Highly scalable and pH stable 2D Ni-MOF-based composites for high performance supercapacitor

Supercapacitors are projected as one of the most promising candidates for next-generation energy storage devices. Herein, we strategically developed a microporous two-dimensional Ni-metal organic framework (MOF: IITKGP-20A, IITKGP stands for the Indian Institute of Technology Kharagpur) which is highly scalable and thermodynamically stable over a wide pH range (2-10), intended for energy storage applications. Graphene oxide (GO) with different wt% (3, 5, and 7) was introduced with the MOF precursors to form in-situ MOF@GO composites (IITKGP-20A-GO3, IITKGP-20A-GO5, and IITKGP-20A-GO7 respectively), out of which IITKGP-20A-GO3 exhibits significantly high specific capacitance value (similar to 840 F g(-1) at 2 A g(-1)), which is one of the highest among the bare MOFs and their composites/derived materials. To verify its practical potentiality as positive electrode material, an asymmetric supercapacitor (ASC) device was fabricated displaying the specific capacitance of 111.4 F g(-1) at a current density of 2 A g(-1) while maintaining a high specific capacity of 65 F g(-1) even at a higher current density of 10 A g(-1). Moreover, the device produced 30.7 W h kg(-1) (0.031 W h cm(-3)) energy density with a very high power density of 388.5 W kg(-1) (0.394 W cm(-3)) with excellent retention of 84% cycle life up to 7000 cycles.

Automated summary

A highly capacitive two-dimensional nickel-metal organic framework was developed and combined with graphene oxide to create an effective supercapacitor device with high energy and power densities, and excellent cycle life retention.