Long-life Li–CO2 cells with ultrafine IrO2-decorated few-layered δ-MnO2 enabling amorphous Li2CO3 growth

Li–CO2 cell recently has captured an increasing interest since it can directly convert chemical energy of greenhouse gas CO2 into electric energy. However, there is still a great challenge to realize long-term cycling of Li–CO2 cell due to the sluggish CO2 reduction/evolution kinetics. In this work, we prepared a highly efficient, ultrafine IrO2-decorated thin-layered δ-MnO2 catalyst (IrO2/MnO2) which was directly grown on carbon cloth. The superior catalytic activity of IrO2/MnO2 enables highly reversible deposition/removal of thin-layered amorphous Li2CO3 on the surface of IrO2/MnO2 nanoflakes, leading to high capacity and long cycle life of the Li–CO2 cells. At 100 mA g−1, Li–CO2 cell with the IrO2/MnO2 catalytic cathode can deliver a high capacity of 6604 mA h g−1. In a capacity-limited charge/discharge mode (1000 mA h g−1), Li–CO2 cell with the IrO2/MnO2 cathode can maintain stable cycling of over 300 cycles at 400 mA g−1. In a full charge/discharge mode over a wide electrochemical window (2–4.5 V), the cell can also maintain stable cycling at high current densities (1070 mA h g−1 remained after 200 cycles at 800 mA g−1).