Considerations about the influence of the structural and electrochemical properties of carbonaceous materials on the behavior of lithium-ion capacitors

• Lithium-ion capacitors are promising high power devices.
• Soft carbon is more suitable for application on LICs compared to graphite.
• Soft carbon-based lithium-ion capacitors display higher energy compared to graphite-based devices.

Lithium-ion capacitors (LICs) have attracted an increased attention in the last years. Presently, graphite is the mostly used material for the negative electrodes of LICs. Nevertheless, many works showed that graphite electrodes display rather low performance during high rate charge, as those required for LICs. Therefore the use of alternative carbonaceous anodes could be of importance for the realization of advanced LICs. In this work we show that soft carbon represents a promising alternative to graphite. While the lithium insertion in graphite is hindered every time a new intercalation stage is reached, in soft carbon the lithium insertion process does not show significant decrease over the used potential range. This difference, caused by the different structural properties of these carbonaceous materials, has dramatic consequences on the capacity retention of these carbons during the high rates typically used in LICs.