Protein-assisted Synthesis Of Transition Metal Sulfides And Their Performance In Energy Storage

In the 21st century,human beings face many social problems:health problems,energy crisis,lack of resources,and environmental pollution.However,traditional techniques have been difficult to effectively solve the above problems.Therefore,the development of new technologies,new energy sources and novel energy storage devices have become one of the focus of people's attention.The supercapacitor is an energy storage and conversion system that is environment-friendly and has superior energy storage performance,which can effectively alleviate the problems facing humanity.Compared with other energy storage devices?batteries,conventional capacitors,etc.?,supercapacitors have advantages such as superior energy storage,long cycling lifetime,fast charge/discharge capability,and safe operation,and supercapacitors are widely used in electric vehicles,military equipment,and electronic equipment and other fields.Electrode materials are the core part of energy storage devices,and greatly influences the charge storage performance of the energy storage device.Searching for and exploration of high-performance electrode materials is a long-term pursuit of scientific researchers,and is the key to rapid development of energy storage devices in China.So far,electrode materials that have been widely studied and applied successfully in energy storage include carbon materials?carbon nanotubes,carbon nanofibers,etc.?,conductive polymers?polypyrrole,polythiophene,etc.?,and transition metal compounds?oxides,phosphides,etc.?.Among the above three types of materials,carbon-based materials are widely used in the electrode materials of electric double layer capacitors,but carbon-based materials are insufficient in energy storage?specific capacitance and specific energy?,which hinders their large-scale use in the field of energy storage.Conductive polymers?polypyrrole,polythiophene,etc.?and transition metal compounds?oxides,nitrides,etc.?differ from carbon-based materials.Conductive polymers?polypyrroles,etc.?and transition metal compounds?oxides,phosphides,etc.?are a typle of pseudocapacitors,which are mainly stored and released charge through redox reaction of the electrodes material.The performance in energy storage is significantly better than carbon-based materials.Conductive polymers are compared with sulfides,the repeated insertion and extraction of ions by the conductive polymer in the electrolyte solution,which will cause the expansion and contraction of the volume of the material,and therefore there is a deficiency in the cycle life of the conductive polymer material.Transition metals compounds?oxides,phosphides,etc.?are also havedisadvantageous,but have their own unique advantages in energy storage and cycle performance,and therefore transition metal compounds?oxides,phosphides,etc.?)are a class of high performance,promising energy storage materials that researchers are currently concerned about.In the transition metal compounds?oxides,phosphides,sulfides,etc.?,the composition of the metal sulfide varies,showing good conductivity,and the electrochemical performance is excellent in the energy storage device.There have been many reported methods for synthesizing metal sulfides,such as deposition methods and sol-gel methods and so on.Biomimetic method is a kind of synthesis technology which is synthesized in water system under room temperature conditions.It is an environment-friendly synthesis technology,and the synthesized material has the advantages of uniform morphology,easy control of crystal shape,excellent material properties,etc.So the biomimetic method is a new method for synthesizing nanomaterials with excellent properties.Here in,we are mainly to use protein-assisted hydrothermal synthesis of metal sulfides,and test the performance of the products.The main contents of this work are as follows:1 Protein-assisted hydrothermal synthesis of MoS₂ materials and electrochemical energy storage propertiesMoS₂ microsphere with the help of BSA was hydrothermally synthesized under the condition of 200°C and reaction time of 12 h,The influence of hydrothermal time and raw material ratio on the morphology of synthesized MoS₂ materials was explored,and the growth process of the product MoS₂ was discussed.The performance of the product MoS₂ was characterized by a three-electrode system.The test results show that,compared with other synthetic technologies,the material synthesized by this method has excellent performance,the capacitance value of 136.25 F/g?1 A/g?and a cycle life of up to 10,000.2 Protein-assisted hydrothermal synthesis of porous NiS₂ nanomaterials and electrochemical energy storage propertiesThe porous NiS₂ was synthesized by BSA assisted water thermal synthesis.The synthesized product was analyzed by series characterization.This material is porous nanosphere with small particles and the surface properties of the material are excellent.By doing different hydrothermal time experiments,the effect of NiS₂ on the morphology of its product was studied,and the best hydrothermal time was determined by the characterization results.The three-electrode system of the synthesized product was tested.The test results show that the porous NiS₂ is a type of pseudocapacitor material that exhibits excellent capacitance performance,the capacitance value of 1454 F/g at a current density of 1 A/g.The specific capacitance can also maintain a relatively high value of 738 F/g at a high current density of 10 A/g,indicating that the synthesized NiS₂ material has better energy storage performance.