Ammonium salts are demonstrated as effective additives to promote the dissolution of Li2S (up to concentrations of 1.25 M) in DMSO solvent at room temperature through hydrogen binding between N-H groups and S2– anions.
Significance and Impact
Dissolving Li2S in an organic electrolyte is a facile solution to maintain the active reaction interface between an electrolyte and a sulfur cathode, and thus addresses the issue of uncontrollable passivation of electrodes by highly insulating Li2S that limits sulfur utilization, increases polarization, and decreases cycling stability in Li-S batteries.
- Different ammonium salts were identified as effective additives for dissolving Li2S as well as other short chain polysulfides.
- NMR measurements and DFT simulations reveal strong interactions between NH4+ and S2– via hydrogen bonding (N―H····S2-) that facilitates the dissolution of Li2S.