Red blood cell (RBC)-like Ni@N-C composites for efficient electrochemical CO₂ reduction and Zn-CO₂ batteries

The development of highly active and selective electrocatalysts for the reduction of CO₂ into valuable products presents a promising avenue for addressing the energy crisis and mitigating the greenhouse effect. In this study, we introduce a ligand-assisted supermolecule-derived red blood cell (RBC)-like catalyst composed of nickel and nitrogen-doped carbon (Ni@NC) for electrocatalytic carbon dioxide reduction reaction (eCO₂RR) and Zn-CO₂ battery applications. Among the various samples prepared, Ni@NC-950 exhibited the highest activity and demonstrated a faradaic efficiency of CO (FE_CO) greater than 90% across a wide potential range from −0.6 to −1.0 V [vs. reversible hydrogen electrode (RHE)], with a peak FE_CO of 97.8% achieved at −0.8 V. This translated to a remarkable partial current density (j_CO) of 22.5 mA cm⁻². When employed as the cathode catalyst in a Zn-CO₂ battery, the Ni@NC-950 catalyst delivered a peak power density of 2.36 mW cm⁻² at a current density of 10.97 mA cm⁻². Importantly, the battery exhibited robust long-term discharge capability, operating continuously and steadily at 5 mA cm⁻² for 20 hours.