Engineering carbon quantum dots for zinc ion hybrid capacitors

Zinc ion hybrid capacitors (ZIHCs) integrate two energy storage mechanisms of battery-type electrode and capacitive electrode, bearing the advantages in energy density, power density, and safety.

Until now, the cycle retention rate of ZIHC's capacity reported is still not more than 80%, restricting its development and commercial application severely.

Focusing on the issue, the project aims at overcoming the limitation of traditional electrode materials and re-defining the designing concept to construct Carbon Quantum Dots (C-QDs) for ZIHCs. Advanced methods will be used to harvest carbon quantum dots from coal tar pitch (a sort of industrial solid castoff).

The bulk sp2-carbon network, innumerable edge sites, profuse surface functional groups, and regular size ensures that as-synthesis C-QDs have high electrical conductivity, sufficient ion transport channels and rich adsorption sites.

Moreover, the new concept of dynamic evolution is introduced for insight into the structure and interface failure of ZIHC's electrode. The interface-reconstruction mechanism and the attenuation model of capacity will be established for the first time. Further, the methods to strengthen structures of C-QD electrode will be developed based on a trade-off strategy.

The ultimate goal is to improve the energy storage efficiency of ZIHCs by 20% and to increase their cycle performance more than 95% unprecedentedly. This research will develop long-running high performance ZIHCs, for contributing European energy storage industry.

The ER will achieve abundant research experience and scientific skills from the project and the capability to launch her own research group in future.