Towards sustainable solid-state supercapacitors: electroactive conducting polymers combined with biohydrogels

Abstract

Solid-state organic electrochemical supercapacitors (OESCs) have been fabricated using poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes, a biohydrogel as electrolyte system, and polyaniline fibers as redox additive. The effectivity of sodium alginate, kappa-carrageenan, chitosan and gelatin hydrogels as electrolytic media has been evaluated considering different criteria. Results indicate that kappa-carrageenan-based hydrogel is the most suitable to perform as electrolyte due to the appropriate combination of properties: mechanical stability, ease of preparation, lack of water leaking, and good medium for the electrochemical response of PEDOT electrodes. Cyclic voltammetry and galvanostatic charge-discharge assays indicate that OESCs based on PEDOT electrodes and kappa-carrageenan hydrogel as electrolyte exhibits a good supercapacitor response in terms of specific capacitance, cycling stability, small leakage current and low self-discharging tendency. On the basis of these good properties, four OESC devices were assembled in series and used to power a red LED, confirming that, in addition to advantageous characteristics (e.g. elimination of liquid leaking and enhancement of the device compactness), the designed biohydrogel-containing OESC exhibits potential for practical applications. On the other hand, preliminary assays have been performed loading the kappa-carrageenan hydrogel with polyaniline nanofibers, which act as a redox additive. OESC devices prepared using such loaded biohydrogel have been found to be very promising and, therefore, future work is oriented towards the improvement of their design.Peer ReviewedPostprint (author's final draft

Improving the fabrication of all-polythiophene supercapacitors

“…In last years, PEDOT and its derivatives have been widely applied in the energy field, as for example to fabricate the cathode and anode in all-organic supercapacitors [18,19], electrochemical microactuators [20], and catalysts for polymer electrolyte fuel cells [21,22]. Furthermore, in a very recent study, solidstate organic electrochemical supercapacitors have been fabricated combining PEDOT 3 electrodes, a biohydrogel as electrolyte system, and polyaniline fibers as redox additive [23].…”

Nanophase-segregation in the dielectric layer enhances the charge storage capacity of polymeric electrochemical supercapacitors

“…The electrode materials for electrochemical double-layer capacitors mainly include carbonaceous species [10,11], while transition metal oxides [10,12] and conducting polymers [10,13,14] (CPs) are commonly used as electrode materials for pseudocapacitors. Because of its excellent performance, poly(3,4-ethylenedioxythiophene (PEDOT; Scheme 1) films are frequently used as electrodes for the fabrication of organic electrochemical supercapacitors (OESCs) [15][16][17][18][19][20][21]. PEDOT, which is commercialized under the trade name of Clevios ™ (Heraeus) and Baytron ® (from H. C. Starck), exhibits low band gap, easiness to stabilize the oxidized (also named p-doped) state, high conductivity and electrochemical activity, and excellent pseudocapacitance behavior [15][16][17][18][19][20][21][22][23][24][25][26][27].…”

“…Because of its excellent performance, poly(3,4-ethylenedioxythiophene (PEDOT; Scheme 1) films are frequently used as electrodes for the fabrication of organic electrochemical supercapacitors (OESCs) [15][16][17][18][19][20][21]. PEDOT, which is commercialized under the trade name of Clevios ™ (Heraeus) and Baytron ® (from H. C. Starck), exhibits low band gap, easiness to stabilize the oxidized (also named p-doped) state, high conductivity and electrochemical activity, and excellent pseudocapacitance behavior [15][16][17][18][19][20][21][22][23][24][25][26][27]. The latter been attributed to the coexistence of both (i) the redox mechanism, according to which charge is stored by electron transfer from the dopant to the polymer (i.e.…”

“…The latter been attributed to the coexistence of both (i) the redox mechanism, according to which charge is stored by electron transfer from the dopant to the polymer (i.e. ion pairing stabilizes the charge); and (ii) the double-layer behavior of doped PEDOT chains, which allows resonance throughout the conjugated structure of the polymeric backbone [15][16][17][18][19][20][21][22].…”

Electrochemical Characteristics of Polyoxometalate/Polypyrrole/Carbon Cloth Electrode Synthesized by Electrochemical Deposition Method

“…Despite this remarkable performance, the relative high cost of ruthenium for the prep-aration of ruthenium-based electrode materials limits their widespread applications. In this regard, conducting polymers, such as polyaniline and polypyrrole, have attracted great of attention as alternative materials to conventional activated carbons because of their high theoretical capacitances, high electrical conductivity, low cost, and environmental friendliness [9][10][11][12]. Although conducting polymers provide high theoretical capacitance values, conducting polymer-based electrodes suffer from poor cyclic stability due to mechanical degradation during the doping/dedoping process over long periods of time [9][10][11][12].…”