Compact and low loss electrochemical capacitors using a graphite / carbon nanotube hybrid material for miniaturized systems
Artikel i vetenskaplig tidskrift, 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.

Supercapacitors

AC line filter

Hybrid material

Energy storage

Internet of things

Författare

Qi Li

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

S. Sun

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Fingerprint Cards AB

Shanghai University

Anderson David Smith

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Per Lundgren

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Yifeng Fu

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Peng Su

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Tao Xu

Southeast University

Lilei Ye

SHT Smart High-Tech

Litao Sun

Southeast University

Johan Liu

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Shanghai University

Peter Enoksson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Journal of Power Sources

0378-7753 (ISSN)

374-383

Styrkeområden

Nanovetenskap och nanoteknik (2010-2017)

Ämneskategorier

Övrig annan teknik

Annan kemi

Annan elektroteknik och elektronik

DOI

10.1016/j.jpowsour.2018.11.052

Mer information

Senast uppdaterat

2019-02-26