High-Capacity and Long-Life Rechargeable Li–CO₂ Batteries Based on N-Doped Carbon Cathode With High-Loaded Single Ni Atoms

As a novel type of battery for energy devices, Li–CO₂ batteries have a slow kinetic reaction during carbon dioxide reduction and evolution, which leads to problems such as high battery polarization potential, poor cycling performance, and a short lifetime. Therefore, it is important to explore electrocatalysts with high activity and stability. In this study, a novel high-loaded single-atom catalyst was prepared by uniformly anchoring single-atom Ni/Co on N-doped carbon (Ni-NC/Co-NC). Compared with previous reports, the doping amount of Ni is as high as 10 wt%. The Li–CO₂ battery assembled using Ni-NC achieves a high discharge capacity of 51,125 mAh g⁻¹ at 100 mA g⁻¹ current density and displays a low overpotential of 1.63 V after 268 stable cycles (more than 2600 h) at 200 mA g⁻¹ current density. The X-ray absorption fine structure analysis of Ni-NC reveals the presence of Ni and Ni-N₄ sites. Combined with density functional theory calculations, it is found that Ni-NC adsorbs CO₂ reactive species more strongly. Moreover, the electronic synergism of the Ni-N₄ sites can weaken the decomposition barrier of the discharge product Li₂CO₃ and accelerate the reaction kinetic process, thereby enhancing the electrocatalytic activities of CO₂ electroreduction and CO₂ reduction reaction.