Phase-transfer-assisted confined growth of mesoporous MoS2@graphene van der Waals supraparticles for unprecedented ultrahigh-rate sodium storage

Abstract

Transition metal dichalcogenides (TMDs) are promising anode materials for sodium-ion batteries (SIBs), but suffer from low rate capability and poor cycling stability. Here, we describe our efforts in designing a unique MoS₂-based van der Waals (vdW) superstructure, namely mesoporous MoS₂@graphene supraparticles, for realizing unprecedented high-rate, long-life sodium storage. The key to obtaining mesoporous MoS₂@graphene vdW supraparticles is the high mass loading of the initially hydrophilic (NH₄)₂MoS₄ precursor into the hydrophobic mesoporous graphene, which is realized through a novel phase-transfer assisted method. Subsequent precursor decomposition confined in ∼11 nm mesopores triggers the epitaxial growth of MoS₂ nanosheets featuring a spherically curved geometry and an expanded interlayer spacing. Thanks to the greatly improved electron and ion transport properties enabled by the unique mesoporous vdW superstructure, the resulting MoS₂@graphene vdW supraparticles exhibit arguably the best rate performance ever reported.