Dislocation-engineered MoNb12-xVxO33 for ultra-fast and stable lithium storage at low temperature

Abstract

The advancement of lithium-ion batteries with high power density at low temperature is limited by sluggish Li⁺ diffusion kinetics and exacerbated polarization effects. Herein, MoNb_12-xV_xO₃₃ with abundant dislocations is constructed by a hetero-atom doping strategy, demonstrating enhanced fast rechargeability and low-temperature kinetics. The presence of dislocations in MoNb_12-xV_xO₃₃ lattice has been confirmed using transmission electron microscope, inverse fast Fourier transform and geometrical phase analysis. The dislocation-rich structure enables a reduction in Li⁺ desolvation barrier, lowers Li⁺ site energy and enhances Li⁺ diffusion capability, particularly at low temperature. The boosted ion diffusion and electronic transport have been established through multiple kinetic analyses and theoretical calculations. Furthermore, the introduced dislocations facilitate stress relief and maintain structural stability during rapid (de)lithiation procedures. Consequently, MoNb_12-xV_xO₃₃ displays a high reversible capacity of 116.8 mAh g⁻¹ at 100C. Particularly at −20 °C, MoNb_12-xV_xO₃₃ demonstrates exceptional long-term cycling stability exceeding 7000 cycles at 5C with 98.9 % capacity retention.