How to Obtain Reproducible Results for Lithium Sulfur Batteries?

The basic requirements for getting reproducible Li-S battery data have been discussed in this work. Unlike Li-ion batteries, electrolyte-rich environment significantly deteriorates the cycling stability of Li-S batteries assembled and tested under the same conditions. The reason has been assigned to the low concentration of polysulfide-containing electrolyte in the cells, which shows profound influences on both sulfur cathode and lithium metal anode. With optimized sulfur/electrolyte (S/E) ratio of 50 g L−1, a good balance between electrolyte viscosity, wetting ability, diffusion rate of dissolved polysulfide and nucleation/growth of short-chain Li2S/Li2S2 has been established along with largely reduced corrosion of the lithium metal anode. Accordingly, good cyclability, high reversible capacity and Coulombic efficiency are achieved in Li-S cell with optimized S/E ratio without any additive. Other factors such as sulfur content in the composite and sulfur loading in the whole electrode also need careful concern in Li-S battery system in order to generate reproducible results and gauge the various methods used to improve Li-S battery technology.