CaWO4 Nanoparticle-Assembled Hollow Spheres Anchored on Mesoporous Carbon Microbeads as an Anode Material for Lithium-Ion Batteries

Abstract The urgent need for high-performance lithium-ion batteries has driven significant interest in composite materials. However, the cooperative effects between metallic tungstate and carbon materials are not well understood. Herein, CaWO4 hollow microspheres/meso-carbon microbead (MCMB) composites are successfully synthesized via a highly efficient microwave irradiation strategy, resulting in high purity and uniform elemental distribution. In the composites, CaWO4 hollow microspheres, assembled with ultrafine CaWO4 nanoparticles with a mean diameter of 47−60 nm, evenly anchored on the MCMB outer surfaces. The electrochemical mechanism explored by in situ XRD analysis proves the transformation from CaWO4 to the reversible main phase of Li4WO5 with trace amounts of phases of Li2WO4 and Li2W2O7. The composites for Sample 4 exhibit a good thermal stability, and an increased peak current density, achieving capacities reaching 1356.7 mAh g−1 in the first cycle, 820.3 mAh g−1 in the second cycle, and 689.2 mAh g−1 in the 100th cycle. The analysis of the CaWO4/MCMB composite reveals an innovative energy storage process, offering valuable insights for the development of high-safety lithium-ion batteries.