High-performance Li-CO2 batteries enabled by synergistic interaction of iron dopant-modulated catalysts and nitrogen-modified substrates

Abstract

Efficient CO2 electrodes require optimized catalytic activity and a delicate electrode structure. However, it is often insufficient to consider only a single factor when constructing a high-performance electrode. In this study, we elaborately prepare the freestanding Fe-doped CoP catalysts on N-doped carbon cloth (Fe-CoP@N-CC) substrates, which synergistically realizes electronic structure tuning of the catalysts and electrode structure modification. The experimental and theoretical calculations reveal that the electrode structure, consisting of fully covered nanowires on an N-CC skeleton, promotes mass transfer and accommodates products. The introduction of N atoms in Fe-CoP@N-CC leads to increased defects and strong Co–N–C bonds at the interface, enhancing interfacial electron transfer. Furthermore, Fe doping optimizes the electronic structure of Fe-CoP@N-CC. This synergistic enhancement facilitates the kinetics of both CO2 reduction reaction (CO2RR) and CO2 evolution reaction (CO2ER), resulting in the formation of large-size spherical morphologies following the solution pathway. The improved electrocatalytic performance of Fe-CoP@N-CC electrodes was demonstrated by their high discharge capacity of 4127 mAh g−1 and cycling stability of 446 h in Li–CO2 batteries. These findings emphasize the significance of compatibility between electrode structure and catalytic activity in the design of CO2 electrode.