In 1992, Bellcore researchers demonstrated the feasibility of a liquidelectrolyte Li-ion system based on the Li1 + xMn2O4/C redox couple which presents cost and environmental advantages over the LiCoO2/C system. However, neither of these systems are free of the risk of electrolyte leakage. To address this problem, we investigated various means of trapping the liquid electrolyte in a polymer matrix and developed the first practical plastic Li-ion battery. In this paper we compare the performance and scaleability of this technology to those of its liquid Li-ion counterpart. Based on the “hybrid polymer” concept, this battery exhibits excellent cycle life (more than 2500 cycles) and good rate capabilities (the battery can deliver 95% of its total capacity at a 1C discharge rate). This technology is compatible with various positive (LiMn2O4, LiCoO2 and LiNiO2) and negative (carbon, graphite) electrode materials.