Bifunctional three-dimensional self-supporting multistage structure CC@MOF-74(NiO)@NiCo LDH electrode for supercapacitors and non-enzymatic glucose sensors

The bifunctional electrode materials for supercapacitors and non-enzymatic glucose sensors have attracted the researchers' great interest due to their excellent electrochemical performance. In this work, three-dimensional self-supporting multistage structure CC@MOF-74(NiO)@NiCo LDH electrode has been suc-cessfully prepared through a facile hydrothermal and electrochemical deposition method. Benefiting from the unique three-dimensional flower-like multistage structure, the optimized CC@MOF-74(NiO)@NiCo LDH electrode exhibits an excellent specific capacitance of 9.73 F cm(-2) and a superior rate capability of 77.65% at a high current density of 50 mA cm(-2). Besides, the material has a superior capacitance retention rate of 84.09% after 5000 cycles. Furthermore, the fabricated CC@MOF-74(NiO)@NiCo LDH//CC@NiCo2O4 @NiFe LDH ASC device exhibits a high energy density of 22.85 Wh kg(-1) and the power density of 1750 W kg(-1) at the current density of 10 mA cm(-2). Moreover, the as-prepared CC@MOF-74(NiO)@NiCo LDH shows an outstanding electrocatalytic performance in glucose detection, including a high sensitivity of 1699 mu A mM(-1) cm(-2), a low detection limit of 278 nM (S/N = 3) and a wide linear range of 10 mu M-1.1 mM and 1.5-9 mM. The electrode also has good long-term stability and remains 93.29% of the original current density after 35 days. The unique three-dimensional flower-like structure of MOF-74 and two-dimensional layered double hy-droxides (LDHs) nanosheets structure provide a larger specific surface area and improve the conductivity of the MOF-74(NiO). Furthermore, the synergistic effect of the bimetal Ni-Co provides more active sites for electrochemical reactions and shortens the ion transport path. Accordingly, the fabricated CC@MOF-74(NiO) @NiCo LDH has great potential application prospects in the field of supercapacitors and non-enzymatic glucose sensors. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study successfully prepared bifunctional electrode materials with a three-dimensional multistage structure, exhibiting excellent electrochemical performance and high energy density. The potential applications in supercapacitors and glucose sensors are promising.