Bipolar electrochemical capacitors using double-sided carbon nanotubes on graphite electrodes
Journal article, 2020

The electrochemical capacitor (EC) is a key enabler for the miniaturized self-powered systems expected to become ubiquitous with the advent of the internet-of-things (IoT). Vertically aligned carbon nanotubes (VACNTs) on graphite holds promise as electrodes for compact and low-loss ECs. However, as with all ECs, the operating voltage is low, and miniaturization of higher voltage devices necessitates a bipolar design. In this paper, we demonstrate a bipolar EC using graphite/VACNTs electrodes fabricated using a joule heating chemical vapor deposition (CVD) setup. The constructed EC contains one layer of double-sided VACNTs on graphite as bipolar electrode. Compared to a series connection of two individual devices, the bipolar EC has 22% boost in volumetric energy density. More significant boost is envisaged for stacking more bipolar electrode layers. The energy enhancement is achieved without aggravating self-discharge (71.2% retention after 1 h), and at no sacrifice of cycling stability (96.7% over 50000 cycles) owing to uniform growth of VACNTs and thus eliminating cell imbalance problems.

Miniaturized self-powered systems

Self-joule heating

Self-discharge

Series connection

Volumetric

CVD

Supercapacitor

Bipolar

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Published in

Journal of Power Sources

0378-7753 (ISSN)

Vol. 451 art. no 227765

Categorizing

Subject Categories (SSIF 2011)

Energy Engineering

Materials Chemistry

Other Electrical Engineering, Electronic Engineering, Information Engineering

Identifiers

DOI

10.1016/j.jpowsour.2020.227765

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Latest update

2/12/2020