Carbon fibre electrodes for ultra long cycle life pseudocapacitors by engineering the nano-structure of vertical graphene and manganese dioxides

Zhao Sha, Yang Zhou, Feng Huang, Wenmu Yang, Yuyan Yu, Jin Zhang, Shuying Wu, Sonya A. Brown, Shuhua Peng, Zhaojun Han, Chun H. Wang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Critical to the applications of pseudocapacitors is the cycling performance of electrodes. Here, we present a new carbon fibre electrode enhanced by multilayer structure of vertical graphene (VG) and manganese dioxide (MnO2) to achieve a cycling performance at a very high areal capacitance (546.3 mF/cm2) that outperforms most of the reported pseudocapacitors in the literature. Particularly, this multilayer electrode is able to retain 99.3% of its initial capacitance after 10,000 cycles at scan rate of 200 mV/s. The retention ratio is significantly higher than the state-of-art value. In addition, this electrode shows excellent rate performance (75.4% capacitance retention for current density from 1 to 10 mA/cm2). This exceptionally high stability at high capacitance and rate performance originates from the multilayer electrode's effectiveness in self-replenishing the degraded MnO2 in the outer layer. The microcracks and micro holes induced in the VG layer by electrical charge/discharge cycling enable the inner layer MnO2 to progressively participate in the redox reaction. Results from energy dispersive spectroscopy, X-ray photoelectron, and Raman spectroscopy confirm the self-replenishing mechanism responsible for the exceptionally stable performance. The new multilayer electrode designed herein provides a new route for improving the cycling performance of pseudocapacitors.

Original languageEnglish
Pages (from-to)260-270
Number of pages11
JournalCarbon
Volume177
DOIs
Publication statusPublished - 15 Jun 2021

Keywords

  • Multilayer electrode
  • Vertical graphene
  • Manganese dioxide
  • Cycling performance
  • Pseudocapacitor

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