Glucose-assisted core-shell C-MoO2@C-MoS2 microspheres for boosting lithium-ion diffusion kinetics

Abstract

Abstract

Molybdenum-based materials, such as MoO2 and MoS2, have gathered significant attention in lithium-ion battery research because of their high theoretical specific capacity. However, their practical use is constrained by inherent low conductivity and structural degradation that occurs in the lithiation/delithiation processes. Herein, uniform core-shell C-MoO2@C-MoS2 microspheres with a diameter of ca. 1.2 μm were successfully fabricated through synchronous reduction and sulfidation of MoO3, using an economical glucose as carbon resource, co-reductant, and structure directing agents. In-situ XRD analysis reveals the excellent reversibility and structural stability of C-MoO2@C-MoS2 during the charge-discharge cycle. Moreover, the unique core-shell structure also endows C-MoO2@C-MoS2 with a high reversible lithium storage capacity (377 mAh·g−1 after 550 cycles at 0.1 A g−1, coulombic efficiency >99.5 %), low charge-transfer resistance (52.4 Ω), and a high Li+ diffusion kinetics (DLi+ = 3.89 × 10−11 cm2 s−1). Notably, C-MoO2@C-MoS2 contributes significantly to the interlayer capacitance, accounting for 69 % at 1.0 mV s−1. This study offers a novel and straightforward approach for constructing core-shell structured composites with potential applications in new energy technologies.