A solid ionic electrolyte having a neutral organic plastic crystal matrix doped with an ionic salt may be used in an electrochemical device having an anode comprising a Li-containing material having an electrochemical potential within about 1.3 V of lithium metal. Electrochemical devices are disclosed having a cathode, an anode of a Li-containing material having an electrochemical potential within about 1.3 V of lithium metal, and a solid ionic electrolyte having a neutral organic plastic crystal matrix doped with an ionic salt. Such devices have high energy density delivery capacity combined with the favorable properties of a neutral organic plastic crystal matrix such as succinonitrile.