Scalable fabrication of a flexible interdigital micro-supercapacitor device by in-situ polymerization of pyrrole into hybrid PVA-TEOS membrane

Phase-Inverted Copolymer Membrane for the Enhancement of Textile Supercapacitors

This paper presents a universal fabrication process for single-layer textile supercapacitors, independent of textile properties such as weave pattern, thickness and material. To achieve this, an engineered copolymer membrane was fabricated within these textiles with an automated screen printing, phase inversion and vacuum curing process. This membrane, together with the textile yarns, acts as a porous, flexible and mechanically durable separator. This process was applied to four textiles, including polyester, two polyester-cottons and silk. Carbon-based electrodes were subsequently deposited onto both sides of the textile to form the textile supercapacitors. These supercapacitors achieved a range of areal capacitances between 3.12 and 38.2 mF·cm⁻², with energy densities between 0.279 and 0.681 mWh·cm⁻³ with average power densities of between 0.334 and 0.32 W·cm⁻³. This novel membrane facilitates the use of thinner textiles for single-layered textile supercapacitors without significantly sacrificing electrochemical performance and will enable future high energy density textile energy storage, from supercapacitors to batteries.

Synthesis, Characterization and Electrochemical Performance of a Redox-Responsive Polybenzopyrrole@Nickel Oxide Nanocomposite for Robust and Efficient Faraday Energy Storage

A polybenzopyrrole@nickel oxide (Pbp@NiO) nanocomposite was synthesized by an oxidative chemical one-pot method and tested as an active material for hybrid electrodes in an electrochemical supercapattery device. The as-prepared composite material exhibits a desirable 3D cross-linked nanostructured morphology and a synergistic effect between the polymer and metal oxide, which improved both physical properties and electrochemical performance. The unprocessed material was characterized by X-ray diffraction, FTIR and UV-Vis spectroscopy, scanning electron microscopy/energy disperse X-ray analysis, and thermogravimetry. The nanocomposite material was deposited without a binder on gold current collectors and investigated for electrochemical behavior and performance in a symmetrical two- and three-electrode cell setup. A high specific capacity of up to 105 C g-1 was obtained for the Pbp@NiO-based electrodes with a gravimetric energy density of 17.5 Wh kg-1, a power density of 1925 W kg-1, and excellent stability over 10,000 cycles.

Designing flexible, smart and self-sustainable supercapacitors for portable/wearable electronics: from conductive polymers

The rapid development of portable/wearable electronics proposes new demands for energy storage devices, which are flexibility, smart functions and long-time outdoor operation. Supercapacitors (SCs) show great potential in portable/wearable applications, and the recently developed flexible, smart and self-sustainable supercapacitors greatly meet the above demands. In these supercapacitors, conductive polymers (CPs) are widely applied due to their high flexibility, conductivity, pseudo-capacitance, smart characteristics and moderate preparation conditions. Herein, we'd like to introduce the CP-based flexible, smart and self-sustainable supercapacitors for portable/wearable electronics. This review first summarizes the flexible SCs based on CPs and their composites with carbon materials and metal compounds. The smart supercapacitors, i.e., electrochromic, electrochemical actuated, stretchable, self-healing and stimuli-sensitive ones, are then presented. The self-sustainable SCs which integrate SC units with energy-harvesting units in one compact configuration are also introduced. The last section highlights some current challenges and future perspectives of this thriving field.

Physical, Chemical, and Electrochemical Properties of Redox-Responsive Polybenzopyrrole as Electrode Material for Faradaic Energy Storage

Polybenzopyrrole (Pbp) is an emerging candidate for electrochemical energy conversion and storage. There is a need to develop synthesis strategies for this class of polymers that can help improve its overall properties and make it as suitable for energy storage applications as other well-studied polymers in this substance class, such as polyaniline and polypyrrole. In this study, by synthesizing Pbp in surfactant-supported acidic medium, we were able to show that the physicochemical and electrochemical properties of Pbp-based electrodes are strongly influenced by the respective polymerization conditions. Through appropriate optimization of various reaction parameters, a significant enhancement of the thermal stability (up to 549.9 °C) and the electrochemical properties could be achieved. A maximum specific capacitance of 166.0 ± 2.0 F g⁻¹ with an excellent cycle stability of 87% after 5000 cycles at a current density of 1 A g⁻¹ was achieved. In addition, a particularly high-power density of 2.75 kW kg⁻¹ was obtained for this polybenzopyrrole, having a gravimetric energy density of 17 Wh kg⁻¹. The results show that polybenzopyrroles are suitable candidates to compete with other conducting polymers as electrode materials for next-generation Faradaic supercapacitors. In addition, the results of the current study can also be easily applied to other systems and used for adaptations or new syntheses of advanced hybrid/composite Pbp-based electrode materials.

Continuous and Patterned Conducting Polymer Coatings on Diverse Substrates: Rapid Fabrication by Oxidant-Intermediated Surface Polymerization and Application in Flexible Devices

Conducting polymer coatings and patterns are the most important forms of these materials for many practical applications, but a simple and efficient approach to these forms remains challenging. Herein, we report a universal oxidant-intermediated surface polymerization (OISP) for the fabrication of conducting polymer coatings and patterns on various substrates. A coating or pattern composed of densely packed colloidal V₂O₅·nH₂O nanowires is deposited on the substrate via spin coating, dip coating, or printing, which is converted into a conducting polymer one after in situ oxidation polymerization. The polymerization occurs selectively on the V₂O₅·nH₂O coatings, and high-quality polypyrrole, polyaniline, and poly(3,4-ethylenedioxythiophene) coatings and patterns on planar and curved polymeric, metallic, and ceramic substrates are obtained in a fast reaction rate similar to the electrochemical polymerization. The mechanistic study reveals that the method relies on the excellent processability and formability of V₂O₅·nH₂O nanowires, which is further explained by their large aspect ratio and surface activity. A flexible gas sensor array comprising three individual sensors made of different conducting polymers is fabricated using oxidant-intermediated surface polymerization, and it is successfully used to distinguish various analyte vapors. The method developed here will provide a powerful tool for the fabrication of conducting polymer-based devices.

Development of a novel SBA-15 templated mesoporous reduced graphitic oxide composite for high performance supercapacitors and fabrication of its device by an electrospinning technique

A novel synthetic route is formulated for the development of mesoporous reduced graphitic oxide (RGO)–silica composites by wrapping SBA-15 between the graphene oxide (GO) layers followed by a chemical reduction process.