5 years ago

Decorating Graphene Oxide with Ionic Liquid Nanodroplets: An Approach Leading to Energy-Dense, High-Voltage Supercapacitors

Decorating Graphene Oxide with Ionic Liquid Nanodroplets: An Approach Leading to Energy-Dense, High-Voltage Supercapacitors
Michael A. Pope, Debasis Ghosh, Zimin She
A major stumbling block in the development of high energy density graphene-based supercapacitors has been maintaining high ion-accessible surface area combined with high electrode density. Herein, we develop an ionic liquid (IL)–surfactant microemulsion system that is found to facilitate the spontaneous adsorption of IL-filled micelles onto graphene oxide (GO). This adsorption distributes the IL over all available surface area and provides an aqueous formulation that can be slurry cast onto current collectors, leaving behind a dense nanocomposite film of GO/IL/surfactant. By removing the surfactant and reducing the GO through a low-temperature (360 °C) heat treatment, the IL plays a dual role of spacer and electrolyte. We study the effect of IL content and operating temperature on the performance, demonstrating a record high gravimetric capacitance (302 F/g at 1 A/g) for 80 wt % IL composites. At 60 wt % IL, combined high capacitance and bulk density (0.76 g/cm3), yields one of the highest volumetric capacitances (218 F/cm3, at 1 A/g) ever reported for a high-voltage IL-based supercapacitor. While achieving promising rate performance and cycle-life, the approach also eliminates the long and costly electrolyte imbibition step of cell assembly as the electrolyte is cast directly with the electrode material.

Publisher URL: http://dx.doi.org/10.1021/acsnano.7b04467

DOI: 10.1021/acsnano.7b04467

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.