Design of Nb₂O₅/graphene hybrid aerogel as polymer binder-free electrodes for lithium-ion capacitors

ABSTRACT

The imbalance between energy density and power density largely limits lithium-ion hybrid capacitor (Li-HEC) advance for various applications. In this work, we report on the construction of a binder-free and porous electrode, which is self-standing T-Nb₂O₅/graphene hybrid aerogels, as Li-intercalating pseudocapacitive electrodes of Li-HECs. The aerogels, with ultrafine T-Nb₂O₅ nanorods (10 ~ 40 nm) uniformly growing on the surface of graphene, feature short lithium-ion transport length, large specific surface area, 3D porous structure and good conductivity, and thus demonstrate both reversible specific capacity (~190 mAh/g at 1 C) and good rate capability (~90 mAh/g at 20 C). Most importantly, Li-HEC devices using activated graphene foam as binder-free cathode can achieve excellent energy densities (53 and 19.7 Wh/kg at power of 355 and 2009 W/kg, respectively) and remarkable cycling performance (capacitance retention of 89% after 3000 cycles), benefitting from good matching between cathode and anode as well as their fascinating microstructures.

KEYWORDS:

• Niobium oxide
• graphene
• hybrid
• aerogels
• lithium-ion capacitors

Acknowledgments

This work is financially supported by the National Natural Science Foundation of China (No. 21603019), Fundamental Research Funds for the Central Universities (No. 2019CDJGFCL004), Natural Science and Foundation of Jiangsu Province (20161005), Key Program for International Science and Technology Cooperation Projects of Ministry of Science and Technology of China (No. 2016YFE0125900), and Hundred Talents Program of Chongqing University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [21603019]; Fundamental Research Funds for the Central Universities [No. 2019CDJGFCL004]; Natural Science and Foundation of Jiangsu Province [20161005]; Key Program for International Science and Technology Cooperation Projects of Ministry of Science and Technology of China [No. 2016YFE0125900] and Hundred Talents Program of Chongqing University.