Stabilizing the performance of high-capacity sulfur composite electrodes by a novel gel polymer electrolyte configuration

Increased pollution and the consequent increasing in global warming are drawing attention to the larger use of renewable energy sources such as solar or wind. However, the production of energy from most renewable sources is intermittent and thus relies on the availability of electrical energy storage systems with high capacity and at competitive cost. Lithium-sulfur batteries are among the most promising technologies in this respect due to a very high theoretical energy density (1675 mAh g-1) and that the active material, S, is abundant and cheap. However, a so far limited practical energy density, life time and the scaling-up of materials and production processes prevent their introduction into commercial applications. In this work we report on a simple strategy to address these issues by using a novel gel polymer electrolyte (GPE) which enables stable performance close to the theoreticalof a low cost sulfur-carbon composite with high active material loading, i.e. 70% S. We show that the GPE prevents sulfur dissolution and reduces migration of polysulfide species to the anode. This functional mechanism of the GPE membranes is revealed investigating the Li-anode/GPE interphase at various state of discharge/charge using Raman spectroscopy.