Enhanced electrical conductivity and stretchability of ionic-liquid PEDOT:PSS air-cathodes for aluminium-air batteries with long lifetime and high specific energy

Abstract

A hydrogel film, poly-3,4-ethylenedioxythiophene (PEDOT):polystyrenesulfonate (PSS), containing an ionic liquid, is used as an air–cathode for a metal-air battery and its performance is investigated. This work presents the development of the air–cathode and the characterization of its physical, chemical and mechanical properties. Moreover, in view of wearable batteries, these air-cathodes are implemented within a flexible aluminium-air battery. It contains an aluminium anode, an electrolyte made of cellulose paper imbibed with an aqueous sodium chloride solution and the PEDOT:PSS air–cathode. Characterisation tests showed that the ionic liquid did not change the air–cathode chemically, while the electric conductivity increased considerably. The anode has an acceptable purity and was found to be resistant against self-corrosion. Discharge tests showed operating voltages up to 0.65 V, whereas two batteries in series could deliver up to 1.3 V at a current density of 0.9 mA cm−2 for almost a day, sufficient for monitoring and medical devices. Several discharge tests with current densities from 0.25 up to 2.5 mA cm−2 have presented operating lifetimes from 10 h up until over a day. At a current density of 2.8 mA cm−2, the operating voltage and lifetime dropped considerably, explained by approaching the limiting current density of about 3 mA cm−2, as evidenced by linear sweep voltammetry. The batteries showed high specific energies up to about 3140 Wh kg−1. Mechanical tests revealed a sufficient stretchability of the air–cathode, even after battery discharge, implying an acceptable degree of wearability. Together with the reusability of the air–cathode, the battery is a promising route towards a low-cost viable way for wearable power supply for monitoring medical devices with long lifetimes and high specific energies. Optimization of the air–cathode could even lead to higher power applications.

Boosting the Performance of PEDOT:PSS Based Electronics Via Ionic Liquids

“…An integral constituent of a battery, the electrode typically constitutes a multi‐component system encompassing electrode particles, conductive agents, binders, and current collectors. [ 169 ] Si electrodes stand as one of the most promising anode materials for lithium‐ion batteries (LIBs), offering a notably high theoretical specific capacity of up to 4200 mAh g −1 . However, during lithiation and delithiation, these electrodes undergo substantial volume expansion, leading to material fracturing and detachment from the current collector.…”

Ionic‐electronic coupling in PEO‐PEDOT/potassium triflate composite films for organic mixed conductivity enhancement

“…nanoparticles, known for their high electronic conductivity 37,38 in conjunction with complex ions of KOTf (Potassium triflate) 35 integrated into a polyethylene oxide (PEO) film which possesses exceptional ionic transport properties. 25,26 The electrical conductivity of the resulting PEO-PEDOT/KOTf composite films was assessed through four-point probe measurements conducted at various temperatures.…”

“…As previously delineated, composite films based on organic mixed ionic‐electronic conductors (OMIECs) demonstrate a dual effect, encompassing ionic transports facilitated by polyelectrolytes and electronic transport facilitated by conjugated polymers. In the context of this investigation, we present a novel OMIECs‐based composite film comprising PEDOT (Poly(3,4‐ethylenedioxythiophene)) nanoparticles, known for their high electronic conductivity 37,38 in conjunction with complex ions of KOTf (Potassium triflate) 35 integrated into a polyethylene oxide (PEO) film which possesses exceptional ionic transport properties 25,26 …”

Electropolymerized poly(3,4-ethylenedioxythiophene) coatings on porous carbon electrodes for electrochemical separation of metals

“…[46][47][48] More recently, PEDOT has been investigated as an electrode (coating) for other energy applications such as Li-ion and metal-ion batteries, redox flow batteries and supercapacitors. [49][50][51][52][53] Interested readers can refer to the extensive reviews on the properties and applications of this polymer. [54,55] PEDOT is a p-type conductive polymer where the reduced form of the polymer is neutral and the oxidized form is positively charged.…”