Solid-State Precursor Impregnation for Enhanced Capacitance in Hierarchical Flexible Poly(3,4-Ethylenedioxythiophene) Supercapacitors

Abstract

Increasing capacitance and energy density is a major challenge in developing supercapacitors for flexible portable electronics. A thick electrode with a high mass loading of active electronic material leads to high areal capacitance; however, the higher the loading, the higher the mechanical stiffness and ion diffusion resistance, thereby hampering development of flexible supercapacitors. Here, we show a chemical strategy that leads to a hierarchical electrode structure producing devices with both an exceedingly high areal capacitance and superior flexibility. We utilize α-Fe2O3 particles as an oxidant precursor for controlling oxidative radical polymerization of the conducting polymer poly­(3,4-ethylenedioxythiophene) (PEDOT) from the vapor phase. Our approach impregnates carbon cloth with α-Fe2O3 particles prior to monomer vapor exposure, resulting in state-of-the-art flexible nanofibrillar PEDOT supercapacitors possessing high areal capacitance (2243 mF/cm2 for two-electrode vs 6210 mF/cm2 for three-electrode) and high areal energy density (412 μWh/cm2).

A Review on the Conventional Capacitors, Supercapacitors, and Emerging Hybrid Ion Capacitors: Past, Present, and Future

“…For example, Wang et al prepared the nanofibrillar polymer poly(3,4‐ethylenedioxythiophene) (PEDOT) with a high mass loading of 30.2 mg cm −2 by employing the α‐Fe 2 O 3 particles as an oxidant precursor. [ 77 ] The as‐obtained flexible PEDOT electrode performed a gravimetric capacitance of 206 F g −1 , an areal capacitance of 6210 mF cm −2 , and a volumetric capacitance of 138 F cm −3 at 2 mV s −1 . The PEDOT symmetric supercapacitor behaved an areal capacitance of 2243 mF cm −2 and an energy density of 312 μWh cm −2 .…”

Scalable Paper Supercapacitors for Printed Wearable Electronics

“…29−31 In energy storage applications, PEDOT can be used as a capacitive coating material for Libattery cathodes and as high-capacity electrode material for supercapacitors, where the material can be produced with both physical deposition techniques and polymerization methods such as oxidative chemical vapor deposition (oCVD) and electropolymerization. 31,32 PEDOT can also be polymerized into the paper-based systems, 33,34 but since such paper electrodes are integrated into supercapacitor structures with lamination, the devices will exhibit high equivalent series resistance (ESR), limited bending stability, and bending radius. Further, the fabrication methods limit the produced area and the mechanical robustness.…”

Heterostructure Fe2O3 nanorods@imine-based covalent organic framework for long cycling and high-rate lithium storage

“…To address this issue, tremendous efforts have been conducted to improve the long-term cycling performance and rate capability of Fe 2 O 3 , such as morphology tuning by nano-modification to increase the SSA with more storage sites and a shortened diffusion distance. 12–17 Besides, compound engineering and elemental doping ( e.g. , Ti/Co/Mn/Zn/Ni, etc .…”