Rational Design of Carbon Covered V2O3-x Decorated Amorphous MoO2 Double-Core–Shell Structure Facilitates Ultra-High Stability and High-Rate Performance in Lithium-ion Batteries

Abstract

Amorphous materials, which bear unique atomic arrangements, have garnered significant study on lithium-ion batteries due to inherent properties, including isotropy and defect distribution. Herein, a novel amorphous MoO_2-x@V₂O_3-x@C double-core–shell structure is ingeniously designed by simple solvothermal and pyrolytic reactions, and the valence states of amorphous MoO₂ and V₂O₃ are precisely characterized using X-ray absorption near-edge structure spectroscopic measurements. In situ XRD, in situ EIS and density functional theory calculations confirm that the amorphous structure enhances the electronic conductivity of MoO_2-x@V₂O_3-x@C-2, optimizes the Li⁺ relocation paths and the associated energy barriers, thus improving the Li⁺ diffusion kinetics. Furthermore, the formation of V₂O_3-x layer, along with the establishment of a 3D network structure of amorphous carbon, enhanced the electronic conductivity and mitigated swelling of the electrodes, thereby improving stability during battery cycling. Benefiting from this multiscale coordinated design, the optimized MoO_2-x@V₂O_3-x@C electrodes exhibit high discharge capacity of 477.5 mAh g⁻¹ at 10.0 A g⁻¹, along with exceptional cycling stability, showing minimal capacity loss even after undergoing 1000 cycles at 20.0 A g⁻¹. Additionally, MoO_2-x@V₂O_3-x@C||LiCoO₂ full batteries maintain good capacity over 300 cycles. The proposed amorphous and core–shell structure fabrication concept offers novel insights into developing advanced high-efficiency energy storage materials.