A robust magnesiothermic reduction combined self-activation strategy towards highly-curved carbon nanosheets for advanced zinc-ion hybrid supercapacitors applications

Abstract

Aqueous zinc-ion hybrid supercapacitors are considered to be a newly emerging electrochemical energy storage devices. However, the exploration and design of advanced cathode materials remain a huge challenge. Herein, we developed a versatile one-step magnesiothermic reduction and self-activation process for the synthesis of highly-curved carbon nanosheets (HCCNs) with hierarchical pore structures. In this process, low-molecular weight organic potassium salts (e.g. potassium bitartrate, potassium acetate, potassium oxalate, potassium formate, potassium oleate, potassium sorbate), which usually used as the chemical activating reagents, serve as the carbon source whereas the Mg power acts as the reducing agent. The resulting HCCNs possess hierarchical porosity and unique HCCN geometry which can afford abundant active sites for charge accumulation as well as the highly efficient ions diffusion kinetics. Because of the high ratio of surface-controlled capacitive contribution and high ions diffusion coefficient, the optimized sample can exhibit excellent charge storage performance with an impressive reversible capacity (200.2 mAh g–1), excellent rate capability, and good cyclic stability. The excellent capacitive behaviors combined with the feasible synthetic procedure make the present synthetic protocol a promising choice towards well-designed nanocarbons for electrochemical energy storage applications.