High-Performance Lithiated SiO<i>_x</i> Anode Obtained by a Controllable and Efficient Prelithiation Strategy

Abstract

Silicon-based electrodes are promising and appealing for futuristic Li-ion batteries because of their high theoretical specific capacity. However, massive volume change of silicon upon lithiation and delithiation, accompanied by continual formation and destruction of the solid-electrolyte interface (SEI), leads to low Coulombic efficiency. Prelithiation of Si-based anode is regarded as an effective way for compensating for the loss of Li⁺ in the first discharging process. Here, a high-performance lithiated SiO<i>_x</i> anode was prepared by using a controllable, efficient, and novel prelithiation strategy. The lithiation of SiO<i>_x</i> is homogeneous and efficient in bulk due to well-improved Li⁺ diffusion in SiO<i>_x</i>. Moreover, the in situ formed SEI during the process of prelithiation reduces the irreversible capacity loss in the first cycle and thus improves the initial Coulombic efficiency (ICE). Half-cells and full cells based on the as-prepared lithiated SiO<i>_x</i> anode prominently increase the ICE from 79 to 89% and 68 to 87%, respectively. It is worth mentioning that the homogeneously lithiated SiO<i>_x</i> anode achieves stable 200 cycles in NCM622//SiO<i>_x</i> coin full cells. These exciting results provide applicable prospects of lithiated SiO<i>_x</i> anode in the next-generation high-energy-density Li-ion batteries.