High energy-power Zn-ion hybrid supercapacitors enabled by layered B/N co-doped carbon cathode

Abstract

Zinc-ion hybrid supercapacitors (ZHSs), inheriting the merits from supercapacitors and many batteries, exhibit promise in energy storage technologies. However, they are bottlenecked by the sluggish diffusion of Zn2+, Zn dendrite growth and inadequate cathodes. Herein, newly designed layered B/N co-doped porous carbon (LDC) guided by the intercalator is proposed for the first time as cathode material for high-energy-power ZHSs to efficiently mitigate these issues. Associated with the multiple synergy of short mass/charge transfer pathway, fast kinetics and increased electroactivity endowed by the structurally engineered LDC, the quasi-solid Zn//gelatin/ZnSO4 (gel)//LDC ZHS device exhibits intriguing Zn-storage capabilities, including exceptional energy/power density of 86.8 Wh kg−1/12.2 kW kg−1 in a relatively wide voltage window of 0.2–1.8 V, long service life of 6500 cycles at 5 A g−1 and low self-discharge. Moreover, smart watch and LED indicator can be driven well by this device. The present results highlight the facile and efficient synthesis of a layered carbon-based cathode material, significantly contributing to the rapid development of eco-friendly and scalable Zn-based hybrid energy devices.