Synthesis of 3D Ternary Microspheres Comprising MXene-CNT-MoSe2 Via a Facile Spray-Drying Process for High-Performance K-ion Battery Anode

This study presents a novel spray-drying method for fabricating three-dimensional (3D) porous composite microspheres (p-MX/CNT@MoSe2) as anodes for potassium-ion batteries (KIBs). These microspheres exhibited a well-defined porous structure formed by decomposition of latex beads and consisted of uniform MoSe2 sheets on a conductive MXene substrate and carbon nanotube (CNT) backbone. The precursor microspheres were synthesized from an aqueous solution containing MXene nanosheets, CNTs, latex beads, and molybdenum salts via spray-drying. The microspheres were homogeneously integrated into a 3D structure, establishing strong interactions. Single-step heat treatment under an inert atmosphere decomposed the latex beads, generating numerous pores, enhancing electrolyte permeation, and facilitating potassium-ion transport. The close MXeneCNT association enhanced the electronic conductivity and mitigated MoSe2 volume fluctuations during cycling. This architecture offers exceptional benefits, including efficient ion and electron transport, reduced potassium-ion diffusion distances, and excellent tolerance to volume changes. Electrochemical tests revealed the remarkable electrochemical performance of p-MX/CNT@MoSe2, with a specific capacity of 272 mA h g-1 at 0.5 A/g after 600 cycles and an outstanding rate capability, providing 225 mA h g-1 at a high 2.0 A/g current density. This study highlights the importance of rational design and synthesis for advancing next-generation electrode materials and sustainable energy storage solutions.