Metal–Organic Framework/Ti3C2Tx MXene-Derived Functional Nanostructures for High-Performance Supercapacitors

For better charge storage and rate performance, supercapacitors need unique electrode materials and design architectures. Recent interest in metal–organic frameworks (MOFs) stems from their chemical compatibility with host materials and the abundance of active sites. However, their direct use as electrode materials has been difficult due to their limited electrical conductivity and excessive agglomeration, making them poor electrochemical performers. To solve these problems and boost the performance, we synthesized a nanoporous carbon-based electrode with metallic cobalt nanoparticles and MXenes. The electrode material is a zeolite-imidazole framework (ZIF)-67-derived cobalt-based nanoporous carbon nanotube (CNT) composite produced via in situ growth on Ti3C2Tx MXene flakes by pyrolysis under inert conditions. In situ synthesized porous CNTs add porosity and interconnecting channels to the MXenes providing increased sheet ion transport and diffusion, improving the electrochemical performance. This lowered the charge resistance to 3.73 Ω and enhanced the MXene nanosheet Bode phase angle. In an aqueous acidic electrolyte, the MXene-nanoporous CNT composite exhibited a nominal capacitance of 1605 F/g and 94.5% charge retention after 5000 cycles.