Electroreductive carboxylation of graphite with CO2 for lithium–sulfur batteries with boosted performance

Owing to the excellent chemical/thermal stability, it is difficult to induce surface modification in graphite, which limits its wider application in rechargeable batteries. To solve this problem, a feasible strategy is to introduce oxygen-containing functional groups on the graphite surface. However, it is challenging to selectively introduce only carboxyl groups by conventional synthetic methods. Herein, we report a new method for the synthesis of carboxyl graphite via the electroreductive carboxylation of graphite with CO₂. When this carboxyl graphite is employed as a sulfur host for lithium-sulfur (Li-S) batteries, the electrochemical performance is significantly improved compared to that with a conventional graphite host.