The Properties Of Sodium Ion Solid-electrolyte Supercapacitors

With the rapid development of the power supply industry,supercapacitors have emerged in the energy storage device market with their unique electrochemical performance.Supercapacitors have a larger capacity than ordinary capacitors and have a higher power density than ordinary batteries,filling the gap between traditional electrostatic capacitors and chemical power supplies.One of the difficulties in limiting the development of traditional supercapacitors is that their operating voltage is difficult to increase.In this paper,fast ion conductors are introduced for solid electrolytes,and carbon-based electrode materials are used to improve the capacitance performance of supercapacitors and reduce the internal resistance caused by solid electrolytes.This thesis mainly studies materials synthesis,device preparation,material characterization and electrochemical performance testing.The specific contents are as follows:?1?Using the high energy ball milling method,the main material of the experiment,???-Al₂O₃,was synthesized and analyzed by XRD,SEM and other means to determine the phase structure of the composite material is???-Al₂O₃.The grain size of the powder is 27 nm.Electrolyte samples Al/???-Al₂O₃/Al,Al/Na₂Ti₆O₁₃/Al and Al/Na₂Ti₆O₁₃+???-Al₂O₃/Al were prepared by tableting process.The results of electrochemical test showed that Na₂Ti₆O₁₃ and???-Al₂O₃ composite electrolyte The material has stable cycle performance and minimal charge and discharge charge loss for optimum performance.?2?A chip type supercapacitor was prepared by using carbon coated aluminum foil and semi-carbon aluminum foil as electrode materials.Electrochemical performance tests were carried out on the device.Correlation analysis and data comparison showed that the electrochemical properties of the carbon coated aluminum foil device were better and the specific capacitance was larger.The ratio of the electrolyte material Na₂Ti₆O₁₃ and???-Al₂O₃was studied.The best performance is obtained when the molar ratio of Na₂Ti₆O₁₃ to???-Al₂O₃ is 7:3,the specific capacitance is 44.75 mF/g,and the energy density is 0.945 Wh/kg.?3?On the basis of the Na-Al electrolyte material and the carbon-coated aluminum foil electrode material,the device preparation process was improved,and a wound supercapacitor sample was prepared.Compared with the original chip type supercapacitor,the thickness was reduced to 0.1 mm,and the electrode-electrolyte contact was made.More preferably,the internal resistance is reduced to 730?and the specific capacitance is increased to 133.69 mF/g.The test results show that the cycle stability is good,showing better capacitance performance and larger tantalum capacitance peak at low scan rate,and the energy density is 2.824 Wh/kg,and the power density is 10.17 kW/kg.?4?According to the impedance frequency test results,the internal working mechanism of the sodium ion supercapacitor is proposed by comparing and analyzing each sample.