Vertical Graphene Arrays as Electrodes for Ultra‐High Energy Density AC Line‐Filtering Capacitors. (12th October 2021)

• Record Type: Journal Article
• Authors: Xu, Shichen; Wen, Yeye; Chen, Zhuo; Ji, Nannan; Zou, Zhigang; Wu, Mingmao; Qu, Liangti; Zhang, Jin
• Is Part Of: Angewandte Chemie. Volume 133:Number 46(2021)
• Page Start: 24710
• Page End: 24714
• Publication Date: 2021-10-12
• Subjects: electric field -- filtering capacitor -- phase angle -- specific areal capacitance -- strictly vertical graphene arrays; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202111468
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: High‐frequency responsive electrochemical capacitor (EC), as an ideal lightweight filtering capacitor, can directly convert alternating current (AC) to direct current (DC). However, current electrodes are stuck in limited electrode area and tortuous ion transport. Herein, strictly vertical graphene arrays (SVGAs) prepared by electric‐field‐assisted plasma enhanced chemical vapour deposition have been successfully designed as the main electrode to ensure ions rapidly adsorb/desorb in richly available graphene surface. SVGAs exhibit an outstanding specific areal capacitance of 1.72 mF cm −2 at Φ 120 =80.6° even after 500 000 cycles, which is far better than that of most carbon‐related materials. Impressively, the output voltage could also be improved to 2.5 V when using organic electrolyte. An ultra‐high energy density of 0.33 μWh cm −2 can also be handily achieved. Moreover, ECs‐SVGAs can well smooth arbitrary AC waveforms into DC signals, exhibiting excellent filtering performance. Abstract : An electric‐field assisted PECVD method was developed to grow strictly vertical graphene arrays (SVGAs) as electrode materials of ECs. The EC‐SVGAs with aqueous or organic electrolyte exhibit excellent C A of 1.72 mF cm −2, Φ of 80.6°, and energy density of 0.33 μWh cm −2 at 120 Hz with arbitrary AC filtering performances, which is far better than most carbon‐related devices, demonstrating the potential for replacement of conventional AECs.