Preparation Of Fabric-based Three-dimensional Micro-supercapacitors And Their Energy Storage Performance

With the rapid development of the electronic industry,the energy storage equipment that matches it is also moving forward.Micro supercapacitors are a class of supercapacitors with smaller specifications,which are valued for their small specifications,fast charging and discharging speed,high power density,long cycle life and environmental protection.On the one hand,it is necessary to improve the conductivity,rheology and printability of conductive ink to meet the high resolution and strong electrochemical characteristics of the printed pattern;on the other hand,construct a three-dimensional array structure on the surface of two-dimensional substrate to improve the loading and capacitance of micro supercapacitors with limited area.On the other hand,it is necessary to construct three-dimensional array structures on the surface of two-dimensional substrates to improve the loading and capacitive activity of electrode materials within the limited area of micro supercapacitors.In this paper,we use screen printing and high-voltage electrostatic implantation techniques to implant multi-stage aperture carbon fibers onto a conductive substrate with a forked finger structure,and combine with electrodeposition techniques to load pseudocapacitive electrode materials and construct high performance fabric-based three-dimensional micro supercapacitors.The details of the study are as follows.(1)Preparation and performance testing of fabric-based two-dimensional micro-supercapacitors.The water-based conductive ink was prepared with acidified carbon nanotubes as the conductive filler,hydroxyethyl cellulose as the binder,and deionized water and isopropanol as the solvent.85.17?,the prepared conductive ink has a lower resistance and suitable rheological and printing adaptability.The composite conductive ink was prepared by adding Mn O₂ at 0.347 g under the optimal preparation process conditions,and the forked finger structure conductive fabric electrode(CO-CNT-Mn O₂)was prepared by screen printing technique.The two-dimensional micro-supercapacitor assembly was further combined with the gel electrolyte PVA/Li Cl,in which the optimized CO-CNT-Mn O₂-based two-dimensional micro-supercapacitor had an area specific capacitance of 3.732 m F/cm²and an energy density of 1.866 m Wh/cm² at a scan rate of 100 m V/s,with an energy density of 3.8%higher than that of Mn O₂ before.(2)Preparation and performance analysis of fabric-based three-dimensional micro-supercapacitors based on high-voltage implantation technology.By combining the porogenic mechanism of carbon fibers and optimizing the amount of its activator,it was determined that the prepared activated carbon fibers had microporous and mesoporous structures with an average pore size of 2.224 nm,when M_{carbon fiber}:M_KOH of 1:2polyacrylamide was further used as a dispersant,combined with mechanical vibration to disperse the activated carbon fibers effectively.The activated and dispersed carbon fibers were implanted onto the fabric-based two-dimensional forked-finger structure conductive substrate(CO-CNT)in a high-voltage electrostatic field,and the effects of flocking voltage,flocking time and pole plate spacing on the flocking density were explored and optimized by combining with orthogonal tests,and it was concluded that the carbon fiber array structure was more regular and the implantation density was more uniform when the flocking voltage was 25 k V,the flocking time was 5 s and the pole plate spacing was 10 cm.The three-dimensional fabric-based micro-supercapacitor assembly using gel electrolyte PVA/Li Cl has an area specific capacitance of 5.516 m F/cm²at a scan rate of 100 m V/s,which is 53.4%higher than that of the two-dimensional micro-supercapacitor,and its energy density is 2.758 m Wh/cm².(3)Preparation of CO-CNT-F@Mn Co with Mn-Co-based oxide loading and energy storage performance.The fabric-based three-dimensional micro-supercapacitor(CO-CNT-F@Mn Co)assembly was carried out by loading Mn-Co-based oxide onto a three-dimensional fork-finger structured conductive substrate using electrochemical deposition technique in combination with gel electrolyte PVA/Li Cl.By optimizing the number of deposition turns,deposition voltage and scan rate under cyclic voltammetric deposition conditions,the area specific capacitance of CO-CNT-F@Mn Co after depositing Mn-Co oxide was increased by 18.9%compared with that before deposition,and the energy density reached 3.281 m Wh/cm².It has a wide application prospect in wearable electronic devices because of its flexibility,high energy density and good electrochemical cycle stability.