Dry-processed thick cathodes in polymer-based solid-state lithium-ion batteries

The exceptional specific energy in all-solid-state lithium-ion batteries (ASSLBs) is partially evoked by employing high-areal-loading composite cathodes, in which ideal merits include elevated loading fraction of active materials, thickness over 100 μm, and operation without stack pressure. Development of such advanced composites is of significance yet remains challenging, owing to unresolved issues tackled by effective contact loss between solid particles during electrochemical cycling. Here we apply hybrid polymers as electrolyte and binder that are compatible with cathode active materials (CAM) to drive a novel dry fabrication in building a homogenous high-areal-loading cathodes. This approach facilitates the fabrication of thick cathodes up to 300 μm with robust electrolyte-cathode interfaces and continuous ionic conduction pathways. The resultant Li4Ti5O12||LiNi0.6Co0.1Mn0.3O2 (NCM613) full cells deliver high current density (1.2 mA cm−2), promising areal capacity (2.7-6.9 mAh cm−2, NCM613 mass loadings of 15.3-43.3 mg cm−2), and long cycle life (500 cycles) with a capacity retention of > 90% under zero stack pressure. The results demonstrate a scalable polymer-based route for developing ASSLBs with strong electrochemical resilience through synergistic integration of cathode materials by soft/hard hybrid interfaces.
This approach eliminates particle shedding and cracking inherent to wet-processed thick electrodes, enables stable operation of high-loading full cells without external pressure. The system's safety is ensured by polymers' intrinsic flame retardancy and the flammability-free solid-state architecture. Combined with the cost-effectiveness of polymer electrolytes and our high-loading fabrication protocol, surpassing existing literature, this work unlocks a promising new route for practical all-solid-state polymer lithium batteries. Collectively, these breakthroughs address fundamental industrialization requirements for high-energy-density systems.