Improvement of Lithium Anode Deterioration for Ameliorating Cyclabilities of Non-aqueous Li-CO2 Batteries
Herein, ruthenium (Ru) nanoparticles were anchored on carbon nanotube (Ru/CNT) functionalized as catalyst cathodes for non-aqueous Li-CO2 cells. For cycling tests through a low cut-off capacity (100 mAh g-1), the origin of battery deterioration resulted from the accumulation of Li2CO3 discharging products on catalytic surfaces, identical to observations in previous studies. However, the Li-CO2 cells in this presented work showed a sudden death within several cycles of high cut-off capacity (500 mAh g-1), and no Li2CO3 residues were investigated on the cathode. By contrast, Li dendrites and passivation materials (LiOH and Li2CO3) generated on Li anode upon cycling at the limited capacity of 500 mAh g-1, which dominantly contributed to the battery degradation. A Li foil-replacement method was adopted to present that Ru/CNT cathode performed accumulative 100 cycles under the cut-off capacity of 500 mAh g-1. These results demonstrate that not only Li2CO3 residues blocking on active sites of cathode but also Li dendrite and passivation materials producing on the anode caused Li-CO2 battery deterioration. Moreover, in the present work, a carbon thin film was deposited on Li metal (C/Li) by a sputtering system for suppressing the dendrite formation upon cycling and promoting the defense of H2O attack from the electrolyte disintegration. The Li-CO2 cell with Ru/CNT catalyst and C/Li anode revealed improved electrochemical stability of 115 cycles at the limited capacity of 500 mAh g-1. This proto strategy provided a significant research direction focusing on Li anode for elevating the Li-CO2 battery durability.