Cobalt-doped Vanadium Pentoxide Microflowers as Superior Cathode for Lithium-Ion Battery

Abstract

To meet the ever-increasing demand for higher energy density and power density, developing cathode materials with high specific capacity has become an urgent problem. V₂O₅ has been considered as one of the most promising cathodes for its high theoretical specific capacity (443 mAh g⁻¹), abundant source, and low cost. In this work, cobalt-doped vanadium pentoxide (Co-V₂O₅) microflowers were synthesized through a simple solvothermal method. The doped Co not only improves the electronic conductivity but also increases the diffusion coefficient of the lithium ions. Benefiting from the appropriate amount of Co doping, the charge transfer impedance decreases from 51 to 28 Ω and the diffusion coefficient of the lithium ions increased from 2.81×10⁻¹⁷ cm² s⁻¹ to 3.31×10⁻¹⁶ cm² s⁻¹. The optimal Co-V₂O₅ microflowers deliver a high reversible capacity of 166 mAh g⁻¹ after 200 cycles.