Porous carbon spheres anode with the stable output of low delithiation plateau and constant delithiation ratio for lithium ion hybrid capacitor

Abstract

Porous carbon spheres derived from the facile hydrothermal treatment associated with the calcination process exhibit the good spherical morphology and unique porous structure. For the Li-based half-cell test, porous carbon spheres electrode not only exhibits larger reversible capacities and better compatibility as compared to the widely-used graphite, but also provides stable delithiation plateaus under different current density. Additionally, the delithiation ratio below 1V almost accounts for a constant value (around 70%) with the increase of current density, evidencing that Li intercalation storage is the dominant model and Li insertion/extraction processes are propitious. The lithium ion hybrid capacitor configured with S-doped mesoporous graphene and porous carbon spheres as cathode and anode, delivers satisfied energy and power densities (up to 177Whkg−1 and 12,303Wkg−1, respectively) as well as long-term cyclability, which is superior to the corresponding S-doped mesoporous graphene//graphite and activated carbon//porous carbon spheres. In addition, the developed synthesis strategy is in favor of the realization of the scalable production of porous carbon spheres.