Architectural modifications for flexible supercapacitor performance optimization

• DOI: 10.1007/s13391-016-6141-y
• Publication Date: 2016-09-08T23:35:22Z
• Authors: Jari Keskinen; Suvi Lehtimäki; Arman Dastpak; Sampo Tuukkanen; Timo Flyktman; Thomas Kraft; Anna Railanmaa; Donald Lupo
• Keywords: current collector; energy storage; 213 Electronic, automation and communications engineering, electronics; electric double layer capacitor; aqueous electrolyte; supercapacitor; substrate; 02 engineering and technology; 0210 nano-technology; 7. Clean energy

We have developed material and architectural alternatives for flexible supercapacitors and investigated their effect on practical performance. The substrate alternatives include paperboard as well as various polyethylene terephthalate (PET) films and laminates, with aqueous NaCl electrolyte used in all devices. In all the supercapacitors, activated carbon is used as the active layer and graphite ink as the current collector, with various aluminium or copper structures applied to enhance the current collectors’ conductivity. The capacitance of the supercapacitors was between 0.05 F and 0.58 F and their equivalent series resistance (ESR) was from <1 Ω to 14 Ω, depending mainly on the current collector structure. Furthermore, leakage current and self- discharge rates were defined and compared for the various architectures. The barrier properties of the supercapacitor encapsulation have a clear correlation with leakage current, as was clearly shown by the lower leakage in devices with an aluminium barrier layer. A cycle life test showed that after 40000 charge-discharge cycles the capacitance decreases by less than 10%.