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.