Polyacrylate-graft-polypyrrole Copolymer as Intrinsically Elastic Electrodes for Stretchable Supercapacitors

"Bridge" interface design modulates high-performance cellulose-based integrated flexible supercapacitors

Flexible supercapacitors offer significant potential for powering next-generation flexible electronics. However, the mechanical and electrochemical stability of flexible supercapacitors under different flexibility conditions is limited by the weak bonding between neighboring layers, posing a major obstacle to their practical application. In this paper, natural coniferous pulp cellulose was successfully modified with ethylenediamine and NiSe2/Cell-NH2/MoS2 cellulose flexible electrodes (NCMF) were fabricated by phase transfer and hydrothermal methods. The amino-modified cellulose (Cell-NH2) acts as a "bridge" between NiSe2 and MoS2, significantly enhancing the interfacial bonding strength of the flexible electrode. The integrated flexible electrode exhibited a high area capacitance (2475 mF/cm2), strong tensile strength (10.3 MPa), and excellent cycling stability (92.1 % capacitance retention after 2500 cycles). The sandwich-structured monolithic supercapacitor achieved both a high electrode capacitance (56.78 F/cm2) and a high energy density (1971.53 μWh/cm2), while maintaining long cycling life (72.73 % capacitance retention after 2000 cycles) and large deformation capability. This makes it suitable for stable power supplies in electronic products and opens new possibilities for the flexible wearable industry. This technology enables stable power supplies for electronic products and paves the way for advancements in the flexible wearable industry.

Atomic-Level Insights of Polypyrrole Grafted InGaZnO Structure for ppb-Level Ozone Gas Sensing at Low Operating Temperature

This study explores the utilization of the organic conductive molecule Polypyrrole (PPy) for the modification of Indium Gallium Zinc Oxide (IGZO) nanoparticles, aiming to develop highly sensitive ozone sensors. Pyrrole (Py) molecules undergo polymerization, resulting in the formation of extended chains of PPy that graft onto the surface of IGZO nanoparticles. This interaction effectively diminishes oxygen vacancies on the IGZO surface, thereby promoting the crystallization of the IGZO (1114) facets. The resultant structure exhibits promising potential for achieving high-performance wideband semiconductor gas sensors. The IGZO/PPy device forms a Straddling Gap heterojunction, facilitating enhanced electron transfer between IGZO and ozone molecules. Notably, the adsorption and desorption of ozone gas occur efficiently at a low temperature of approximately 25 °C, obviating the need for additional energy typically associated with wide bandgap semiconductor materials. Density Functional Theory (DFT) calculations attribute this efficiency to the enhanced number of active sites for ozone adsorption, facilitated by hydrogen bonds. The substantial conductivity of PPy, combined with its planar ring structure, induces positively charged polarization on the IGZO side upon ozone adsorption. The resultant device exhibits exceptional sensitivity, boasting a 4-fold improvement compared to sensors reliant solely on IGZO. Additionally, the response time is significantly reduced by a factor of 10, underscoring the practical viability and enhanced performance of the IGZO/PPy sensor field.

Self-assembled high polypyrrole loading flexible paper-based electrodes for high-performance supercapacitors

Despite the intriguing features of freestanding flexible electronic devices, such as their binder-free nature and cost-effectiveness, the limited loading capacity of active material poses a challenge to achieving practical high-performance flexible electrodes. We propose a novel approach that integrates multiple self-assembly and in-situ polymerization techniques to fabricate a high-loading paper-based flexible electrode (MXene/Polypyrrole/Paper) with exceptional areal capacitance. The approach enables polypyrrole to form a porous conductive network structure on the surface of paper fiber through MXene grafting via hydrogen bonding and electrostatic interaction, resulting in an exceptionally high polypyrrole loading of 10.0 mg/cm2 and a conductivity of 2.03 S/cm. Moreover, MXene-modified polypyrrole paper exhibits a more homogeneous pore size distribution ranging from 5 to 50 μm and an increased specific surface area of 3.11 m2/g. Additionally, we have optimized in-situ polymerization cycles for paper-based supercapacitors, resulting in a remarkable areal capacitance of 2316 mF/cm2 (at 2 mA/cm2). The capacitance retention rate and conductivity rate maintain over 90 % after undergoing 100 bends.The maximum energy density and cycling stability are characterized to be 83.6 μWh/cm2 and up to 96 % retention after 10,000 cycles. These results significantly outperform those previously reported for paper-based counterparts. Overall, our work presents a facile and versatile strategy for assembling high-loading, paper-based flexible supercapacitors network architecture that can be employed in developing large-scale energy storage devices.