Key to intimately coupling metal chalcogenides with a carbon nanonetwork for potassium-ion storage

Intimately coupling metal chalcogenides (MCs) with carbon materials is critical for boosting their application performances. However, since MCs and carbon materials are usually two types of incompatible materials, a non-uniform carbon/MC interface is easily formed, especially for multidimensional nanostructures. Herein, we propose an interfacial engineering strategy to enhance the interaction between a three-dimensional nanonetwork-structured carbon aerogel (CA) and MCs. The key to this strategy is the introduction of substantial oxygen-containing functional groups into the CA, which greatly improves its compatibility with MC precursors, and thus enables MCs to grow on the CA framework homogeneously. The optimized CA/MC interface enables extremely compact bonding interaction between the CA and MC nanosheets. Benefitting from a well-organized structure, the synthesized CA@MC composites show remarkable potassium-ion storage performances and electrochemical kinetic properties. As a demonstration, the CA@MoS2 composites show high reversible capacity (389 mA h g−1 at 100 mA g−1), excellent rate performance (capacity retention exceeds 40% with a 5-fold increase of the current density) and an enhanced ion diffusion rate when used as an anode material for potassium-ion batteries.