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Published March 2, 2021 | Supplemental Material + Published
Journal Article Open

Significant Capacitance Enhancement via In Situ Exfoliation of Quasi-One-Dimensional Graphene Nanostripes in Supercapacitor Electrodes

Abstract

Graphene has received much attention as a supercapacitor electrode material due to its chemical inertness in preventing reaction with electrolytes and the large surface area due to its two-dimensional nature. However, when graphene sheets are processed into electrodes, they tend to stack together and form a turbostratic graphite material with a much reduced surface area relative to the total surface area of individual graphene sheets. Separately, electrochemical exfoliation of graphite is one method of producing single-layer graphene, which is often used to produce graphene for supercapacitor electrodes, although such exfoliated graphene still leads to reduced surface areas due to stacking during electrode fabrication. To utilize the large surface area of graphene, graphene must be exfoliated in situ within a supercapacitor device after the device fabrication. However, graphitic electrodes are typically destroyed upon exfoliation, which is largely due to the loss of electrical connectivity among small exfoliated graphene flakes. Here, we report successful in situ exfoliation of graphene nanostripes, a type of quasi-one-dimensional graphene nanomaterial with large length-to-width aspect ratios, as the anode material in supercapacitors. We find that the in situ exfoliation leads to over 400% enhancement in capacitance as the result of retaining the electrical connectivity among exfoliated quasi-one-dimensional graphene nanostripes in addition to increasing the total surface area, paving ways to fully realizing the benefit of graphene electrodes in supercapacitor applications.

Additional Information

© 2021 The Authors. Published by American Chemical Society. Made available through a Creative Commons CC-BY-NC-ND License. Received: December 16, 2020; Accepted: February 1, 2021; Published: February 18, 2021. The authors thank Professor George R. Rossman for allowing access to his Raman spectroscopy facilities, Professor Kimberly A. See for access to coin cell fabrication facilities, and the Beckman Institute at Caltech for access to XPS and electrochemical testing facilities. This research was jointly supported by the United Advanced Materials (Award #NCY.00012T15-1-GIFT.YEH0001T15) and the National Science Foundation under the Institute for Quantum Information and Matter (IQIM) at Caltech (Award #1733907). Author Contributions: J.D.B. designed the experiment; fabricated the GNSP materials; carried out Raman spectroscopy, XPS, XRD, and electrochemical measurements; and participated in preparing the manuscript. D.R.D. carried out GNSP dispersion and SEM imaging. N.-C.Y. coordinated and oversaw the research project and participated in preparing the manuscript. The authors declare no competing financial interest.

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Additional details

Created:
August 20, 2023
Modified:
October 23, 2023