Hollow Polypyrrole Sleeve Based Coaxial Fiber Supercapacitors for Wearable Integrated Photosensing System

Abstract

electronics. [1][2][3][4][5][6] In order to safely and uninterruptedly drive these flexible electronics, a suitable energy storage with both fiber shape in the appearance to fit 1D geometries of integrated system and high power densities, long cycling life, and strong security in terms of electrochemical performances is extremely desired. [7][8][9] Fiber supercapacitors (SCs) that possess the features of good flexibility and weavability are considered to be one of the promising candidates due to their faster charge/discharge response and better security in comparison to Li-ions battery, Na/Mg ion battery, and photovoltaic cell and have seen a rapid development in the past few years. [10][11][12][13][14][15] To date, 1D fiber SCs are divided into two main types, including twisted and coaxial structure. [16,17] Among them, coaxial SCs have attracted more attention compared to the twisted one because of the closer distance between positive and negative electrode, more effective utilization of materials, and higher specific capacitances. [18][19][20] The core fabrication difficulty of coaxial SCs is how to form the sheath/shell-like electrode. Peng's group proposed to scroll carbon nanotube (CNT) sheet on another fiber electrode and they have demonstrated that coaxial SCs show larger specific capacitance of 59 F g −1 than that of twisted SCs (4.5 F g −1 ). [21] Although they achieved the goal of produce coaxial SCs, they failed to gain superior electrochemical performance as a result of increased contact resistance introduced by inconsecutive and rough CNT sheets. Similarly, Lee and co-workers [22] obtained coaxial structure via wrapping core fiber electrode by separator and carbon nanofiber (CNF) film. Unfortunately, the applications of separator and wrapping process bring a lot of difficulties for the ionic diffusion, maximizing material utilization and encapsulation of whole devices. [23] Therefore, it is still a big challenge to develop a simple yet efficient approach to directly fabricate coaxial SCs devices.In this work, we proposed a simple electrodeposition and etch approach to fabricate a micrometer hollow polypyrrole (PPy) sleeve based flexible coaxial fiber SCs device. The assembled coaxial fiber SCs exhibited a large volume capacitance of 2.44 F cm −3 (19.6 mF cm −2 ) and provided a power density of 0.96 W cm −3 at an area energy density of 0.07 mWh cm −3 . Moreover, the simulated results using ANSYS Maxwell software also showed a capacitance ratio of 5.14:1 between coaxial and twisted structure and demonstrated the better electrochemical performances Fiber supercapacitors (SCs) are robust power supply for wearable electronics due to their feasibility of weaving into textiles that breathe freely or integration into different functional materials that fit the curved surface of the human body. However, traditional twisted fiber SCs suffer from the low-energy density while coaxial fiber SCs undergo the complicated fabrication process of shelllike electrode. Here, a facile electrodeposition and etch approach ...

Advances on Emerging Materials for Flexible Supercapacitors: Current Trends and Beyond

“…Due to their tunable conductivity and unique doping characteristics conducting polymer based flexible supercapacitors have been widely investigated from the past few years [87] The conducting polymers [50,88] are ideally used together with pure forms of carbon as electrode materials for capacious conducting properties due to their easy dispersion. Among them Figure 8.…”

Atomic Modulation of 3D Conductive Frameworks Boost Performance of MnO2 for Coaxial Fiber-Shaped Supercapacitors

“…Notably, with the volumetric capacitance of 107.95 F cm −3 , our ACFSC device illustrates a high volumetric energy density of 48.53 mWh cm −3 and volumetric power density of 327.2 mW cm −3 obtained. These values are much greater than those of some recently reported FSC devices, such as MoS 2 @rGO@CNT [ 32 ], Au-MnO 2 @CoNi@CNT [ 33 ], Ni wire@PPy [ 34 ], MnO 2 @CNT [ 35 ], Fe 2 O 3 @C [ 36 ], and Cu@AuPd@MnO 2 [ 37 ]. A Ragone plot, representing the relationship between the energy density and power density of the ACFSC device, is shown in Fig.…”

Electronic fibers and textiles: Recent progress and perspective

“…A stretchable polymer fiber was used as the substrate for FSCs, and the series connection of adjacent single FSCs was realized through the design of shared electrodes (Shi et al, 2020). Besides, coaxial FSCs could be integrated with a photodetector to form a smart ring that display a stable optical response to white light (Figure 9B) (Li et al, 2018a).…”