Design of an ultralong-life Li-CO2 batteries with IrO2 nanoparticles highly dispersed onto Nitrogen-doped Carbon Nanotubes
Li-CO2 batteries have gained tremendous popularity since they not only can realize the eco-friendly utilization of greenhouse gas CO2, but also offer high theoretical energy density. However, they still suffer from several problems, such as high overpotential and poor cycling life. High-efficiency electrocatalysts for carbon dioxide reduction and Li2CO3 decomposition play a critical role in Li-CO2 batteries. In this work, the nitrogen-doped carbon nanotubes modified with ultrafine IrO2 nanoparticles (IrO2-N/CNT) were introduced into the cathode of the Li-CO2 batteries. The batteries with IrO2-N/CNT cathode exhibited high specific capacity (4634 mA h/g), low charge platform and low overpotential (3.95 V/1.34 V), and ultralong cycling life (more than 2500 h/316 cycles at 100 mA/g with the fixed capacity of 400 mAh/g). It is speculated that the high performance of the IrO2-N/CNT cathode is closely related to the super catalytic activity of highly dispersed ultrafine IrO2 nanoparticles and the nitrogen-doped carbon nanotube network, which is not only enhancing the electron conductivity and the capture ability of CNT to Li atoms/CO2, but also promoting reaction between Li+/CO2 and C/Li2CO3. This work paves a promising way to deploying an efficient cathode catalyst for the ultralong-life Li-CO2 batteries.