| The world is experiencing an incessant consumption of fossil fuels and the gradual deterioration of the global environment,mankind has carried out extensive research on clean energy,and there is an urgent need to prepare a new type of energy storage device that can match it.Supercapacitors have received widespread attention due to their long cycle life,good cycle stability and high power density.However,with the development of electronic equipment in the direction of miniaturization and flexibility,traditional supercapacitors can no longer meet the needs of production and research and development.Miniature supercapacitors stand out because of their smaller size and better flexibility.Carbon materials are widely used as electrode materials for micro-supercapacitors due to their excellent chemical stability,abundant preparation technology and relatively low cost.In recent years,carbon-based micro-supercapacitors have made great progress,but low specific capacity and energy density are still outstanding problems.Aiming at this point,this paper chose to prepare a three-dimensional hierarchical porous carbon material and carried out process optimization and performance characterization.Using the optimized carbon material as the active material,the interdigital micro-supercapacitor was prepared by a simple and efficient mask-assisted squeegee method,and the performance of the micro-supercapacitor was characterized.The specific research content is as follows:（1）A kind of biomass from arid regions was selected as the precursor,and biomass-derived carbon materials（BDCs）were prepared by simple and efficient potassium hydroxide activation.The nitrogen adsorption and desorption characterization of biomass-derived carbon materials showed that with the increase of activation temperature,the pore volume of porous carbon increased from 0.547 cm3 g-1 to 1.123 cm3 g-1,and the specific surface area increased from 826m2 g-1 first increased to 2187.8 m2 g-1,and then decreased to 1945 m2 g-1.The specific surface area of BDC-700 was the largest,and BDC-800 formed a three-dimensional hierarchical pore structure dominated by micropores.X-ray diffraction and Raman spectroscopy were performed on the biomass-derived carbon materials,which proved that the prepared biomass-derived carbon materials have typical amorphous carbon structure characteristics.The electrochemical performance of the biomass-derived carbon material was characterized.In a three-electrode system,the specific capacity of BDC-700 can reach 529 F g-1 at 0.1 A g-1.The cyclic voltammetry curve of BDC-800 at 500 m V s-1 can still maintain an approximate rectangular shape,and the specific capacity can still reach 100 F g-1 at 100 A g-1,showed excellent rate performance.After 50000 charge-discharge cycles,the capacity retention rates of BDC-700and BDC-800 are 115.4%and 122.3%at 10 A g-1 and 50 A g-1,respectively.In the two-electrode system,the specific capacity of BDC-700 was 267 F g-1 at 0.1 A g-1;the current density increased from 0.5 A g-1 to 10 A g-1,the capacity rate of BDC-800 remained 65%.A long-cycle test was performed on BDC-800.The test results showed that the capacity retention rate of BDC-800 was 106.3%after 10000 charge-discharge cycles at a current density of 10 A g-1.（2）Using BDC-800 as the active material,the interdigital micro-supercapacitor was prepared by the mask-assisted coating method.The prepared micro-supercapacitors showed excellent integrity and flexibility.The electrochemical performance of the micro-supercapacitor was tested,and its specific capacity was 84.4 m F cm-2,76.1 m F cm-2,64.5 m F cm-2 and 53.7 m F cm-2 at 0.1 m A cm-2,0.2 m A cm-2,0.5 m A cm-2,and 1 m A cm-2.The capacity retention rate was 64.4%.After 1000 charge-discharge cycles at 1 m A cm-2,the capacity retention rate was 87%,showed good cycle stability.the power density was 50μW cm-2,the energy density was 11.72μWh cm-2,and when the power density was 500μW cm-2,the energy density was 7.41μWh cm-2.Serial and parallel micro-supercapacitor arrays are prepared by three micro-supercapacitors,and the series array had a voltage window of 3V,which proved excellent integration performance. |
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