Synergistic effects of fluorine plasma on improving carbon aerogel anodes performance in lithium-ion batteries

Abstract

In this study, CF4 plasma was used to increase the lithium-ion storage performance of carbon aerogels. We confirmed the impacts of the fluorine plasma on the chemical and structural properties of F-doped carbon aerogels. Analyses of various battery performances revealed significant enhancements in the specific discharge capacities, rate performances, and cycling stabilities. These enhancements were attributed to a synergistic effect of F-doping and increased specific surface areas caused by the fluorine plasma. The increased capacities arose from plasma-induced increases in the specific surface areas, facilitating greater lithium-ion adsorption. Faster rate performances were achieved through increased conductivities due to the formation of semi-ionic C–F bonds and optimized pore structures that increased electrolyte permeability. The superior cycling stability was attributed to the stable LiF-based SEI layer generated by semi-ionic C-F bonds. These findings were confirmed by analyses of the lithium-ion storage mechanism and the postcycling SEI layers. These results showed that the F-doped carbon aerogel anodes prepared with the plasma treatments had higher discharge capacities, faster rate performances, and higher stabilities due to the synergistic effect of F-doping and etching.