Electrochemical parameterization of commercial activated carbons as anodes for high-power Li-ion batteries

Abstract

Activated carbons play an important role in enabling Li-ion batteries for high-power applications. They are well established in the application side of energy storage but remain untouched for integration toward conceptualization. As conceptualization attracts growing interest in the field of energy storage, more work needs to be done to bridge the gap between application and concept. Being a part of closing the gap between experiment and modeling, an electrochemical parameterization of commercial activated carbons having different specifications was investigated within the present study. The apparent Li-ion diffusion coefficient and exchange current density of different activated carbons were calculated. Results confirmed that the Li-ion diffusion coefficient was promoted by the ordered structure. Electronically conductive activated carbons exhibited low charge-transfer resistance and, hence, high exchange current density. Besides, long-term capacity retention is strongly linked with the activated carbons' degree of structural order. According to the simulated discharge capacities extracted from the simplified 1D full-cell model with LiMn2O4-Activated Carbon cell chemistry, a notable improvement was observed in comparison with reference LMO-Graphite systems at all C-rates. Nevertheless, activated carbons proved their significance at especially high rates. When 20C was applied, a strong correlation can be built with the long-term cyclic behavior of activated carbon half-cells.