Towards High‐Performance Zinc‐Based Hybrid Supercapacitors via Macropores‐Based Charge Storage in Organic Electrolytes

Abstract

AbstractZn‐based aqueous supercapacitors are attracting extensive attention. However, most of the reported long‐life and high‐power performances are achieved with low Zn‐utilization (<0.6 %) and low mass loading in cathode (<2 mg cm−2). And, many obtained high energy densities are generally evaluated without considering the mass of Zn‐anode. Herein, we propose a Zn‐based hybrid supercapacitor, involving a metal organic framework derived porous carbon cathode, a Zn‐anode and an N, N‐dimethylformamide (DMF)‐based electrolyte containing Zn2+. We demonstrate that the charge storage of cathode mainly occurs in macropores, showing high rate performance at high mass loading (40 mg cm−2). Furthermore, the aprotic nature of electrolyte and formation of Zn2+‐DMF complex avoid the Zn‐corrosion and dendrite formation. Therefore, the supercapacitor shows a long‐life (9,000 cycles) with a high Zn‐utilization (2.2 %). When calculated with the total mass of cathode (40 mg cm−2) and Zn‐anode, the energy density reaches 25.9 Wh kg−1.