Anion intercalation enables efficient and stable carboxylate upgrading via aqueous non-Kolbe electrolysis.

Next-generation techniques for sustainable carboxylate production generate carboxylate salts as the primary outcome. To circumvent the costly conversion of carboxylate salts to acids, we demonstrate the aqueous (non-)Kolbe electrolysis process as an alternative strategy to generate downstream value-added chemicals. Upon revealing the irreversible oxidation-induced charge transfer inhibition on the graphite anode, we propose an anion intercalation strategy to mitigate the stability problem induced by the ever-increasing overpotential. In acetate decarboxylation, we observe a high Faradaic efficiency of ~95% for non-Kolbe products (methanol and methyl acetate) at wide current densities ranging from 0.05 to 1 A cm-2 and long-term stability at current densities of 0.15 and 0.6 A cm-2 for 130 and 35 h, respectively. We also extended this strategy for the upgrading of long-chain carboxylates such as propionate, butyrate, and succinate. Our work provides valuable guidance for carboxylate upgrading and extendable strategy for overcoming passivation challenges in catalysis.