Conducting polymer hydrogel materials for high-performance flexible solid-state supercapacitors

Abstract

Different from solid electrodes, conducting polymer hydrogel electrodes swollen with water and ions, can reach contact with the electrolyte solution at the molecular level, which will result in more efficient electrochemical process of supercapacitors. Besides, the inherent soft nature of hydrogel material offers the electrode superior flexibility, which benefits to gain high flexibility for devices. Here, this perspective briefly introduces the current research progress in the field of conducting polymer hydrogel electrodes-based flexible solid-state supercapacitor and gives an outlook on the future trend of research.Keywords: Conducting polymer hydrogels, flexible supercapacitor, soft electrode, polyaniline, integrated device Nowadays, flexible energy storage devices (batteries and supercapacitors) have received widely attentions as the rapid progress of flexible and wearable electronics [1,2]. Flexible solid-state supercapacitors represent a new type of supercapacitor that can work under consecutive bending, stretching and even twisting states [3][4][5]. However, it remains a large challenge to obtain a flexible solid-state supercapacitor with high electrochemical performance and superior flexibility. The performance of a flexible supercapacitor mainly depends on the properties of electrode materials and the device configuration [6]. The electrode materials of supercapacitor include various nanocarbons, conducting polymers and transition metal oxides [7][8][9][10][11][12]. Conducting polymer electrodes possess several merits, such as high electric conductivity, large capacitance, inherent flexibility and easy to processing [13][14][15][16][17][18]. However, the separations of the molecular chains in conducting polymers are generally small relative to the double layer thickness, which results in low capacitance [19]. Besides, the low ionic mobility in the polymer matrix reduces the maximum power density of such electrodes [20].On the other hand, the current device configuration of the flexible solid-state supercapacitor somewhat hinders the device to gain better performance. Generally, a flexible solid-state supercapacitor consists of a "sandwich" laminated structure, including two flexible solid electrodes and the middle gel polymer electrolyte layer [21]. In terms of this structure, the solid electrode materials hardly make a sufficient contact with the gel polymer electrolyte that possesses large viscosity and poor diffusion, which results in low capacitance and sluggish the electrochemical response.Hydrogel is made up of solid three-dimensional polymeric networks and large amounts of water medium [22]. Generally, the hydrogels are employed as solid-state electrolyte of supercapacitors, such as polyvinyl alcohol (PVA) gel polymer electrolyte. Recently, conducting polymer hydrogels were used as electrode materials for supercapacitors instead of traditional solid electrodes [19,[23][24][25]. This "aqua material electrode" is conducting polymer matrix swollen with water and ions, which hence produce a...

Flexible all-solid-state micro-supercapacitor based on Ni fiber electrode coated with MnO2 and reduced graphene oxide via electrochemical deposition

“…Up to now, various materials have been widely investigated as electrode materials for SCs, including carbon materials, conducting polymers [5] and metal oxides/hydroxides. Carbon materials, such as activated carbon [6], carbon nanotubes (CNTs) [7] and graphene [8,9], are normally used as electrode materials in EDLCs while conducting polymers and metal oxides/hydroxides in pseudo-capacitors.…”

电化学离子交换法辅助制备可用作高性能超级电容器电极的Co3O4/NiCo2O4纳米复合材料

“…5c shows the CV curves of the Co 3 O 4 /NiCo 2 O 4 electrode at various scan rates ranging from 10 to 50 mV s -1 . A pair of redox peaks can be even observed at a high scan rates, which reveals that the Co 3 O 4 /NiCo 2 O 4 electrode is favorable for fast redox reaction and ions diffusion [37,38]. With the increase of scan rates, the anodic peak shifted to higher potential …”

Recent advancements in metal organic framework based electrodes for supercapacitors

“…or conductive polymers (polyaniline, polypyrrole, etc.) [17][18][19][20]. In general, the specific capacitance of these materials is higher than that of the carbon-based materials in EDLC supercapacitor electrodes, owing to the chemical adsorption and desorption of H + in acidic electrolyte or alkali metal cations in alkaline media [21][22][23][24][25].…”