Bipolar electrochemical capacitors using double-sided carbon nanotubes on graphite electrodes

JOURNAL OF POWER SOURCES

卷:451

Article

Hansson, Josef¹  Li, Qi¹  Smith, Anderson¹  Zakaria, Isaac²  Nilsson, Torbjorn¹  Nylander, Andreas¹  Ye, Lilei³  Lundgren, Per¹  Liu, Johan¹  Enoksson, Peter¹ 

[1] Chalmers Univ Technol, Dept Microtechnol & Nanosci MC2, Elect Mat & Syst Lab, S-41258 Gothenburg, Sweden

[2] Univ Calif Santa Barbara, Dept Chem Engn, Santa Barbara, CA 93106 USA

[3] SHT Smart High Tech AB, Kemivagen 6, S-41258 Gothenburg, Sweden

关键词: Self-joule heating;    CVD;    Supercapacitor;    Bipolar;    Series connection;    Volumetric;    Self-discharge;    Miniaturized self-powered systems;   

DOI  :  10.1016/j.jpowsour.2020.227765

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

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