In Situ Localized Polysulfide Injector for the Activation of Bulk Lithium Sulfide.

The activation of commercial Li2S remains to be one of the key challenges against its commercialization as a starting cathode material for a sulfur-based Li-ion battery system. In this work we take advantage of the lower oxidation potential of commercial Na2S (1-3 wt%) to serve as an in situ and local polysulfide injector for the activation of commercial Li2S (70 wt%). In contrast to applying pre-solvated redox mediators, this technique allows for the activation of commercial Li2S at lower voltages with an electrolyte content as low as 3 μL mg-1Li2S at 3 mgmgLi2S cm-2 and 4 μL mg-1Li2S at 6.5 mgLi2S cm-2 without any other material modification.