High-frequency electrochemical capacitors based on plasma pyrolyzed bacterial cellulose aerogel for current ripple filtering and pulse energy storage

• Published in: Nano energy Vol. 40; pp. 107 - 114
• Main Authors: Islam, Nazifah, Li, Shiqi, Ren, Guofeng, Zu, Yujiao, Warzywoda, Juliusz, Wang, Shu, Fan, Zhaoyang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2017
• Subjects: AC filtering; Electrochemical capacitor; High-frequency supercapacitor; Kilohertz supercapacitor; Plasma pyrolysis; Pulse energy storage; Pulse energy storage; Plasma pyrolysis; High-frequency supercapacitor; Electrochemical capacitor; Kilohertz supercapacitor; AC filtering
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2017.08.015

There are great needs in developing compact-size kilohertz (kHz) high-frequency (HF) electrochemical capacitors (ECs) for ripple current filtering and environmental vibration energy harvesting. However, the previously demonstrated electrodes are generally limited to a very small areal capacitance density at 120Hz due to sub-μm thick electrode used for meeting frequency requirement, which renders them unsuitable for practical ECs. Here, using crosslinked carbon nanofiber aerogel, derived from rapid microwave plasma pyrolysis of bacterial cellulose that was synthesized in a fermentation process, we demonstrated kHz HF-ECs with areal capacitance density as high as 4.5mFcm−2 at 120Hz in an aqueous electrolyte. The cruciality of plasma pyrolysis on high frequency response of the derived carbon nanofiber aerogel was discussed. The electrode performance in an organic electrolyte was further studied for operation in a large potential window of more than 3V. Using such kHz HF-ECs, we further demonstrated their applications in rapid pulse energy storage for vibrational energy harvesting, as well as in ripple current filtering for AC/DC conversion. The promising results suggest this technology has great potential for developing practical compact HF-ECs in substitution of electrolytic capacitors for several crucial applications. Through microbe fermentation process, cellulose nanofiber aerogel was synthesized, which was converted to crosslinked carbon nanofiber aerogel in a rapid plasma pyrolysis process. Using such highly conductive carbon aerogel with large surface area and tailed porous structure, kilohertz high-frequency electrochemical capacitors (HF-EC) with large areal capacitance as high as 4.5mFcm−2 at 120Hz were demonstrated. HF-ECs operated at 3V were further demonstrated for pulse energy storage in environmental noise energy harvesting system for the first time. [Display omitted] •Through microbe fermentation process, cellulose nanofiber aerogel was synthesized.•Rapid plasma pyrolysis of cellulose aerogel into carbon nanofiber aerogel was investigated.•KHz high-frequency ECs with electrode capacitance as high as 4.5mFcm−2 at 120Hz.•KHz ECs operates at 3V were demonstrated.•KHz ECs for pulse energy storage in energy harvesting were demonstrated for the first time.