Enabling scalable composite solid electrolyte by cathode-supported scale-up processing

Solid-state lithium metal batteries with poly(ethylene glycol) acrylates (PEGAs) solid electrolytes are considered as one of the promising candidates for next generation power sources. Constructing composite solid electrolytes (CSEs) by adding Li1.3Al0.3Ti1.7(PO4)3 (LATP) particles into PEGAs matrix is a fantastic way to improve the overall electrochemical properties. However, the inorganic LATP particles tend to agglomerate together in the organic PEGAs matrix. Designing LATP into 3D porous oxide electrolyte framework can address the agglomeration issue effectively, but the preparation of the LATP framework is always complicated to operate and difficult to reproduce on a large scale. In this work, a scalable CSE with PEGAs matrix and LATP framework is directly prepared on cathode by integrating with polyvinylidene difluoride (PVDF) and organic solvent, which is friendly to operate and matches the production of the mainstream LIBs. The designed CSE generates a fantastic conductivity of 0.22 mS cm-1 and Li+ transference number (tLi+ = 0.60) at room temperature. The Li/Li symmetric cell with the designed CSE can cycle steadily for 1645 h at 0.1 mA cm-2 and room temperature. Li/LiFePO4 full cells are assembled to assess battery performance, which delivers excellent stable discharge capacity (146.7 mAh g-1 at 0.5 C) and cycling stability with a capacity retention of 96.9% at 0.5 C after 300 cycles at room temperature. The work addresses the issue of hard reproduction of 3D porous oxide electrolyte framework and provides a CSE with 3D porous LATP framework having a high development potential and its feasible scale-up preparation method.