Construction of MOFs with different dimensions and bimetallic effect for enhanced electrochemical performance

Designing and constructing bimetallic organic framework nanostructures is an effective method to improve supercapacitor materials. In this paper, Metal-organic frameworks (MOFs) are generated from different carboxylic acid ligands with nickel nitrate. The Ni BTC (nickel 1,3,5-benzenetricarboxylate) MOF electrode material exhibits excellent electrochemical performance. A series of bimetallic (Ni/Co) MOFs were synthesized by incorporating cobalt ions. Among them, Ni/Co-MOF-7:1 (with an optimal Ni/Co ratio of 7:1) demonstrates the best performance. Consequently, the optimized Ni/Co-MOF-7:1 exhibits a remarkable capacitive property of 755 F·g⁻¹ at 0.5 A·g⁻¹ and the material retains 81.6% of its initial capacity after 5000 cycles. Asymmetric supercapacitors assembled with Ni/Co-MOF-7:1 and activated carbon demonstrate an exceptional capacitive behavior of 235.7 F·g⁻¹ at 0.5 A·g⁻¹, and maintaining 97.9% of their initial capacitance after the 5000 cycles at 5 A·g⁻¹.