Targeted anchoring of Cu sites in imine-based covalent organic frameworks as catalytic centers for efficient Li–CO2 batteries†

Abstract

Lithium–carbon dioxide (Li–CO₂) batteries have attracted much attention due to their high theoretical energy density and reversible CO₂ reduction/evolution process. However, the wide bandgap insulating discharge product Li₂CO₃ is difficult to decompose, leading to large polarization or even death of the battery, thus seriously hindering the practical application of Li–CO₂ batteries. The properties of covalent organic framework (COF) materials, which can support the construction of multiphase catalytic systems, have great potential in the fields of CO₂ enrichment and electrocatalytic reduction. In this paper, the excellent redox properties of transition metal were utilized to introduce Cu metal into an imine-based COF to form Cu–O,N sites as the active sites for CO₂ oxidation and reduction. The electrochemical performance of the Cu sites in Li–CO₂ batteries was investigated, and the prepared batteries were able to cycle stably at a current density of 200 mA g⁻¹ for more than 1100 h. COF structural sites can be anchored by metal Cu sites to form Cu–O,N active centers for CO₂ oxidation and reduction processes. This study provides a new approach for the development of lithium CO₂ batteries towards more stable and stable.