A polymer hybrid solid electrolyte that possesses high room temperature ionic conductivity, very low interfacial resistance with the electrodes and electrochemical stability window up to 5.2 volts. The polymer-ceramic hybrid solid electrolyte includes: a PEO based copolymer electrolyte; a solvate ionic liquid (SIL); and a salt of a monovalent cation. The inclusion of an ionically conductive additive, such as a ceramic fine powder, can further improve ionic conductivity as well as mechanical properties.