Nano-Molybdenum Oxide Modified Expanded Graphite for High performance Lithium-ion Batteries

Abstract

Graphite anodes for lithium-ion batteries still faces practical challenges, including the limitation of theoretical specific capacity and sluggish lithium-ion storage kinetics, which correspond to low-energy-density and unsatisfactory fast-charging performance. Nano-molybdenum oxide (nano-MoO3), exhibiting high theoretical specific capacity, work function and excellent stability, represents a promising modification agent for graphite anode to enhanced electrochemical performance. Herein, this study developed the nano-MoO3 decorated within the bulk and surfaces of expanded graphite anode material (nMO-EG). The reversible conversion reactions between nano-MoO3 and lithium enhances the specific capacity of nMO-EG, achieving a high capacity of 701.9 mAh g−1. A stable solid electrolyte interphase film, enriched with inorganic Li2O and LiF, was formed on the surface of the nMO-EG anode, attributing to a reversible capacity of 613.8 mAh g−1 and superior cycling stability over 600 cycles. The expanded layer of nMO-EG anode exhibits a low lithium-ion diffusion energy barrier of 0.15 eV, which enhances its fast-charging capability that delivers a reversible specific capacity of 236.3 mAh g−1 at 5 A g−1. This study provides new insights into the stability of the graphite modification and provides a promising alternative for high-energy-density and fast-charging graphite anode materials in lithium-ion batteries.