The Influence Of Electrolyte Concentration On The Electrochemical Performance Of Cobalt-nickel-based Electrode Materials

Supercapacitor is a new type of energy storage devices,which has extremely wide applications in many fields.Electrolyte is an important part of supercapacitors.Their physical and chemical properties of electrolytes have an important impact on the electrochemical characteristics of supercapacitors.Researches on organic electrolytes,solid-state electrolytes and colloidal electrolytes are one of the hot topic.As traditional aqueous electrolytes,their basic researches still have important scientific significance and research value.As we all know,safe and high-efficiency are a primary concern for us when investigating electrolytes for supercapacitors.In recent years,scientists have studied the influence of KOH electrolyte concentrations on the electrochemical properties of carbon-based supercapacitors.However,the effects of KOH electrolyte concentrations on the electrochemical properties of transition metal oxide electrode materials are rarely reported.Which are more suitable concentrations of KOH electrolytes for transition metal oxide electrode materials?This question needs to be answered by the experimental researches.In this paper,thus,the effects of electrolyte concentrations on the electrochemical properties of NiO,Co₃O₄and NiCo₂O₄electrode materials in 1-5mol·L^-1KOH electrolytes were studied by an electrochemical workstation.The conclusions are as follows:1. The electrochemical properties of NiO,Co₃O₄and NiCo₂O₄electrode materials can be indeed controlled by adjusting KOH electrolyte concentrations within the range of 1-5 mol·L^-1.2. For the cubic NiO electrode materials,when KOH electrolyte concentration is 1 mol·L^-1,NiO electrode materials have the maximum output power density of 0.32k W·kg^-1and the minimum contact resistance of 0.381?.NiO electrode materials have the largest output energy density of 13.45 Wh·Kg^-1when being in 2 mol·L^-1,and the largest specific capacitance of 107.64 F·g^-1in 4 mol·L^-1.3. For the cubic Co₃O₄electrode materials,when KOH electrolyte concentration is 1 mol·L^-1,Co₃O₄electrode materials have the maximum output power density of 0.21k W·kg^-1and the minimum contact resistance of 0.375?.Co₃O₄electrode materials have the largest output energy density of 16.53 Wh·Kg^-1and the largest specific capacitance of 132.23 F·g^-1in 3 mol·L^-1.4. For the cubic NiCo₂O₄electrode materials,when KOH electrolyte concentration is 1 mol·L^-1,NiCo₂O₄electrode materials have the maximum output power density of0.69 k W·kg^-1.Moreover,NiCo₂O₄electrode materials have the minimum contact resistance of 0.382?in 2 mol·L^-1,the largest output energy density of 0.69 Wh·Kg^-1and the largest specific capacitance of 80.66 F·g^-1when being in 3 mol·L^-1.In conclusion,in this paper,we can control the concentrations of KOH electrolytes in the range of 1-5 mol·L^-1to achieve the best electrochemical properties of NiO,Co₃O₄and NiCo₂O₄electrode materials.