Preperation And Electrochemical Performance Of Symmetric/Asymmetric Supercapacitor Devices

Supercapacitors,which are becoming a new kind of efficient energy storage devices with excellent power density,superior cycle life and high security.With the increasing research of supercapacitors,there are large application prospects in new energy vehicles and wearable electronic devices and so on.Therefore,intensive studies are focused on option of electrode materials and optimization of electrolytes with respect to improve the energy density and other electrochemical properties of supercapacitor devices.In this paper,the main contents include:?1?Nitrogen-doped carbon microfibers were produced by carbonization of cattails seeds and subsequent KOH activation.These materials demonstrated good capacitive property with large capacitance of 214 F/g at the current density of 1 A/g.Then,based on this material,a symmetric supercapacitor device was assembled,which showed a considerable capacitance of 105 F/g at the current density of 1 A/g and perfect cycle stability which almost no decrease in capacitance after 10000 cycles.?2?Carbon doped TiO2?C-TiO2?nanotube arrays were prepared by anodization method and annealing at 450 ? in Ar.Then a all-solid-state flexible symmetric supercapacitor device was assembled by C-TiO2 and PVA-H3PO4 gel electrolyte.It should be noted that the specific capacitance had been improved as largely as five times,after the PB was involved in PVA-H3PO4 gel electrolyte.This method should be paid attention to supercapacitor for changing the disadvantage of its low energy density.?3?We assembled a novel asymmetric supercapacitor with VN@C as positive electrode and V₂O₃@C as negative electrode,PVA-Na₂SO₄ as the electrolyte,and the potential of this asymmetric supercapacitor device could reach 1.8 V.Its capacitance could reach 448 mF/cm² at the current density of 1 mA/cm²,and the energy density was as much as 0.2 mWh/cm².