In-situ generated Li2S-based composite cathodes with high mass and capacity loading for all-solid-state Li-S batteries

The all-solid-state Li-S batteries assembled by inorganic solid electrolyte instead of organic electrolyte have the advantages of high safety and high theoretical energy density, showcasing great prospects for application. However, the solid-solid interfaces among the components in the composite cathodes have always been a key factor hindering its performance. In order to improve the performance of the interfaces, two in-situ chemical reactions, namely thermal reduction and in-situ growth, were employed to construct conductive and ionic channels on the surface of Li2S. The composite cathodes prepared by the two-step in-situ reaction exhibits superior electrochemical performance, with the utilization rate of Li2S being up to 90% at 0.2 mA cm−2, much higher than that of the composite cathodes prepared by direct mixing. In addition, benefiting from the improvement of the interface and the enhancement of reaction kinetics, the cycle performance and rate performance of the battery with high surface density of active materials only slightly decreased. Specifically, the highest areal capacity of 5.52 mAh cm−2 could be achieved in the battery with Li2S loading of 5.78 mg cm−2, which is much higher than the current criteria for LIBs.