Ion-Exchange Separators Suppressing Self-Discharge in Polymeric Supercapacitors

Abstract

Supercapacitors offer superior cycle life and high power densities, but as energy storage devices, they are limited by self-discharge processes manifested as large potential decay and leakage current, resulting in loss of stored energy and low charging efficiency. To minimize Faradaic side reactions, this Letter has incorporated a sulfonate ion-exchange resin in separators to trap impurities and thereby suppress self-discharge in supercapacitors with PEDOT as redox electrodes. The versatile separator design is generally applicable to organic and aqueous electrolytes and compatible with a pH range of 0− 14, while maintaining the device capacitance and rate performance. Temperature-dependent characteristics were analyzed to identify that the reduction of impurity concentration and diffusion was key to improve potential retention. Compared to devices using commercially available separators, the device here exhibited a lower leakage current and better charging efficiency. It was demonstrated to work with radio frequency energy-harvesting circuits and showed the potential to serve as an energy reservoir for wireless electronic applications.

Nano-biosupercapacitors enable autarkic sensor operation in blood

“…To suppress fast-self-discharge, a proton exchange separator (PES) can be employed 18 , 30 , 31 . The PES acts as an active barrier for the generated protons at the bioanode preventing the migration towards the biocathode, thus minimizing faradaic side reactions and leading to reduced self-discharge 19 , 20 . The PES of our nBSCs is synthesized by reacting 10% PVA with 0.003% potassium-based photo-crosslink additives in distilled water 32 .…”

“…The PES of our nBSCs is synthesized by reacting 10% PVA with 0.003% potassium-based photo-crosslink additives in distilled water 32 . The PVA based PES shows excellent electrolyte absorption properties while impeding the migration of active anions in the electrolyte and trap impurities 19 , 20 (see Fig. 2b ), directly resulting in improved charge retention and reduced self-discharge over 1.5 h in 0.9% NaCl and blood plasma electrolyte.…”

“…For the preparation of the tubular nBSCs, a stack of polymeric layers (SPL) was first deposited consisting of sacrificial, hydrogel and polyimide layers. The syntheses of each functional component of the PRS has been reported in previous works 20 , 21 . The fabrication of the SPL starts by spin-coating a ~600 nm thick sacrificial layer (La-AA) on a Si/SiO 2 substrate (O 2 plasma-cleaned).…”

“…The proton exchange separator and the compact “Swiss-roll” geometry are crucial elements to tackle self-discharge and miniaturization, respectively. The proton exchange separator acts as an active barrier for the protons generated at the bioanode, inhibiting the migration towards the biocathode, thus suppressing side redox reactions that lead to self-discharge 19 , 20 . The PVA proton exchange separator is key to retain high open voltages over 16 h and an average 40% enhancement in performance (capacity and energy storage).…”

Dual‐Gate Organic Electrochemical Transistors for Marine Sensing

“…The channel semiconductor was PEDOT:PSS etched by sulfuric acid, and the acid treatment removed PSS to form PEDOT films with improved conductivity and stability. [23][24][25] A gel electrolyte consisting of xanthan gum [26] with sodium sulfate was deposited onto the OECT channel www.advelectronicmat.de and covered by a polyvinylchloride-based membrane. The gel electrolyte increased the current modulation and response speed.…”