Electron transition enhanced in-situ co-reduction mechanism enabling high-capacity and stable lithium storage for MoO3-x anode

Abstract

Transition metal oxides (TMOs) often achieve excellent performance through micro-scale regulation and structural evolution, especially as electrode materials for lithium-ion batteries (LIBs). Recently, in order to improve the inferior rate capability, sluggish reaction kinetics, and fast capacity decay of transition metal oxide MoO3 during a long-term charge/discharge process, a variety of composite materials and synthetic routes have been developed. However, the expensive multi-step synthesis, weak interaction between composites, and poor intrinsic conductivity of MoO3 severely hinder the large-scale commercial application of composites. Therefore, a simple, green and low-cost electron transition enhanced one-step co-reduction strategy is proposed to synthesize a novel MoO3-x nanoparticle/few-layer reduced graphene oxide (rGO) composite (denoted as MNR) with strong terminal-bonding (MoO2–O–C-rGO). The strategy ingeniously realizes the fabrication of oxygen vacancies (MoO3-x) and the in-situ reduction of graphene oxide (GO), as well as accomplish the dual regulation of scale and structure by forming a strong terminal-bonding effect. Significantly, the obtained MNR anode exhibits an ultrahigh discharge capacity (1415 mA h g−1 at 1.0 A g−1) and long cycle stability (94 % capacity retention after 700 cycles), which is superior to the previously reported MoO3-based composites. Moreover, the full battery coupled with LiFePO4 cathode also reveals a competitive energy density (369 Wh kg−1). The results suggest a novel approach for the fabrication and wide application of TMOs/rGO composites.