High solubility of lithium-polysulfides (Li2Sn) intermediate species in the electrolyte solution in rechargeable lithium-sulfur batteries, results in their reaction with lithium anode to form insoluble lithium polysulfides (PS). These PS sediment on the lithium surface and form new interphase on the lithium anode. Therefore, it is important to investigate the effect of PS dissolution on the reversibility of Li metal stripping/plating. The diffusion of dissolved Li2Sn and their reduction to PS on the anode, poses the biggest challenge toward the realization of practical Li-S batteries. Due to the need of great focus on cathode design and recently anode protection, the aspect of lithium reversibility in presence of PS is remained overlooked. Here, we designed experimental protocols and study the influence of the PS dissolution and crossover, on the reversibility of Li anode by accurately controlling the lithium source in the cell. Using electrochemical, spectroscopic, and microscopic we link between the electrochemical response and the composition and morphology of the deposited layer in presence of PS. Our study revealed the degenerative effect of PS dissolution on the anode side and thus points out the importance of 100% restriction of PS shuttling in order to enable practical reversibility of the metallic anodes.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Surfaces, Coatings and Films
- Renewable Energy, Sustainability and the Environment