Unlocking the Electrochemical Activation of Diatomaceous Earth <scp>SiO<sub>2</sub></scp> Anodes for Next‐Generation Li‐Ion Batteries
Weicheng Hua, Per Erik Vullum, Kristianne Nilsen‐Nygaard Hjelseng, Johan Hamonnet, Pedro Alonso Sánchez, Jiefang Zhu, Zoltán Hegedues, Juan Rubio‐Zuazo, Federico Cova, Ann Mari Svensson, María Valeria Blanco
Abstract
Silica (SiO 2 ) anodes are promising candidates for enhancing the energy density of next‐generation Li‐ion batteries, offering a compelling combination of high storage capacity, stable cycling performance, low cost, and sustainability. This performance stems from SiO 2 unique lithiation mechanism, which involves its conversion to electroactive silicon (Si) and electrochemically inactive species. However, widespread adoption of SiO 2 anodes is hindered by their slow initial lithiation. To address this, research has focused on developing electrochemical “activation protocols” that involve prolonged low‐potential holding steps to promote SiO 2 conversion. Despite these efforts, the complex and multi‐pathway nature of SiO 2 lithiation process remains poorly understood, impeding the rational design of effective activation strategies. By introducing a multi‐probe characterization approach, this study reveals that, contrary to the previously proposed reaction mechanism of SiO 2 anodes, the lithiation process initiates at low potentials with the direct formation of Li 4 SiO 4 and Li x Si. Electrochemical activation potential was found to significantly influence the degree of conversion, with 10 mV identified as the optimal cut‐off potential for maximizing SiO 2 utilization. These findings provide key enablers to unlock the full potential of SiO 2 anodes for battery technology.