Specializing liquid electrolytes and carbon-based materials in EDLCs for low-temperature applications

Electric double-layer capacitors (EDLCs) are emerging technologies to meet the ever-increasing demand for sustainable energy storage devices and systems in the 21st Century owing to their advantages such as long lifetime, fast charging speed and environmentally-friendly nature, which play a critical part in sat-isfying the demand of electronic devices and systems. Although it is generally accepted that EDLCs are suitable for working at low temperatures down to-40 degrees C, there is a lack of comprehensive review to summarize the quantified performance of EDLCs when they are subjected to low-temperature environ-ments. The rapid and growing demand for high-performance EDLCs for auxiliary power systems in the aeronautic and aerospace industries has triggered the urge to extend their operating temperature range, especially at temperatures below-40 degrees C. This article presents an overview of EDLC's performance and their challenges at extremely low temperatures including the capability of storing a considerable amount of electrical energy and maintaining long-term stability. The selection of electrolytes and electrode mate-rials is crucial to the performance of EDLCs operating at a desired low-temperature range. Strategies to improve EDLC's performance at extremely low temperatures are discussed, followed by the future per-spectives to motivate more future studies to be conducted in this area.(c) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.