Construction of high-performance asymmetric supercapacitor based on FeCo-LDH@C3N4 composite electrode material with penetrating structure

The layered structure of layered double hydroxides (LDH) is the key to its use as an electrode material, however, the lack of efficient charge exchange between layered structures severely limits the application of LDH in supercapacitors. In this work, FeCo-LDH was composited with C3N4 by hydrothermal method, and a penetrating structure was built using the layered structure of the two materials. The penetrating structure provides a channel for charge transfer between FeCo-LDH layers and also solves the self-stacking problem of C3N4. The structure of the composites was explored by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscope (TEM), and the results showed that FeCo-LDH composited with C3N4 and formed a penetrating structure. In addition, the electrochemical behavior of the electrode material was evaluated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). Electrochemical test results show that it has a high specific capacity (593 C g−1) at 1 A g−1. Furthermore, in order to study the energy storage properties of the composites, the optimal composites were designed as positive electrode as asymmetric supercapacitors, and the designed asymmetric supercapacitor still has a retention rate of 83.72 % after 10,000 cycles. This attractive performance reveals that FeCo-LDH@C3N4 could as an electrode material for high-performance supercapacitors.