Flexible N doped carbon/bubble-like MoS₂ core/sheath framework: Buffering volume expansion for potassium ion...

Suitable anode materials for potassium ion batteries (KIBs) with high capacity, good reversibility and stable cycling performances are still in large demand. Here, flexible N doped carbon/bubble-like MoS₂ core/sheath framework (MoS₂/NCS) is prepared as an anode material for potassium ion batteries. The N doped carbon sponge (NCS) skeleton with good conductivity and high surface area guarantees superior rate capability and high stability of MoS₂/NCS anode. The chemical bonds (CMo) firmly bridge MoS₂ and NCS together, which further ensures MoS₂/NCS stable cycling performance. More importantly, volume expansion is greatly buffered during cycling by this unique structure: the voids between bubble-like MoS₂ sheath and NCS core can effectively buffer volume expansion generated during potassium intercalation/deintercalation; the enlarged interlayer spacing contribute more space to buffer volume change; the ultrathin nanosheets can shorten the charge diffusion distance and buffer volume change. As a consequence, MoS₂/NCS delivers a capacity of 374 mAh g^-1 over 200 cycles at 50 mA g^-1. Even at 1000 mA g^-1, a capacity of 212 mAh g^-1 can still be obtained over 1000 cycles. We believe this MoS₂/NCS structure will highlight the potential of MoS₂ in practical KIBs applications.