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 21 st Century owing to their advantages such as long lifetime, fast charging speed and environmentally-friendly nature, which play a critical part in satisfying the demand of electronic devices and systems. Although it is generally accepted that EDLCs are suitable for working at low temperatures down to-40℃, there is a lack of comprehensive review to summarize the quantified performance of EDLCs when they are subjected to low-temperature environments. 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℃. 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 materials 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 perspectives to motivate more future studies to be conducted in this area.

Tailoring specific properties of polymer-based composites by using graphene and its associated compounds

Graphene and its associated compounds have been identified as extraordinary structural nano-fillers that can tailor the properties of new polymer-based composites with specific functionalities.Graphene possesses perfect 2D atomic architecture and has a large surface area that enhances the bonding,with tailored functional groups on its surface with polymer chains to form high strength composites.Recently,a lot of research has focused on developing composites with high specific strength,high electrical and thermal conductivities,high impact resistance,excellent energy storage capability and ability to maintain their strength at low-temperature environments by using graphene,graphene oxide(GO),reduced graphene oxide(rGO)or carbon nanotube/graphene.Ultimate goals are to design composites that can meet specific requirements for different engineering applications.In this paper,the discussion on all aspects in relation to the use of graphene and its associated compounds for advanced composites will be given in detail.The potentiality of using these materials for high-tech applications will be explored.Up to date,it has been proved that the use of graphene-based nanofillers does improve the mechanical,interfacial bonding,electrical,thermal and electromagnetic interference shield properties of polymer-based materials.Appropriately adding a small amount of these nanofillers do make a big difference to the properties of host materials.