Li has poor Coulombic (charge) efficiency due to its thermodynamic incompatibility (reactivity) with common organic electrolytes, and it is prone to dendritic structure formation upon repeated cycling which leads to major safety problems. Whilst the former can be tackled by kinetically stable interphase (solid electrolyte interphase, SEI) formation at the Li electrode, the latter can be stopped by reducing the build-up of ion concentration gradient and space charge formation in the electrolyte. Technically, polymeric single Li+ ion conductors (ionomers; with anions fixed to the backbone of the polymer) and inorganic solid state conductors would be ideal solutions, because of their unity Li+ transference number (tLi+ ~1 has been predicted to inhibit dendrite growth mechanism) and high shear modulus, if high ionic conductivities (≥10-4 S cm-1) can be achieved at room temperature. Therefore, we seek to develop novel promising polymeric and inorganic solid ionic conductors with high room temperature ionic conductivity, good kinetic stability with respect to alkali metal (Li/Na) anode, and wide electrochemical stability window, especially for application in Li-O2/Li-S and high voltage cells. In the inorganic phase-space, the aim is to develop novel compounds with dynamically and/or statically disordered structures (superionic conductors); in the polymer space, development of single-ionic conducting membranes based on inexpensive polymers is the primary focus.