High-performance all-solid-state batteries enabled by salt bonding to perovskite in poly(ethylene oxide)

Significance Use of a flexible solid polymer electrolyte is a common strategy to obtain an all-solid-state lithium battery of high stored electric power at acceptable charge–discharge cycling rates. Commercial realization of this strategy with poly(ethylene oxide) containing a garnet ceramic has been unsuccessful and dendrites form and grow across garnet electrolytes without proper treatment of the garnet surface. We report that use of a perovskite Li + electrolyte in place of the garnet ceramic provides an adequate Li + conductivity at 25 °C without dendrite formation. We also demonstrate a binding of the TFSI − anion of a LiTFSI [lithium bis(trifluoromethanesulfonyl)imide] salt to the polymer, which increases both the Li + conductivity and the Li + transport number.