Hierarchical CoMn-LDH and Heterostructured Composites for Advanced Supercapacitors and Electrocatalysis Applications

Area of Science:

• Materials Science and Engineering
• Electrochemistry
• Nanotechnology

Background:

• Layered double hydroxides (LDHs) are promising materials for energy storage and catalysis.
• Developing efficient and stable electrode materials is crucial for advanced electrochemical devices.
• Hierarchical nanostructures can enhance the performance of energy storage and catalytic materials.

Purpose of the Study:

• To synthesize and characterize novel hierarchical CoMn-LDH and its heterostructures (CoMn@CuZnS, CoMn@CuZnFeS).
• To evaluate the bifunctional application of these materials as supercapacitor electrodes and electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER).

Main Methods:

• Hydrothermal synthesis of CoMn-LDH.
• Fabrication of CoMn@CuZnS and CoMn@CuZnFeS heterostructures.
• Electrochemical characterization using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.
• Electrocatalytic activity testing for OER and HER.

Main Results:

• CoMn-LDH exhibited superior areal capacitance (5.323 F cm⁻²) and specific capacitance (279.49 mAh/g) at 4 mA cm⁻².
• The AC//CoMn-LDH hybrid supercapacitor showed remarkable stability, retaining 63% capacitance over 20,000 cycles.
• CoMn-LDH, CoMn@CuZnS, and CoMn@CuZnFeS demonstrated efficient OER and HER catalysis with low overpotentials.
• CoMn-LDH displayed favorable Tafel slopes (102 mV/dec for OER, 128 mV/dec for HER) and good stability.

Conclusions:

• The synthesized CoMn-LDH and its heterostructures are effective bifunctional materials for supercapacitors and OER/HER electrocatalysis.
• CoMn-LDH shows exceptional performance as a supercapacitor electrode with high capacitance and stability.
• The materials present a promising pathway for developing advanced energy storage and conversion systems.