Tuning the pH value of electrospinning precursor to synthesize Fe2O3/MoO2/Fe2(MoO4)3 as anode for lithium-ion batteries to boost the reaction kinetics and energy/power density performance

Abstract

In this work, a simple strategy for the synthesis of Fe2O3/MoO2/Fe2(MoO4)3 anode material was proposed, which controls the surface tension and viscosity of electrospinning precursor by adjusting its pH value, and optimizes the structure and morphology of the product. Compared with the Fe2(MoO4)3, the Fe2O3/MoO2/Fe2(MoO4)3 heterostructure not only effectively reduces the deactivation of the electrode material, but also increases the insertion sites of lithium-ions. Meanwhile, the built-in electric field generated near the heterointerface increases the diffusion coefficient of lithium-ions and improves the interfacial reaction kinetics. The sample obtained at a pH value of 1.85 exhibits the best electrochemical performance. The battery maintained a high reversible capacity (1014.2 mAh·g−1) after 480 cycles at 1000 mA·g−1, with an average specific capacity decrease rate of only 0.035 % per cycle. The mechanism of improving reaction kinetics and lithium storage performance by heterostructures has been proposed. Based on the interfaces confined effect of heterostructures and the formation of built-in electric fields, this work provides a strategy to adjust the spinning behavior by changing the pH value of precursors to achieve product structure optimization and electrochemical performance improvement, which will provide strong support for the research of high power/energy densities LIBs.