MnOx embedded in 3D foam-like polymers composite for high-performance flexible supercapacitors

Abstract

High-performance flexible supercapacitors (SCs) strongly require a scaffold with a large specific surface area, high conductivity, and exceptional flexibility. The in situ growth of current collectors and/or active materials on 3D self-supported scaffolds not only simplifies the fabrication process but also enhances the electrode capacity. In this work, a novel manganes dioxide (MnOx) embedded 3D foam-like PEUS matrix composite electrode (PEUS-Mn-PS) with good conductivity and flexibility was prepared with a simple and facile method, where PEUS matrix containing of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and water polyurethane (PU) were fabricated using poly(3,4-ethylenedioxythiophene) (PEDOT) decorated Ni foam (NF) as the sacrificial template. In the electrode, PEUS functioned as a flexible conductive scarfolld, providing excellent mechanical properties and a large specific surface area for MnOx electrodeposition. Specify, with the surface modification of NF using a thin layer of PEDOT, the synthesized porous PEU matrix exhibited a more regular 3D interconnected scaffold resembling that of NF. The resulting flexible PEUS-Mn-PS electrode exhibited an exceptional areal specific capacitance of 681.7 mF/cm2 (~486.9 F/g) at 1 mF/cm2, much larger than 358.9 mF/cm2 of the PUS-Mn-PS electrode prepared without PEDOT modification and 318.7 mF/cm2 of the NF-Mn electrode synthesized through direct electrodeposition of MnOx on NF. The resulting PEUS-Mn-PS electrode allowed the assembled solid-state symmetric flexible SC to achieve an impressive energy density of 0.043 mWh/cm2 at a power density of 2.24 mW/cm2, while maintaining excellent electrochemical performance even under various bending angles. This work provides a new approach to designing high-performance flexible SC electrode materials using a simple, cost-effective, and environmentally friendly method.