| Sumario: | Silica (SiO2) 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 SiO2 unique lithiation mechanism, which involves its conversion to electroactive silicon (Si) and electrochemically inactive species. However, widespread adoption of SiO2 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 SiO2 conversion. Despite these efforts, the complex and multi-pathway nature of SiO2 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 SiO2 anodes, the lithiation process initiates at low potentials with the direct formation of Li4SiO4 and LixSi. Electrochemical activation potential was found to significantly influence the degree of conversion, with 10 mV identified as the optimal cut-off potential for maximizing SiO2 utilization. These findings provide key enablers to unlock the full potential of SiO2 anodes for battery technology.
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