Heterostructured Co-NTC@Co3S4 as an anode material for asymmetric pseudocapacitors

Abstract

Herein, a composite structure of ZIF-67@Co-NTC was synthesized by using ZIF-67 as a sacrificial template and rigid 1,4,5,8-naphthalenetetracarboxylic acid (NTC) as a linking ligand, and it was partially vulcanized to form layer-like Co₃S₄ nanosheets to finally successfully synthesize a composite heterostructure of Co-NTC@Co₃S₄. In the process of charge and discharge, the layered structure can improve the electron transport efficiency and prevent the accumulation of the nanosheets. Based on these advantages, Co-NTC@Co₃S₄ exhibits excellent electrochemical properties. It can reach 3117.3 F g⁻¹ at 1 A g⁻¹, and the magnification capacity is about 80% at 10 A g⁻¹; meanwhile, after 1000 cycles, the retention rate can reach up to 87% at this current density. A hybrid supercapacitor composed of Co-NTC@Co₃S₄ and AC (activated carbon) exhibits ideal performance; for example, the cycle performance can reach up to 110% after 5000 cycles (10 A g⁻¹). The excellent electrochemical properties indicate that Co-NTC@Co₃S₄ is a promising electrode material in the field of energy storage. This work provides general tactics that would realize the potential of the derivatives of ZIF@MOFs as high-performance electrode materials.