Microstructure engineering of solid-state composite cathode via solvent-assisted processing

摘要

Microstructure engineering of composite cathodes in all-solid-state batteries is critical to ensure efficient electronic and ionic percolation networks. Organic-based solid-state batteries have recently emerged with impressive material-level specific energy and cycling stability. However, the low mass fraction of active materials in state-of-the-art organic cathodes severely limits electrode-level specific energy. In this work, we reveal the unfavorable microstructure as the origin of poor performance at a high fraction of active materials; a solvent-assisted process is then devoted to rectifying the microstructure, increasing the active materials fraction from 20 to 40 wt % while maintaining high utilization (97.6%). The resulting electrode-level specific energy of 302 Wh kg−1is 83% higher than state-of-the-art solid-state batteries with organic cathodes. On the basis of the unique interphase chemistry between pyrene-4,5,9,10-tetraone and lithium thiophosphate, a potential-dependent reversible interphase evolution model is proposed. This work illustrates the critical role of microstructure engineering in optimizing novel active materials for all-solid-state batteries.