Probing the effect of solvents on the electrochemical performance of graphene incorporated nickel-based metal organic frameworks

Abstract

• The electrochemical performance of Ni-MOFs synthesized in different solvent systems were studied. • Binary solvent system with high polarity and viscosity was favorable for the formation of small-sized nanosheets. • The electrochemical performance was significantly enhanced by incorporating graphene. • The capacitance retention was recorded at 97.70% after 10,000 cycles. Highly porous coordinated metal-organic frameworks (MOFs) have attracted enormous interest by virtue of their promising electrochemical performance in the application of energy storage systems. In this study, the associated electrochemical performance of nickel-based MOFs ([Ni 3 (OH) 2 (C 8 H 4 O 4 ) 2 (H 2 O) 4 ]·2H 2 O, Ni-MOFs) synthesized in different solvent systems was systematically investigated. It is found that binary solvents with high polarity and viscosity were favorable for the formation of small-sized nanosheets. Meanwhile, graphene was incorporated into Ni-MOFs to further enhance the electrochemical performance of the nanocomposite via a facile one-pot solvothermal approach. By taking advantage of the synergistic effect between highly conductive graphene nanosheets and hierarchical Ni-MOFs, the as-synthesized Ni-MOF/graphene nanocomposites exhibited excellent electrochemical performance with significant reduction of charge transfer resistance. The delivered maximum energy and power density of the nanocomposite were 14.68 Wh kg −1 and 2,852 W kg −1 , respectively. Furthermore, a remarkable capacitance retention of 97.70 % over 10,000 cycles was achieved by the nanocomposite electrode, indicating its potential to be applied in high-performance and long cycle-life energy storage devices.