Highly dispersed TaC nanowire cathodes via template-assisted electrolysis for enhanced lithium–oxygen batteries

Abstract

High efficiency oxygen electrode is essential to achieve long cycle life of lithium–oxygen battery. In this study, we present a novel approach involving the fabrication of porous, interwoven tantalum carbide (TaC) nanowires via molten salt electrolysis, with multi-walled carbon nanotubes (MWCNTs) serving both as a carbon source and as a structural template. In contrast, using carbon nanoparticles as carbon source results in severe agglomeration of TaC particles. These TaC nanowires offer sufficient storage space for discharge products, establish efficient ions and O2 diffusion pathways, and expose numerous catalytic active sites to effectively mitigating the formation of carbonate byproducts. The lithium–oxygen battery with TaC nanowires oxygen electrode demonstrates a high specific discharge capacity of 11,856.69 mAh g−1, a stable cycle life of 120 cycles at 500 mA g−1 with the limited capacity of 1000 mAh g−1, and a discharge/charge overvoltage gap of 1.13 V. This study introduces a promising approach for the development of new catalysts based on transition metal carbides for lithium–oxygen batteries.