Fast Energy Storage in Two-Dimensional MoO2 Enabled by Uniform Oriented Tunnels

Yuanyuan Zhu, Xu Ji, Shuang Cheng*, Zhao Ying Chern, Jin Jia, Lufeng Yang, Haowei Luo, Jiayuan Yu, Xinwen Peng, Jenghan Wang, Weijia Zhou, Meilin Liu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

While pseudocapacitive electrodes have potential to store more energy than electrical double-layer capacitive electrodes, their rate capability is often limited by the sluggish kinetics of the Faradaic reactions or poor electronic and ionic conductivity. Unlike most transition-metal oxides, MoO2 is a very promising material for fast energy storage, attributed to its unusually high electronic and ionic conductivity; the one-dimensional tunnel is ideally suited for fast ionic transport. Here we report our findings in preparation and characterization of ultrathin MoO2 sheets with oriented tunnels as a pseudocapacitive electrode for fast charge storage/release. A composite electrode consisting of MoO2 and 5 wt % GO demonstrates a capacity of 1097 C g-1 at 2 mV s-1 and 390 C g-1 at 1000 mV s-1 while maintaining ∼80% of the initial capacity after 10,000 cycles at 50 mV s-1, due to minimal change in structural features of the MoO2 during charge/discharge, except a small volume change (∼14%), as revealed from operando Raman spectroscopy, X-ray analyses, and density functional theory calculations. Further, the volume change during cycling is highly reversible, implying high structural stability and long cycling life.

Original languageEnglish
Pages (from-to)9091-9099
Number of pages9
JournalACS Nano
Volume13
Issue number8
DOIs
Publication statusPublished - 2019 Aug 27

Keywords

  • Density functional theory calculations
  • MoO
  • capacitor
  • energy storage
  • operando Raman

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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