From wasted polymers to N/O co-doped partially graphitic carbon with hierarchical porous architecture as a promising cathode for high performance Zn-ion hybrid supercapacitors

Abstract

Zn-ion hybrid supercapacitors (ZIHSCs) inheriting the superiorities of high power and energy densities from supercapacitors and batteries are considered as a prospective competitor in renewable energy storage systems. However, their development suffers from the impediments of sluggish reaction kinetics and inadequacy of cathode materials. The conversion of recycled carbon precursors into low cost porous carbon-based cathodes is a wise strategy to pursue high performance ZIHSCs. Herein, a N/O co-doped partially graphitic carbon with hierarchical porous scaffolding architecture is constructed via an effective and scalable method by using wasted polymers of spent disposable blue nitrile gloves as a carbon source. The coordination of these features affords extensive active sites for charge capture and a rapid mass/charge transfer route for fast kinetics, thus bringing out high electrochemical performance for the aqueous ZIHSC device (an ultrahigh specific capacity of 257.9 mA h g⁻¹ at 0.1 A g⁻¹ with a significant capacity retention of 117.4 mA h g⁻¹ at 50 A g⁻¹, marvelous energy and power densities of 226.5 W h kg⁻¹ and 47.1 kW kg⁻¹, and a reliable cyclability of 97.8% after 15 000 cycles at a high current density of 20 A g⁻¹). Importantly, the as-assembled quasi-solid ZIHSC device also displays superb Zn²⁺ storage capability of 219.0 mA h g⁻¹ at 0.1 A g⁻¹ with a capacity conservation of 61.2 mA h g⁻¹ at 20 A g⁻¹ and a high energy density of 186.7 W h kg⁻¹, together with low self-discharge and good mechanical flexibility. These data in this work indicate the rational design of advanced carbon materials from wasted carbon sources can turn trash into treasure in the energy storage field.