Zn-doped V2O5 cathode material for lithium-ion batteries operating in the voltage window of 1.5–4.0 V

Abstract

In this work, Zn-doped vanadium pentoxide (V₂O₅) cathode materials for lithium-ion batteries (LIBs) were prepared via a facile wet chemical solution process followed by post-calcination treatment. The zinc doping impact on the phase structure, surface morphology, chemical states, and specific surface area of the as-prepared powders was studied using X-ray diffraction (XRD), emission scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS), and Brunauer–Emmet–Teller (BET). The electrochemical behavior of undoped (VZ0%) and Zn-doped V₂O₅ with 1 wt% (VZ1%) as cathodes for LIBs was investigated by cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS) measurements. As a result, the VZ1% sample possesses better properties than the VZ0% and suitable for use as cathode material in LIBs. The VZ1% sample displayed a higher specific discharge capacity (210 mAh g⁻¹ at 0.25 C), excellent cycle stability with a specific capacitance retention of 63% after 50 cycles of the charge/discharge process, and low charge transfer reaction resistance (R_ct = 107 Ω). The considerably improved electrochemical performance of Zn-doped V₂O₅ can be attributed to its porous structure, lowest crystallite size, cell volume expansion, highest specific surface area, enhanced electronic conductivity and lowest charge transfer resistance.