Drastically-enlarged interlayer-spacing MoS2 nanocages by inserted carbon motifs as high performance cathodes for aqueous zinc-ion batteries

Abstract

Two dimensional (2D) layered nanomaterials have emerged as a promising energy storage material due to inherent 2D channels. Nevertheless, low capacity and poor cycling stability limit their practical applications in aqueous zinc ion batteries (AZIBs). The article innovatively introduces N-doped carbon motifs between the layers of MoS2 to produce the interlayer spacing enlarged MoS2 nanocages with multistage structures, via a strategy combining interlayer polymerization with template assistance. NC motifs provided abundant channels for substance transport and electron transfer. Cage-shaped structure inhibits stacking of nanosheets during synthesis and application, and alleviates volume changes caused by ion migration during (dis)charging. Therefore, this novel MoS2 exhibit excellent high rate performance (247.8 mA h g−1 at 0.1 A g−1 and 100.9 mA h g−1 at 8.0 A g−1) and excellent cycling stability (85.6 % capacity retention after 3200 cycles at 1.0 A g−1) when applied as cathodes for AZIBs. The flexible quasi-solid batteries based on C-MoS2-NC cathode exhibit excellent electrochemical performance under different bending conditions. The energy storage mechanism regarding highly reversible of zinc ion (de)insertion is elucidated through in-situ XRD and ex-situ Raman technology. The calculation of density functional theory further reveals the reduction of the ion diffusion barrier accelerates the electrochemical kinetics.