Redox Mechanisms and Film Formation at Interfaces in Lithium-sulfur Battery System

The lithium-sulfur battery is widely considered as one of the most perspective post lithium-ion systems. However, the high theoretical capacity of 1672 mAh g -1 is difficult to attain in practice. Also, the typical power capability lags behind that of the Li-ion rivals. We will present extensive experimental work using many different types of electrochemical cells and different measuring techniques with the aim to elucidate the main processes taking place at two interfaces: lithium/electrolyte and electrolyte/carbon cathode. We will identify the main electrochemical reaction show how they directly or indirectly limited the performance of state-of-the-art Li-S systems. Selected typical results will be interpreted based on modeling using the transmission line approach. New insights into well known mechanisms such as deposition of solid film, depletion of polysulfides in bulk electrolyte, the shuttle effect etc. will be presented and discussed.