Several network-based polymer electrolytes provide both thermal, mechanical and redox stabilities, while insuring a high conductivity level. Linear unsaturated polyether precursors may be obtained either by step-growth polymerization from oligomeric polyethers or by ring-opening polymerization from oxirane mixtures. In addition, theoretical investigations on several lithium salts are presented, which allowed optimized geometries as well as charge densities to be established in the gas phase.