Achieving Highly Stable Solid-State Lithium Batteries by Combining High-Ceramic Composite Electrolytes with Thermopolymerized Gel

Solid-state lithium-ion batteries have advantages in safety over liquid batteries due to their excellent thermal stability, nonflammability, and outstanding mechanical properties. Polyvinylidene fluoride (PVDF)-based composite solid electrolyte has attracted great attention because of its high ion conductivity, high mechanical strength, and high electrode compatibility. However, it faces the problem of residual DMF solvent during the preparation process. DMF undergoes side reactions with the Li metal anode at the interface, which weakens the cycle life of the battery. This work reduces the content of residual DMF in composite electrolytes by increasing the ceramic content at the source, which improves the interface stability of the electrolyte and the Li metal anode. Moreover, the large mechanical strength originating from the high ceramic content enables the composite electrolyte to exert additional resistance against the growth of lithium dendrite. At the same time, it combines a thermally polymerized gel to decrease the interface contact problem caused by the increase in the ceramic content. This strategy successfully improves the interface stability and achieves good interface contact. As a result, the batteries with a high ceramic content electrolytes display a higher capacity retention rate and better rate capability than those with low ceramic content electrolytes.