Abstract:Horizontally directed nanofibrillar PEDOT mats bearing high impact energy densities are fabricated as electrodes for impact-resistant flexible supercapacitors.
“…We readily control the polymerization mechanism as an acid-catalyzed polymerization typically produces nonconductive oligomers stemming from active chain termination 16 . Only PEDOT synthesized via oxidative radical polymerization exhibits long conjugation length, ordered chain packing, low electrical resistance, as well as high chemical and physical stability 13 , 14 , 17 , 18 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…A blue PEDOT coating is visible on a brick 4 h after initiating a reaction and its thickness increases inversely proportional with electrical resistance until the end of reaction at 14 h. An extended polymerization time increases the polymer coating's two-point probe electrical resistance ( Supplementary Fig. 2d) because PEDOT loses dopant during heating 18 ; fortunately, post-synthetic doping lowers the electrical resistance. Our synthesis produces a 400 µm thick nanofibrillar PEDOT coating (2.8 wt%) exhibiting 2Ω two-point probe electrical resistance and nanofibers characterized by a~30 µm length and 190 nm diameter ( Supplementary Fig.…”
Section: Conversion Of a Fired Brick's α-Fe 2 O 3 To A Pedot Coatingmentioning
Fired brick is a universal building material, produced by thousand-year-old technology, that throughout history has seldom served any other purpose. Here, we develop a scalable, costeffective and versatile chemical synthesis using a fired brick to control oxidative radical polymerization and deposition of a nanofibrillar coating of the conducting polymer poly(3,4ethylenedioxythiophene) (PEDOT). A fired brick's open microstructure, mechanical robustness and~8 wt% α-Fe 2 O 3 content afford an ideal substrate for developing electrochemical PEDOT electrodes and stationary supercapacitors that readily stack into modules. Fiveminute epoxy serves as a waterproof case enabling the operation of our supercapacitors while submerged underwater and a gel electrolyte extends cycling stability to 10,000 cycles with~90% capacitance retention.
“…We readily control the polymerization mechanism as an acid-catalyzed polymerization typically produces nonconductive oligomers stemming from active chain termination 16 . Only PEDOT synthesized via oxidative radical polymerization exhibits long conjugation length, ordered chain packing, low electrical resistance, as well as high chemical and physical stability 13 , 14 , 17 , 18 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…A blue PEDOT coating is visible on a brick 4 h after initiating a reaction and its thickness increases inversely proportional with electrical resistance until the end of reaction at 14 h. An extended polymerization time increases the polymer coating's two-point probe electrical resistance ( Supplementary Fig. 2d) because PEDOT loses dopant during heating 18 ; fortunately, post-synthetic doping lowers the electrical resistance. Our synthesis produces a 400 µm thick nanofibrillar PEDOT coating (2.8 wt%) exhibiting 2Ω two-point probe electrical resistance and nanofibers characterized by a~30 µm length and 190 nm diameter ( Supplementary Fig.…”
Section: Conversion Of a Fired Brick's α-Fe 2 O 3 To A Pedot Coatingmentioning
Fired brick is a universal building material, produced by thousand-year-old technology, that throughout history has seldom served any other purpose. Here, we develop a scalable, costeffective and versatile chemical synthesis using a fired brick to control oxidative radical polymerization and deposition of a nanofibrillar coating of the conducting polymer poly(3,4ethylenedioxythiophene) (PEDOT). A fired brick's open microstructure, mechanical robustness and~8 wt% α-Fe 2 O 3 content afford an ideal substrate for developing electrochemical PEDOT electrodes and stationary supercapacitors that readily stack into modules. Fiveminute epoxy serves as a waterproof case enabling the operation of our supercapacitors while submerged underwater and a gel electrolyte extends cycling stability to 10,000 cycles with~90% capacitance retention.
“…Coating a flexible substrate requires (1) an oxidizing FeCl 3 solution or (2) a solid-state powder of α-Fe 2 O 3 particles; the former is applied via drop-casting and the latter by impregnation (Figure ). When a FeCl 3 solution is utilized, ferric ion serves as initiator, oxidant, and dopant polymerizing the EDOT monomer from 50 to 150 °C (Figure b). − ,, This synthetic approach requires a dilute FeCl 3 solution (10 –1 M) to control hydrolysis, thereby resulting in a low PEDOT mass loading (∼0.5 mg/cm 2 ); maximum mass loading reported in the literature (∼2 mg/cm 2 ) is achieved using a saturated FeCl 3 solution. ,,,, …”
Section: Resultsmentioning
confidence: 99%
“…The difference in decomposition temperature between PEDOT and carbon cloth enables quantitative determination of PEDOT mass loading via thermogravimetric analysis (Figure b). Dopant loss commences at 120 °C, and the polymer completely decomposes at 500 °C in air, while carbon cloth remains stable up to 600 °C. , The isotherm at 500 °C (1 h) provides complete subtraction of polymer mass for electrode mass loading calculation (Figure S3, Supporting Information). The α-Fe 2 O 3 -derived PEDOT on carbon cloth shows a ∼70 wt % PEDOT content (mass of polymer and dopant/overall electrode mass) and a mass loading of 30.2 mg/cm 2 (mass of polymer and dopant/electrode area), significantly higher than the ∼15 wt % and 2.1 mg/cm 2 from the FeCl 3 -derived PEDOT.…”
Section: Resultsmentioning
confidence: 99%
“…Typically, when synthesizing a conducting polymer from the vapor phase, an oxidative radical polymerization is engineered using monomer vapor and a solid substrate. The chemical synthesis of PEDOT is controlled by preapplying a coating of an aqueous oxidizing solution of FeCl 3 to a substrate and utilizing vapor of the monomer 3,4-ethylenedioxythiophene (EDOT). − Previous findings in our laboratory demonstrate that hydrolysis of Fe 3+ during vapor synthesis produces FeOOH nanospindles that template the growth of PEDOT nanofibers. ,, Hydrolysis, as our work demonstrates, is an ideal route for utilizing iron oxides, oxyhydroxides, and hydroxides (commonly found in iron rust) as reactants for synthesis . In this work we show that α-Fe 2 O 3 particles serve as a ubiquitous and cost-effective oxidant precursor that impregnates a flexible carbon cloth substrate and leads to a flexible nanofibrillar PEDOT thick electrode.…”
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).
Considerable progress in materials development and device integration for mechanically bendable and stretchable optoelectronics will broaden the application of “Internet‐of‐Things” concepts to a myriad of new applications. When addressing the needs associated with the human body, such as the detection of mechanical functions, monitoring of health parameters, and integration with human tissues, optoelectronic devices, interconnects/circuits enabling their functions, and the core passive components from which the whole system is built must sustain different degrees of mechanical stresses. Herein, the basic characteristics and performance of several of these devices are reported, particularly focusing on the conducting element constituting them. Among these devices, strain sensors of different types, energy storage elements, and power/energy storage and generators are included. Specifically, the advances during the past 3 years are reported, wherein mechanically flexible conducting elements are fabricated from (0D, 1D, and 2D) conducting nanomaterials from metals (e.g., Au nanoparticles, Ag flakes, Cu nanowires), carbon nanotubes/nanofibers, 2D conductors (e.g., graphene, MoS2), metal oxides (e.g., Zn nanorods), and conducting polymers (e.g., poly(3,4‐ethylenedioxythiophene):poly(4‐styrene sulfonate), polyaniline) in combination with passive fibrotic and elastomeric materials enabling, after integration, the so‐called electronic skins and electronic textiles.
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