Solid-state lithium (Li) metal batteries with enhanced safety and high energy density have attracted ever-increasing attention. However, it is challenging to construct an effective ionic conduction pathway in the composite cathode of the solid-state batteries, especially when the mass loading of active materials is high. Herein, we prepare a gel composite cathode by introducing an in-situ polymerized gel polymer electrolyte into the cathode. The voids in the cathode and the gaps between the cathode and the electrolyte layer are filled with the gel electrolyte, and thus a fast Li-ion conduction pathway is established. Solid-state Li metal batteries with LiCoO₂ and LiFePO₄-based gel composite cathodes show excellent cycling performance. Even at a high mass loading of 11.09 mg cm⁻², the cell with a LiCoO₂–based gel composite cathode has a long cycle life at 0.088 mA cm⁻² at room temperature. The experimental data demonstrate that the conductive gel composite cathode has promising applications in solid-state batteries with high energy density.

具有增强的安全性和高能量密度的固态锂（Li）金属电池吸引了越来越多的关注。然而，在固态电池的复合阴极中构造有效的离子传导路径是有挑战性的，尤其是在活性材料的质量负载较高时。在此，我们通过将原位聚合的凝胶聚合物电解质引入到阴极中来制备凝胶复合阴极。阴极中的空隙以及阴极与电解质层之间的间隙被凝胶电解质填充，因此建立了快速的锂离子传导路径。具有LiCoO ₂和LiFePO _4的固态锂金属电池基的凝胶复合阴极显示出优异的循环性能。即使在11.09 mg cm ^{- 2的}高质量负载下，具有基于LiCoO ₂的凝胶复合阴极的电池在室温下仍具有0.088 mA cm ^{- 2}的长循环寿命。实验数据表明，导电凝胶复合阴极在高能量密度的固态电池中具有广阔的应用前景。