Conductive polymer is studied intensively in the last several decades. Due to its eminent properties, such as high electronic and ionic conductivity, flexible, stretchable, easy to process and so on, it is widely employed in the flexible electronics and energy storage devices.The multichannel flexible concentric – ring dry electrodes for electrophysiological recordings is developed. Conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate is utilized as the interface layer to lower the impedance and noise level. The concentric ring geometry enables Laplacian filtering to pinpoint the bioelectric potential source with spatial resolution determined by the ring distance.
Build on this flexible electrode, we develope a platform to systematically study the effects of electrical stimulation upon the inflammation phase and the activation of signaling mediators. With the help of flexible electrode, this platform enable studies of in-vivo immune cell response of electrical stimulation in the molecular level. We find that low frequency electrical stimulation increase phosphorylation of Erk proteins in recruited leukocytes, identifying a signaling pathway that is activated during the healing process.
Besides the application of conductive polymer in flexible electrode, we demonstrate a new type of faradaic electrode material comprised of a very narrow bandgap donor−acceptor conductive polymer in electrochemical supercapacitor. Due to its charge delocalization in the reduced state, the anode retain 90% of its initial capacitance after 2000 full charge – discharge cycles, which exceeds other n-dopable organic materials and is practical for commercial use. Redox cycling processes are monitored in situ by optoelectronic measurements due to the polymer’s electrochromism to separate chemical versus physical degradation mechanisms. Asymmetric supercapacitors is fabricated using this n-dopable polymer in combination with p-type PEDOT:PSS operate within a 3 V potential window, with a best-in-class energy density of 30.4 Wh/kg at a 1 A/g discharge rate, a power density of 14.4 kW/kg at a 10 A/g discharge rate.
During the electrochemical supercapacitor development, we find that self-discharge of supercapacitor is one of the bottleneck for its widely application. To solve this issue, we demonstrate a separator with sulfonate ion-exchange resin which can suppress self-discharge by trapping impurities in the electrolyte. Temperature-dependent characteristics are analyzed to identify that the reduction of impurity concentration and diffusion is key to improve potential retention. It is demonstrated to work with radio-frequency energy harvesting circuits and shows the potential to serve as an energy reservoir for wireless electronic applications.