Lithium solid-state composite electrolytes (LiSCEs) provide the opportunity for long life spans, low self-discharge, high reliability, high energy density, and safety. Additionally, this class of electrolytes can be used in electrolytically formed solid-state batteries (EFBs), which may promote reductions in cell manufacturing costs due to their simplicity of design and permit the formation of batteries with diverse architectures. Herein, we provide a discussion of LiSCEs, highlight some of the recent progress in EFB development, and present a forward outlook.