Nickel-doped Nb18W16O93 nanowires with improved electrochemical properties for lithium-ion battery anodes

Abstract

Recently, niobium tungsten oxide nanowires have been reported to be a promising anode material for lithium-ion batteries (LiBs). This material has demonstrated high theoretical capacity, significant structural stability, high power density, and environmental friendliness. Nonetheless, its low electronic conductivity is a significant drawback that needs to be addressed. More so, it is desirable to enhance its electrochemical performance to meet the needs of current energy applications. In this study, pristine and nickel-doped (Ni = 1 wt%, 3 wt%, 5 wt%) niobium tungsten oxide nanowires were fabricated using the electrospinning technique, followed by annealing. The effect of nickel doping content on the morphology, structure, and electrochemical performance of niobium tungsten oxide nanowires was investigated. The XRD results show that the Ni doping expanded the unit cell and enhanced the lithium-ion diffusion in the Nb18W16O93 nanowires. The electrochemical test results indicate that the 3 wt% nickel-doped condition exhibits remarkable capacity retention of 93.1% over 500 cycles at a high current rate of 5 C. Furthermore, the Ni doping significantly enhanced the electronic conductivity compared to the pristine Nb18W16O93 nanowires. The results obtained from the CV test also show that Ni doping lowered the polarization and increased the lithium-ion diffusion coefficient.