Identification of self-discharge mechanisms of ionic liquid electrolyte based supercapacitor under high-temperature operation
Journal article, 2021

Ionic liquids (ILs) are promising electrolytes for supercapacitors (SCs) aimed for high-temperature applications, where increased ionic conductivity results in superior capacitive performance compared to room temperature (RT) performance. However, an increased temperature also accelerates the self-discharge rate that adversely affects energy retention and restricts the usage of SCs in standalone applications. In this study, a detailed electrochemical investigation on the self-discharge behaviour of carbon-based SCs containing an IL, 1-Ethyl-3-methylimidazolium acetate (EMIM Ac), has been carried out in the temperature range RT - 60 °C, and the underlying self-discharge mechanisms are identified. The results reveal that at a high voltage of 1.5 V, the self-discharge is characterized by a combination of charge redistribution and diffusion at both RT and 60 °C. At 60 °C, the diffusion-controlled mechanism dominates at lower voltages over the charge redistribution effect, while at RT both mechanisms contribute to a similar extent. The observed difference in the self-discharge mechanism between RT and 60 °C is explained in terms of a decreased RC time constant (τRC) at elevated temperature, and the same conclusions are potentially applicable to other IL-containing SCs as well.

Activated carbon

High temperature

Ionic liquid

Supercapacitor

Leakage current

Self-discharge

Author

Mohammad Mazharul Haque

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Qi Li

Wallenberg Wood Science Center (WWSC)

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Cristina Rigato

Chalmers, Electrical Engineering, Signal Processing and Biomedical Engineering, Biomedical Signals and Systems

Azega Rajendra Babu Kalai Arasi

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Wallenberg Wood Science Center (WWSC)

Anderson David Smith

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Per Lundgren

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Peter Enoksson

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Wallenberg Wood Science Center (WWSC)

Journal of Power Sources

0378-7753 (ISSN)

Vol. 485 229328

Miniaturized self-powered industrial sensor systems using energy harvesting technologies - Energy Supply Toolkit

VINNOVA, 2017-12-01 -- 2019-12-20.

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Energy

Materials Science

Subject Categories

Energy Engineering

Other Chemistry Topics

Energy Systems

Roots

Basic sciences

Infrastructure

Chalmers Materials Analysis Laboratory

Nanofabrication Laboratory

Learning and teaching

Pedagogical work

DOI

10.1016/j.jpowsour.2020.229328

More information

Latest update

2/19/2021