Controllably elevating the initial Coulombic efficiency of Li3VO4 anode via a facile electrode pre-lithiation technique for lithium-ion batteries
摘要
Li3VO4 has been a promising insertion anode material for Li-ion batteries, which has high theoretical capacity (up to ∼600 mAh g−1) and safe Li insertion voltage (0.5–1 V vs. Li/Li+). However, the low initial Coulombic efficiency (ICE) has always been the bottleneck limiting its commercialisation. Here, we propose a facile pre-lithiation method to controllably elevate the ICE by the post-treatment of the prepared Li3VO4 composite electrode based on an immersion reaction. In this process, the whole electrode was immersed in the liquid Li source, via which the ICE of the Li3VO4 electrode can be controllably elevated from 80% to over 100% within 5 min of pre-lithiation. Rather than the traditional powder treatment for pre-lithiation, this process we proposed minimizes the impact of pre-lithiation on the battery assembly process. Moreover, we further investigated the effect of this pre-lithiation process on the functional components in the electrode. For the first time the ICE of Li3VO4 electrode was elevated to 100%. As a result, the initial reversible capacity of LiFePO4∥Li3VO4 full cell was improved from 44.0 to 146.3 mAh g−1, demonstrating the feasibility and great potential of the process.