Catalytic anode surface enabling in situ polymerization of gel polymer electrolyte for stable Li metal batteries

Employing quasi-solid-state gel polymer electrolyte (GPE) instead of the liquid counterpart has been regarded as a promising strategy for improving the electrochemical performance of Li metal batteries. However, the poor and uneven interfacial contact between Li metal anode and GPE could cause large interfacial resistance and electrochemical Li stripping/plating inhomogeneity, deteriorating the electrochemical performance. Herein, we proposed that the functional component of composite anode could work as the catalyst to promote the in situ polymerization reaction, and we experimentally realized the integration of polymerized-dioxolane electrolyte and Li/Li₂₂Sn₅/LiF composite electrode with low interfacial resistance and good stability by in situ catalyzation polymerization. Thus, the reaction kinetics and stability of metallic Li anode were significantly enhanced. As a demonstration, symmetric cell using such a GPE-Li/Li₂₂Sn₅/LiF integration achieved stable cycling beyond 250 cycles with small potential hysteresis of 25 mV at 1 mA·cm⁻² and 1 mAh·cm⁻², far outperforming the counterpart regular GPE on pure Li. Paired with LiNi_0.5Co_0.3Mn_0.2O₂, the full cell with the GPE-Li/Li₂₂Sn₅/LiF integration maintained 85.7% of the original capacity after 100 cycles at 0.5 C (1 C = 200 mA·g⁻¹). Our research provides a promising strategy for reducing the resistance between GPE and Li metal anode, and realizes Li metal batteries with enhance electrochemical performance.