Electronically‐Coupled Nanocarbon/Imidazole Complex as Mediator for Efficient CO ₂ Conversion in a Zn‐CO ₂ Flow Battery

Abstract Metal‐CO 2 battery represents a burgeoning CO 2 utilization technology that combines CO 2 reduction with electricity generation rather than power input, which holds promising applications in the future Mars exploration project. Existing metal‐CO 2 batteries rely heavily on transition‐metal or heteroatom‐doped nanocarbon catalysts to activate CO 2 , which remain challenges of corrosion susceptibility or uncontrollable doping configuration. Herein, it is proposed to design an electronically‐coupled nanocarbon/imidazole ensemble as the mediator to direct CO 2 reduction in a Zn‐CO 2 flow battery. The nanocarbon/imidazole donor–acceptor ensemble is fabricated by coupling butyl imidazole (BI) to a multi‐channel nanocarbon electrode (MCE). The pairing induces intermolecular electron transfer from MCE to the N ‐heterocycle of BI, thus creating an electron‐rich region over BI for efficient CO 2 adsorption and activation. Therefore, under the mediation of the ensemble, the Zn‐CO 2 flow battery can consume CO 2 to co‐generate electricity and CO without the assistance of any transition‐metal or heteroatom‐doped nanocarbon catalysts. In the stimulated Mars atmosphere, the battery can deliver a maximum peak power density of 2.2 mW cm −2 and CO production rate of 3.927 mmol h −1 , comparable to its counterparts using advanced transition‐metal and heteroatom‐doped nanocarbon as the catalytic electrodes.