substrates (v-MoS₂/rGO) is achieved. • C-O-S bonds provide a favorable electron transfer path in graphene-MoS₂ interface. • The assembled Na⁺ battery shows high rate performance and long cycling stability. -- Abstract: Rational materials design is critical to develop advanced electrodes for high-performance sodium-ion battery. In this work, a well-designed structure with interlayer-expanded molybdenum disulfide (MoS₂) vertically anchored on graphene substrates (v-MoS₂/rGO) is achieved by one-pot hydrothermal synthesis. The vertical anchored MoS₂ and high conductivity graphene sheets provide a good path for electrons/ion transfer. More importantly, the direct linkage of O from functional group on graphene oxide (GO) with edge S of MoS₂ (C-O-S) is constructed, which can maintain the stability of the v-MoS₂/rGO electrode and enhance its electrons transport rate for the high-rate performance and long cycle life. The assembled sodium-ion battery shows high rate performance (129.2 mAh g⁻¹ at 10 Ag⁻¹) and long cycling stability (251.2 mAh g^‐1−1 at 2 Ag⁻¹ after 1000 cycles with an ultra-low degradation of 10.9 μAh g⁻¹ per cycle). The excellent performance makes the designed structure a fascinating anode for sodium battery.