Ultrafine MoO3 anchored in coal-based carbon nanofiber as anode for advanced lithium-ion batteries

Abstract Molybdenum trioxide (MoO3), which possesses unique layered nanostructure and high theoretical capacity, is currently under comprehensive research as one of the most promising lithium-ion anode materials. However, MoO3 suffers from sluggish electrode reaction kinetics and huge volume expansion, causing severe capacity fading during cycling processes. Herein, ultrafine MoO3 anchored in coal-based carbon fiber to form nanocomposites (MoO3/CCNFs) was prepared by electrospinning. The unique structure of the ultrafine MoO3 nanoparticles (1–3 nm) homogeneously embedded in coal-based carbon nanofibers showed advantages of short Li+ diffusion distance, fast reaction kinetics and reduced volume expansion. The specific surface area and pore volume of MoO3/CCNFs were increased induced by small molecular gas released during carbonization of the coal, which can supply more beneficial transport routes for electrolyte ions and relieve volume stress caused by Li+ insertion. Among all samples, 0.5-MoO3/CCNFs (the addition of coal was 0.5 g) exhibited excellent conductivity. As an anode for lithium storage, the 0.5-MoO3/CCNFs showed remarkable electrochemical properties with a high specific capacity of 801.1 mA h g−1 at 0.5 A g−1 after 200 cycles, as well as excellent rate capability. This work indicates that coal-based carbon nanofibers will allow further development in high performance MoO3 electrodes.