Construction of lotus stem-like Li3VO4 wrapped on carbon fibers via chemical lithiation promoting interfacial dynamics for capacitive lithium storage

Abstract

Oxides based on vanadium redox couple, such as orthorhombic Li3VO4, has drawn great attentions due to its high theoretical capacity and moderate operating voltage. However, the rate property is largely hindered by the slow interfacial dynamics of Li3VO4. Here we synthesized the lotus stem-like Li3VO4 wrapped in N-doped carbon fibers (Li3VO4/C NF) stemmed from the chemical lithiation of V2O3/C NF. The knobbly Li3VO4 rooted in the interconnected carbon fibers provides abundant active sites and well-developed conductive networks. Thus, this anode delivers high specific capacity of 558.9 mAh g−1 at 0.2 A g−1 and excellent rate capacity of 419 mAh g−1 at 2 A g−1 sustaining 900 cycles with an average potential of 0.7 V vs. Li+/Li. Furthermore, the kinetic analysis reveals that the pseudocapacitance dominants the lithium storage process and the favorable interfacial ion and electronic transport is responsible for the enhanced rate performance. The full cell (Li3VO4/C NF||LiFePO4) also shows a competitive performance for commercialization. This work boosts the development of vanadium-based anode materials with desired electrochemical properties meeting devices requirements.