Three-Dimensional Carbon Framework Anchored Polyoxometalate as a High-Performance Anode for Lithium-Ion Batteries

Recently, it has become very important to develop cost-effective anode materials for the large-scale use of lithium-ion batteries (LIBs). Polyoxometalates (POMs) have been considered as one of the most promising alternatives for LIB electrodes owing to their reversible multi-electron-transfer capacity. Herein, Keggin-type [PMo₁₂ O₄₀ ]^3- (donated as PMo₁₂ ) clusters are anchored onto a 3D microporous carbon framework derived from ZIF-8 through electrostatic interactions. The PMo₁₂ clusters can be immobilized steadily and uniformly on the carbon framework, which provides enhanced electrical conductivity and high stability. Compared with PMo₁₂ itself, the as-prepared novel 3D Carbon-PMo₁₂ composite displays a significantly improved Li-ion storage performance as an LIB anode, with excellent reversible specific capacity and rate capacity, as well as high cycling performance (discharge capacity of 985 mA h g^-1 after 200 cycles), which are superior to other POM-based anode materials reported so far. The high performance of the Carbon-PMo₁₂ composite can be attributed to the 3D conductive network with fast electron transport, high ratio of pseudocapacitive contribution, and evenly distributed PMo₁₂ clusters with reversible 24-electron transfer capacity. This work offers a facile way to explore novel LIB anodes consisting of electroactive molecule clusters.