Rational Design of Nanostructured Metal/C Interface in 3D Self‐Supporting Cellulose Carbon Aerogel Facilitating High‐Performance Li‐CO₂ Batteries

Abstract The sluggish kinetics of CO₂ reduction and evolution reaction (CRR and CER) on the Li–CO₂ battery cathode seriously hindered its practical application. Rational design of the Ru/C interface is expected to simultaneously decrease the free energy barrier of intermediate species and create a favorable electronic structure, effectively promoting the catalytic reaction kinetics of the CRR and CER. Herein, a 3D self‐supporting cellulose carbon aerogel (CCA) with well‐defined Ru/C interfaces (Ru@CCA) is synthesized as an advanced CO₂‐breathing cathode for Li–CO₂ batteries. The results show that the energy efficiency significantly improves to 80% with a high discharge capacity of 10.71 mA h cm⁻² at 20 µA cm⁻², and excellent cyclic stability of 421 cycles at 100 µA cm⁻². These outstanding performances are highly competitive compared with state‐of‐art Li–CO₂ cathodes. In addition, the unique interface design strategy is applied to other non‐noble metal@CCA cathodes, which confirms the advantages of constructing nanostructure metal/C interfaces for improving the kinetics of CRR and CER. This fundamental understanding of the structure–performance relationship provides new inspiration for designing highly efficient cathode catalysts for Li–CO₂ batteries.