Compact and low loss electrochemical capacitors using a graphite / carbon nanotube hybrid material for miniaturized systems
Journal article, 2019
With the establishment of the internet of things (IoT) and the rapid development of advanced microsystems, there is a growing demand to develop electrochemical capacitors (ECs) to replace bulky electrolytic capacitors on circuit boards for AC line filtering, and as a storage unit in energy autonomous systems. For this purpose, ECs must be capable of handling sufficiently high signal frequencies, display minimum energy loss through self-discharge and leakage current as well as maintaining an adequate capacitance. Here, we demonstrate ECs based on mechanically flexible, covalently bonded graphite/vertically aligned carbon nanotubes (graphite/VACNTs) hybrid materials. The ECs employing a KOH electrolyte exhibit a phase angle of −84.8°, an areal capacitance of 1.38 mF cm−2 and a volumetric capacitance (device level) of 345 mF cm−3 at 120 Hz, which is among the highest values for carbon based high frequency ECs. Additionally, the performance as a storage EC for miniaturized systems is evaluated. We demonstrate capacitive charging/discharging at μA current with a gel electrolyte, and sub-μA leakage current reached within 50 s, and 100 nA level equilibrium leakage within 100 s at 2.0 V floating with an ionic liquid electrolyte.
Energy storage
Internet of things
AC line filter
Supercapacitors
Hybrid material
Author
Qi Li
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
S. Sun
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
Shanghai University
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Anderson David Smith
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
Per Lundgren
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
Yifeng Fu
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
Peng Su
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
Tao Xu
Southeast University
Lilei Ye
SHT Smart High-Tech
Litao Sun
Southeast University
Johan Liu
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
Shanghai University
Peter Enoksson
Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems
Journal of Power Sources
0378-7753 (ISSN)
Vol. 412 374-383Areas of Advance
Nanoscience and Nanotechnology
Subject Categories
Other Engineering and Technologies not elsewhere specified
Other Chemistry Topics
Other Electrical Engineering, Electronic Engineering, Information Engineering
DOI
10.1016/j.jpowsour.2018.11.052