The Li-O/CO battery with high capacity has recently been proposed as a new protocol to convert CO. However, the fundamental mechanism for the reaction still remains hazy. Here, we investigated the discharge processes of Li-O/CO (70%/30%) batteries in two solvents, dimethyl sulfoxide (DMSO) and 1,2-dimethoxyethane (DME). During discharge, both solvents initially show the reduction of oxygen. However, afterward, the solvent affects the reaction pathways of superoxide species by solvating Li with different strength, depending on the so-called donor number. More precisely, the initial formation of CO is favored in DMSO at the expense of lithium superoxide formation that we observed in DME. Despite the different intermediate processes, X-ray diffraction showed that LiCO was the final discharge product in both solvents. Moreover, we observed that CO cannot be reduced within the electrochemical stability window of DMSO and DME.

The production of hydrogen at a large scale by the environmentally-friendly electrolysis process is currently hampered by the slow kinetics of the oxygen evolution reaction (OER). We report a solid electrocatalyst α-Li 2 IrO 3 which upon oxidation/delithiation chemically reacts with water to form a hydrated birnessite phase, the OER activity of which is five times greater than its non-reacted counterpart. This reaction enlists a bulk redox process during which hydrated potassium ions from the alkaline electrolyte are inserted into the structure while water is oxidized and oxygen evolved. This singular charge balance process for which the electrocatalyst is solid but the reaction is homogeneous in nature allows stabilizing the surface of the catalyst while ensuring stable OER performances, thus breaking the activity/ stability tradeoff normally encountered for OER catalysts.