Designing cross‐linked pyrrole‐thieno [3,4‐ b ] thiophene copolymer to push forward electrochemical performance and access flexible micro‐supercapacitor with ultra‐long cycling stability

Abstract

Summary While higher high specific surface area allows micro‐supercapacitor (MSC) electrode materials to have improved performance, it also tends to make them less stable thermodynamically and microstructurally, which can easily deteriorate and seriously affects their service life. So here, we have chosen a cross‐linked copolymer film structure as MSC electrodes. The pyrrole‐thieno [3,4‐b] thiophene (TbT) copolymer film (namely PPy‐co‐TbT) exhibits high specific capacity, which can reach 47.8 mF cm−2 (a specific volumetric capacitance of 23.9 F cm−3 and a specific gravimetric capacitance of 28.1 F g−1) at a current density of 0.1 mA cm−2 using LiCl/PVA gel electrolyte with ultra‐long cycling stability (capacitance retention after 50 000 charge/discharge cycles is still higher than 93%, which is the leading level in MSCs). The electrochemical performance of this cross‐linked copolymer is superior to that of the single‐component polymer, achieving a 1 + 1 > 2 effect. Both features of cross‐linking and copolymerization have positive effects on microelectrodes requiring stable microstructures and high performance. The structurally stable cross‐linked copolymer obtained by copolymerization design may become a durable material for next generation ultra‐long‐life, high‐performance micro‐supercapacitor electrodes and will be widely developed. Highlights The electrochemical performance of the cross‐linked copolymer electrode reaches 1 + 1 > 2. A pioneering cross‐linked copolymer was designed to prolong the stability of microsupercapacitor. Capacitance retention rate is still higher than 93% after 50 000 cycles, which is in the leading position. Provides an important thought for the manufacture of ultra‐long‐life microsupercapacitor.

Smart copolymers of ditriphenylaminedithienothiophene with ethylenedioxythiophene for multicolor energy storage systems

“…As the feed ratio of EDOT in the copolymer structure was increased, highly improved capacitance values were observed, among which the highest C GCD was obtained with P(D1‐1E) due to its highly porous surface area and high current density resulting from high conductivity. Similar results for the copolymers with the highest capacities, obtained using equimolar fractions of monomers, were reported in separate studies 22,27,43‐46 . Interactions between S … O and S … N atoms between DTTpTPA and EDOT moieties, influenced the capacitive properties of the copolymers as their planarity increased.…”

“…GCD curves of all the polymers, recorded at different current densities, are depicted in Figure S4. Capacitance ( C GCD ), power density ( P ), and energy density ( E ) values were calculated from their GCD curves (Figure 4A) using Equations () (Figure 4B,C) 44 ; where I is the current, ( t . V ) is the area under the discharge curve, and Δ V is the potential window.…”

“…GCD curves of all the polymers, recorded at different current densities, are depicted in Figure S4. Capacitance (C GCD ), power density (P), and energy density (E) values were calculated from their GCD curves (Figure 4A) using Equations ( 2)-(4) (Figure 4B,C) 44 ;…”

“…Similar results for the copolymers with the highest capacities, obtained using equimolar fractions of monomers, were reported in separate studies. 22,27,[43][44][45][46] Interactions between S … O and S … N atoms between DTTpTPA and EDOT moieties, influenced the capacitive properties of the copolymers as their planarity increased. However, additional EDOT moiety resulted in a decrease in capacity due to decreasing intensity of Faradaic peaks belonging to DTTpTPA, indicating the importance of the critical mole ratio of the monomers, which was obtained to be the 1:1 ratio.…”

Thiophene or Pyridine-Substituted Quinoline Derivatives: Synthesis, Properties, and Electropolymerization for Energy Storage

“…Polythiophene, as a type of conductive polymer, features highly reversible doping/dedoping process, coupled with good stability as the electrode material for supercapacitors [10]. Substituting thiophene unit at 3-position with phenyl, alkoxyl, and ethyl groups has been reported to enhance the stability [11]. Further enhancement in the stability has been achieved through adding electron withdrawing groups to these substituents, like poly (3,4-ethylenedioxythiophene) [12] and poly(3-(4-fluorophenyl)thiophene) [13].…”