Inverting the Triiodide Formation Reaction by the Synergy between Strong Electrolyte Solvation and Cathode Adsorption for Lithium-Oxygen Batteries.

Authors :: Zhang XP
Li YN
Sun YY
Zhang T
Source :: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2019 Dec 16; Vol. 58 (51), pp. 18394-18398. Date of Electronic Publication: 2019 Nov 06.
Publication Year :: 2019
Abstract: An exceptionally strong solvation effect of dimethyl sulfoxide (DMSO) on I <subscript>2</subscript> is identified by the largest shift observed so far of the I <subscript>2</subscript> Raman peak with respect to I <subscript>2</subscript> vapor and by elongated I-I bond lengths in first-principles molecular-dynamics simulations. This effect together with strong binding by an RuO <subscript>2</subscript> surface to I <subscript>2</subscript> is found to invert the direction of the reaction I <superscript>-</superscript> +I <subscript>2</subscript> ⇌I <subscript>3</subscript> <superscript>-</superscript> to the left-hand side. Inspired by this finding, we prepared a Li-O <subscript>2</subscript> battery with the Li/DMSO+LiI/RuO <subscript>2</subscript> structure. The synergic action of DMSO and RuO <subscript>2</subscript> on I <subscript>2</subscript> is found to suppress the shuttle effect of the redox mediator (RM) by anchoring I <subscript>2</subscript> molecules, the oxidation product of the RM. Significantly enhanced stability is demonstrated over 100 cycles at charging voltage below 3.65 V.<br /> (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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