Gel interface for garnet-based lithium metal batteries with high loading cathode

Garnet-type electrolytes are ideal for lithium-metal batteries due to their high ionic conductivity and electrochemical stability. However, high interfacial resistance caused by poor contact with electrodes remains a challenge. To address this, we developed a flexible gel interlayer via in-situ polymerization to improve interface contact and reduce impedance. Additionally, a thick cathode with a laser-drilled channel structure was constructed to enhance gel electrolyte penetration and discharge capacity. Consequently, the Li/GEL-LLZTO-GEL/Li symmetric cell achieved a critical current density of 1.5 mA cm⁻² and a reduced interfacial resistance of 134 O at room temperature. The quasi-solid half-cell with the laser-drilled cathode maintained a discharge capacity of 132.4 mAh/g with an active material loading of 13.1 mg cm⁻² after 100 cycles. This work provides a simple and effective method for manufacturing safe and stable lithium metal batteries.