Engineering the interface for promoting ionic/electronic transmission of organic flexible supercapacitors with high volumetric energy density

Abstract

Supercapacitors based on commercialized metallic collectors (such as Cu and Al) possess an innate interface imperfection, causing long ion diffusion pathway and sluggish electron conduction, as well as inferior flexibility. Herein, we explore carbon nanotubes macroscopic films (CMF) as current collectors to build near-integrated electrodes via anchored combination between CMF and commercial active carbon (AC). In addition, our fabricated CMF presents outstanding electrolyte permeation, which shortens the ion diffusion pathway, increases the electron conduction and ameliorates the flexibility. As a result, the supercapacitor based on CMF exhibits prominent electrochemical performance of specific capacitance (48.5 F cm−3 at 0.5 A g−1), rate capability (82.5% from 0.5 to 16 A g−1) and volumetric energy density (104.9 Wh L−1), which higher than those of reported flexible supercapacitors. More importantly, the supercapacitor exhibits remarkable stability under different folding conditions, even in particular circumstances (such as low temperature and negative pressure). Further, the supercapacitors show good energy features in parallels and series. Therefore, it is believed that these supercapacitors based on CMF are promising in the future wearable energy storage devices in different operating environments.