Study On Preparation And Characterization Of Supercapacitor Three-dimensional Micro Electrode Array Based On MEMS Technology

The micro-supercapacitor is a new type of energy storage device with high energystorage density, high-power discharge, long cycle life, small size, charge speed, goodreliability, little pollution and so on, it is key components of information, electronics,instrumentation, energy, transportation, aerospace and National defense and security.Based on MEMS technology, the thesis focuses on solving key technical problems ofthe three-dimensional micro-supercapacitor electrode processing and its surfacefunctional film preparation, carried out supercapacitor three-dimensional microelectrodearray structure fabrication technology research, which possess important scientificsignificance and practical value.In this paper, we aiming at the urgent technology problem need to be solved formicro supercapacitor three dimensional micro electrode processing and surface functionfilm preparing, we proposed preparation of three-dimensional microelectrode arraystructure based on MEMS technology, and directly deposit the electrode activesubstance film on the three-dimensional microelectrode array structure surface by theelectrochemical method, then fabricated microelectrode array by this way. Analysisedthe relationship between morphology, spacing and the performance ofmicro-supercapacitor three-dimensional microelectrode array structure, and establishedthe electric field distribution model of three-dimensional micro-electrode array. Andstudied the design and preparation methods of SU–8photoresist and bulk siliconthree-dimensional microelectrode array structures. Galvanostatic, constant potential,pulse electrochemical deposition method were used to deposited manganese oxide,ruthenium oxide, polyaniline functional film as an electrode active substance on thesurface of the columnar, strip, comb, silicon based hole three-dimensionalmicro-electrode array structure. Three-dimensional micro-electrode array weresuccessfully prepared; Used scanning electron microscopy, cyclic voltammetry, constantcurrent charge-discharge method to characterize the electrodes character. Based on thefocused ion beam etching method, this paper studied the conductive film electrodeseparation technology, successfully separated the supercapacitor positive electrode andnegative electrode, researched and prepared the conductive polymer gel electrolyte,broke through the key techniques of supercapacitor electrode separation and packagebased on MEMS technology, and successfully fabricated a miniature super capacitor sample on the silicon. The main research works of this paper is listed as fellow:①Reviewed the status and development trends of the supercapacitormicroelectrode research, and analysised the existing shortcomings of the microelectrodepreparation method. The idea of the preparation micro-supercapacitor three-dimensionalmicroelectrode array based on MEMS technology was proposed.②Analysised the relationship between the micro supercapacitor three-dimensional microelectrode morphology, electrode distance and miniature supercapacitor performance, using finite element method analysis the distribution of theelectric field of the three-dimensional microelectrode array, the finite element model ofthe electric field of the three-dimensional micro-electrode array had been built, theinfluence of electric field of different electrode array morphology, size and distance hadbeen researched, the structure parameters of the three-dimensional microelectrode arrayhad been optimized.③Based on MEMS technology, we proposed design and processing method ofthree-dimensional micro-electrode array structure using the SU-8photoresist and siliconmaterial, and used electrochemical methods to deposit the active material film on thesurface of three-dimensional microelectrode array structure for prepare electrode.Studied the stress problem of SU-8photoresist micro-structure during the preparationprocess, and solved the key issues of binding force of the SU-8photoresistmicroelectrode array structure and the silicon substrate; Studied the preparation methodof the three-dimensional microelectrode array structure using silicon as the material andresolved the problem of “grass "and" black silicon" in the etching process.④Studied the preparation of electrode active material film in three-dimensionalmicroelectrode array structure surface, characterized surface morphology andelectrochemical properties of three-dimensional microelectrode array. Constant voltage,constant current method was used electro-deposition manganese oxide films, usingconstant voltage and cyclic voltammetry method to synthesize Polyaniline film,ruthenium oxide films had been prepared by dual-electrode square wave pulse. Theelectrode structure and the surface morphology and composition of the active materialfilm had been characterized by scanning electron microscopy, energy dispersivespectroscopy and X-ray diffraction. Electrochemical workstation was used to test themicroelectrode with cyclic voltammetry, AC impedance characteristics, constant currentcharge and discharge characteristics method, and completed the testing and analysis ofthe microelectrode. ⑤Researched the separation electrode technology using focused ion beam etching,successfully separated the positive and negative electrodes of the micro-supercapacitor.Studied and prepared the conductive polymer gel electrolyte, and solve the problem ofthe micro-supercapacitor electrode separation and supercapacitor package based onMEMS technology, and successfully prepared a micro-supercapacitor withthree-dimensional micro array electrode structure on a silicon substrate based on MEMS,specific capacity can reach33.05mF/cm2.