Preparation And Electrochemical Properties Of Bifunctional Three-dimensional Hierarchical Transition Metal Electrodes

With the increasing demand for more efficient,green and clean energy,electrode materials of supercapacitor with satisfactory specific capacitance,high power density and good cycle stability are considered as promising energy storage materials.However,the research based on single functional electrode materials is not enough to meet the dual or multi-functional electrochemical requirements.Therefore,a stretchable supercapacitor energy storage device and a biosensor device have been integrated into an electrochemical device,which facilitates the generation of multifunctional materials.In this paper,based on the micro morphology and electrochemical properties of electrode materials,two kinds of bifunctional electrode materials have been designed,which show good capacitance and electrocatalytic performance in the applications of supercapacitor and non-enzyme glucose sensor.In this study,the carbon cloth(CC)with good electron transport capacity was selected as the collector and two kinds of electrode materials with unique three-dimensional structure were constructed by adjusting the reaction route,time and temperature reasonably.The active substance was grown in situ on the conductive carbon cloth without any binder and conductive polymer,which maintains the electrochemical active area of the material and provides more effective active sites for the electrochemical reaction.At the same time,the synergistic effect of transition metal oxides and bimetallic hydroxides improves the capacitive and electrocatalytic properties of the materials.Specific research contents are as follows:(1)Firstly,3D flower CC@MOF-74(Ni)was grown in situ on 1D carbon fiber by hydrothermal method,which was successfully transformed into CC@MOF-74(Ni O)after annealing treatment.Secondly,2D Ni Co LDH nanosheets were grown on the CC@MOF-74(Ni O)by simple electrodeposition method.Then,the 3D multistage CC@MOF-74(Ni O)@Ni Co LDH composite electrode material was successfully fabricated.The electrode material 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 m A cm^-2.Besides,the material has a superior capacitance retention rate of 84.09%after 5000 cycles.In addition,the linear range of glucose detection is 10?m?1.1 m M and 1.5?9 m M,the sensitivity is 1699?A m M^-1 cm^-2 and the detection limit is 278 nM.The fabricated CC@MOF-74(Ni O)@Ni Co LDH is a kind of bifunctional electrode material with excellent performance.(2)The typical spinel oxide Ni Co₂O₄ was grown on the CC as the“core material”by hydrothermal and heat treatment.Then,the 2D Ni Mn LDH nanosheets with high specific capacity was successfully prepared by hydrothermal method as the"shell material".The 3D core-shell CC@Ni Co₂O₄@Ni Mn LDH composite electrode material shows a specific capacitance of 3.044 F cm^-2 at the current density of 1 m A cm^-2 and a high capacitance retention rate of 92.05%after 5000 cycles.In addition,the linear range of glucose is 5?m?3 m M and 4?8 m M,the sensitivity is up to 2139?A m M^-1 cm^-2 and the detection limit is 210 nM.The synthesized CC@Ni Co₂O₄@Ni Mn LDH electrode material exhibits high specific capacitance,good cycle stability,wide detection range and excellent anti-interference performance in electrochemical testing.