Significantly Enhanced Electrochemical Performance of 2d Ni-Mof by Carbon Quantum Dot For High-Performance Supercapacitors

Abstract

Rational design of metal-organic framework (MOF) materials with rich active sites and high conductivity is very important for their applications in the energy storage devices, but it is still a great challenge. Herein, carbon quantum dot (CQD)/NiMOF composites are synthesized via a one-pot hydrothermal method. The experimental results show that CQDs can effectively enhance the electrical conductivity of NiMOF and regulate its morphology to expose abundant active sites. The as-prepared CQD@MOF composite delivers a specific capacitance of 1081.5 C g -1 at 1 A g -1 , and the outstanding cycling stability of 84.5% retention after 5000 charge/discharge cycles. Moreover, the hybrid supercapacitors with activated carbon (AC) as the negative electrode and CQD@MOF as the positive electrode exhibits a wide voltage window of 1.6 V and a high energy density of 56.3 Wh kg -1 at a power density of 4.3 kW kg -1 . The results can effectively boost the electrochemical performance of MOF and promote its application in supercapacitor electrode materials.

Keywords: Supercapacitors, MOF, Binder-free, CQD, Hybrid supercapacitor