Polyoxometalate@MOF derived porous carbon-supported MoO₂/MoS₂ octahedra boosting high-rate lithium storage

Structural stability and rapid charge-discharge capability of electrode materials are required for high performance lithium-ion batteries (LIBs). The materials derived from polyoxometalates (POMs) show special advantages in inhibiting capacity attenuation, and good dispersion or combination of POMs with metal-organic frameworks (MOFs) is an important method to obtain high activity anode composites for LIBs. In this study, a uniform MoO₂/MoS₂ heterostructure with surface supported carbon (C-MoO₂/MoS₂) was successfully fabricated from a [Cu₂(BTC)_4/3(H₂O)₂]₆[H₃PMo₁₂O₄₀] precursor, which showed not only the designed octahedral morphology but also fast charge transfer, long working life, and high rate performance. Superior reversible lithium storage capacity of 1047 mA h g^-1 after 300 cycles was obtained at 1 A g^-1. Even after 700 cycles at 5 A g^-1, the discharge specific capacity of 646 mA h g^-1 was maintained, and rate capability of 610 mA h g^-1 could be achieved at 10 A g^-1. The high capacitive contribution could be explained by the relatively large specific surface area of porous C-MoO₂/MoS₂, which was mainly caused by the supported carbon network and MoS₂ nanosheets, resulting in fast lithiation/delithiation processes.