Carbon nanofiber/poly(tetrahydro[1,4]dioxino[2,3-b]thieno[3,4-e][1,4]dioxine) binder-free composite redox-active electrode for electrochemical energy storage applications

Abstract

We report the preparation and supercapacitive properties of a novel composite electrode material based on carbon nanofiber (CNF) and poly(tetrahydro[1,4]dioxino[2,3-b]thieno[3,4-e][1,4]dioxine) (PTDTD) for electrochemical energy storage applications. The CNF/PTDTD composite electrode was directly prepared by electrodeposition of PTDTD on the CNF coated substrate without any binder or conductive additives. The symmetric solid-state supercapacitor device was assembled by using these CNF/PTDTD composite electrodes. In addition, CNF/CNF and CNF/poly(3,4-ethylenedioxythiophene) (PEDOT) symmetric supercapacitor devices were also fabricated to make a detailed performance comparison. The electrochemical characteristics of all supercapacitor devices were comprehensively evaluated by CV, GCD and EIS measurements. The CNF/PTDTD composite electrodes delivered a maximum specific capacitance of 332 F g⁻¹, energy density of 166 W h kg⁻¹, power density of 4.9 kW kg⁻¹ and an excellent cycling stability with 89% capacitance retention after 12 500 cycles at 2 mA cm⁻² current density while CNF/PEDOT electrodes were able to reach a specific capacitance of 254 F g⁻¹, energy density of 128.8 W h kg⁻¹ and power density of 5.45 kW kg⁻¹ in those supercapacitor devices. These results confirmed that PTDTD has significant potential to be a good alternative redox-active material and CNF/PTDTD composite structure is a promising candidate for supercapacitor applications.