Hybrid Graphene Ribbon/Carbon Electrodes for High‐Performance Energy Storage

Journal Article · 23 October 2018 · Advanced Energy Materials

DOI: https://doi.org/10.1002/aenm.201802439 · OSTI ID:1479524

Farquhar, Anna K.  ^[1]; Supur, Mustafa  ^[1]; Smith, Scott R.  ^[1]; Van Dyck, Colin  ^[2]; McCreery, Richard L.  ^[3]

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1. Department of Chemistry University of Alberta 11227 Saskatchewan Drive Edmonton Alberta T6G 2G2 Canada
2. Nanotechnology Research Centre National Research Council Canada 11421 Saskatchewan Drive Edmonton Alberta T6G 2M9 Canada
3. Department of Chemistry University of Alberta 11227 Saskatchewan Drive Edmonton Alberta T6G 2G2 Canada, Nanotechnology Research Centre National Research Council Canada 11421 Saskatchewan Drive Edmonton Alberta T6G 2M9 Canada

Abstract The utility of supercapacitors for both fixed and portable energy storage would be greatly enhanced if their energy density could be increased while maintaining their high power density, fast charging time, and low cost. This study describes a simple, solution‐phase, scalable modification of carbon materials by a covalently bonded “brush” of hydrogen‐terminated graphene ribbons (GRs) with layer thicknesses of 2–20 nm, resulting in a 20–100 times increase in the areal capacitance of the unmodified electrode surface. On a flat sp ² carbon surface modified by GRs, the capacitance exceeds 1200 µF cm ⁻² in 0.1 m H ₂ SO ₄ due to a distinct type of pseudocapacitance during constant current charge/discharge cycling. Modification of high surface area carbon black electrodes with GRs yields capacitances of 950–1890 F g ⁻¹ , power densities >40 W g ⁻¹ , and minimal change in capacitance during 1500 charge/discharge cycles at 20 A g ⁻¹ . A capacitance of 1890 F g ⁻¹ affords an energy density of 318 Wh kg ⁻¹ operating at 1.1 V and 590 Wh kg ⁻¹ at 1.5 V. The projected energy density of a hybrid GR/carbon supercapacitor greatly exceeds the current 10 Wh kg ⁻¹ for commercial supercapacitors and approaches that of lithium ion batteries.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐AC02‐06CH11357
• OSTI ID: 1479524
• Journal Information: Advanced Energy Materials, Journal Name: Advanced Energy Materials Vol. 8 Journal Issue: 35; ISSN 1614-6832
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English