Strategic Fabrication of Au4Cu2 NC/ZIF-8 Composite Via In Situ Integration Technique for Enhanced Energy Storage Applications

Abstract

Metal–organic frameworks (MOFs), known for their extensive porosity and versatile crystallinity, play a crucial role in the development of advanced energy storage materials. However, their application is limited by stability and conductivity issues. This study addresses these challenges by integrating ultrasmall metal nanoclusters, specifically Au4Cu2 NC, synthesized using a mixed ligand strategy combining 2, 4-Dimethyl benzene thiol (2,4-DMBTH) and 1,2-bis(diphenylphosphino)ethane (dppe). The bimetallic Au4Cu2 NC, characterized by Single Crystal X-Ray Diffraction (SCXRD), is applied to zeolitic imidazolate framework-8 (ZIF-8) using both in situ and ex situ methods to explore their electrochemical and physicochemical properties in energy storage. The in situ Au4Cu2 NC/ZIF-8 composite demonstrated a specific capacitance that is almost two times higher than its ex situ counterpart, attributed to homogeneous dispersion and hence enhanced conductivity. This in situ integration of atomically precise bimetallic nanoclusters on MOFs significantly boosts supercapacitor performance, offering a more effective and reliable solution for energy storage. Further, in practical applications, this device demonstrated an energy density of 87.2 Wh kg−1 at a power density of 1474 W kg−1, highlighting its robustness and potential for high-performance energy storage applications. This approach effectively combats the issue of nanocluster aggregation on substrates, marking a significant progression in supercapacitor technology.