Silicon (Si) as an anode active material for lithium-ion batteries (LIBs) has considerably high theoretical specific capacity 3579 mAh/g. However, Si particles expand significantly during charging, making the electrode unsuitable and batteries difficult for long-term cycling1. In LIBs, capacity loss in the first and subsequent cycles is mainly attributed to the formation of a solid electrolyte interphase (SEI) layer, which consumes active lithium (Li)2. Among other proposed mitigating strategies, Pre-lithiation (preLi) presents to be one of the most viable approach. PreLi helps compensate for the Li loss, form an in-built SEI layer, improve rate capability via enhancing ion diffusivity and thus leading to higher coulombic efficiency (CE) and long-term cyclability3. In this study, ex-situ preLi will be applied on pure Si anode with a columnar structure to tune its material-level properties and thus improve its electrochemical performance.
Furthermore, the ageing behaviour of Si by scanning electron microscopy (SEM, Fig. 1) and improvement with preLi over 200 cycles in pouch cells (Fig. 2) were evaluated. Compared to other preLi techniques such as using Li metal or vapour deposition, our process can be applied to mass production in a continuous way
Summary of the presentation: Pure Si anodes were pre-lithiated with the lab- and the fab-scale process. Noticeable structural changes by pre-lithiation (preLi) were observed by SEM. PreLi reduced the initial capacity loss by 16% and improved cycle stability to 183% compared to without preLi. The experimental methods and cell types will be scaled up to larger formats. Optimum protocols such as constant current (CC) and pulse current (PC) were evaluated.