Synthesis of electrospun NASICON Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte nanofibers by control of germanium hydrolysis

We report the synthesis of ceramic Li1.5Al0.5Ge1.5(PO4)3 (LAGP) nanofibers by combining sol–gel and electrospinning techniques. A homogeneous and stable precursor solution based on chlorides was achieved by controlling Ge hydrolysis. Subsequent electrospinning and heat treatment resulted in highly porous nanostructured NASICON pellets. After a full chemical-physical characterization, various amounts of LAGP nanofibers were used as a filler to develop polyethylene oxide (PEO)-based composite electrolytes. The addition of 10% LAGP nanofibers has allowed doubling the ionic conductivity of the plain polymer electrolyte, by providing longer ion-conductive paths and reducing PEO crystallinity. These findings are promising towards developing solution-based synthesis approaches featuring Ge precursors. In addition, the achieved LAGP nanofibers proved to be a promising nanofiller candidate to develop composite electrolytes for next-generation solid-state batteries.