DMSO-Li2O2 Interface in the Rechargeable Li-O-2 Battery Cathode: Theoretical and Experimental Perspectives on Stability

摘要

One of the greatest obstacles for the realization of the nonaqueous Li-O-2 battery is finding a solvent that is chemically and electro-chemically stable : under cell operating conditions. Dimethyl sulfoxide (DMSO) is an attractive candidate for rechargeable Li-O-2 battery studies; however, there is still significant controversy regarding its stability on the Li-O-2 cathode surface. We performed multiple experiments (in situ XPS, FTIR, Raman, and XRD) which assess the stability of the DMSO-Li-2-O-2 interface and report perspectives on previously published studies. Our electro-chemical experiments show long-term stable cycling of a DMSO-based operating Li-O-2 cell with a platinum@carbon nanotube core-shell cathode fabricated via atomic layer deposition, specifically with >45 cycles of 40 h of discharge per cycle. This work is complemented by density functional theory calculations of DMSO degradation pathways on Li2O2. Both experimental and theoretical evidence strongly suggests that DMSO it chemically and electrochemically stable On the surface of Li-2-O-2 under the reported operating conditions.