Weavable asymmetric carbon nanotube yarn supercapacitor for electronic textiles

Abstract

Asymmetric supercapacitors are receiving much research interests due to their wide operating potential window and high energy density. In this study, we report the fabrication of asymmetrically configured yarn based supercapacitor by using liquid-state biscrolling technology. High loading amounts of reduced graphene oxide anode guest (90.1 wt%) and MnO 2 cathode guest (70 wt%) materials were successfully embedded into carbon nanotube yarn host electrodes. The resulting asymmetric yarn supercapacitor coated by gel based organic electrolyte (PVDF-HFP-TEA$BF 4 ) exhibited wider potential window (up to 3.5 V) and resulting high energy density (43 mW h cm À2). Moreover, the yarn electrodes were mechanically strong enough to be woven into commercial textiles. The textile supercapacitor exhibited stable electrochemical energy storage performances during dynamically applied deformations.There is an especially important need for weavable yarn-based supercapacitors that can be used in electronic textiles. Yarnbased batteries can provide high specic energy storage capabilities, but their typically low charge and discharge rates are a problem for rapidly storing the energy generated by energy harvesters operating at the frequencies of body motion, or delivering high electrical power when needed.Yarn or ber based supercapacitors have advantages over conventional three-or two-dimension (3D, 2D) energy storage devices for powering wearable electronics, which can include micron-scale diameters, light weight, exibility or stretchability, and weavability into textiles.1-7 However, the energy storage densities of supercapacitors are lower than for the best batteries. In order to achieve high energy storage density for yarn or ber based supercapacitors, previous research has been conducted in two directions: one is to increase the capacitance (C) of the device by introducing pseudocapacitive materials, while the other is to widen the voltage window (V) of electrochemical operation by using asymmetric electrodes. Since the stored electrical energy is given by E ¼ 1/2CV 2 , both strategies are important. Environmentally friendly, cost-effective, highly performing metal oxides (MnO 2 ) 8,9 or various conducting polymers (e.g., poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANI), polypyrrole (PPy)) 2,10-14 have been extensively studied as pseudocapacitive additives to dramatically improve the charge storage capability of 1D supercapacitors. Asymmetrically congured 1D supercapacitors used active materials like graphene, carbon nanotubes (CNTs), and PPy for anode yarns and materials like MnO 2 , MoS 2 , Ni(OH) 2 , Co 3 O 4 for cathode yarns, resulting in voltage windows between 1.5 V and 1.8 V. 15-22In this study, we realized ber supercapacitors having both high specic capacitances and increased potential windows. The rst utilized strategy was to trap pseudocapacitive guest materials within vascular, high electrical conductivity networks of twist-spun CNT yarns, which maximized the weight percent of the guest without sig...

Preparation of NiO decorated CNT/ZnO core-shell hybrid nanocomposites with the aid of ultrasonication for enhancing the performance of hybrid supercapacitors

“…Further, the device shown good performance under high current density of 25 mA cm −2 with an areal energy density of ~20 µWh cm −2 at a high power density of 16.25 mW cm −2 . The obtained areal energy density and power density values of the present supercapacitor are larger than the values of recently reported CNT based SCs [27] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] . As the cycling stability is particularly important to employ the device in practical applications, the cycling test was conducted for 6000 cycles.…”

Recent Advances in Sustainable Wearable Energy Devices with Nanoscale Materials and Macroscale Structures

“…In another example, MnO 2 @CNT fiber and rGO/CNT fiber electrodes were fabricated via a liquid-state biscrolling method, as shown in Figure 16d. [244] Owing to the high loading of the guest materials (rGO: 90.1 wt%, MnO 2 : 70 wt%), the fabricated asymmetric SCs exhibited an enhanced energy density of 43 µWh cm −2 .…”

“…Reproduced under the terms of Creative Commons Attribution 3.0 Unported License. [244] Copyright 2018, The Authors, published by Royal Society of Chemistry. e) Schematic illustration showing the fabrication of a spring-like coiled fiber SCs with a stretchable rubber support.…”

Aligned carbon nanotube fibers for fiber-shaped solar cells, supercapacitors and batteries

“…Aligned CNT bers with excellent conductivity, outstanding mechanical properties and high specic surface area are promising for constructing ber-shaped supercapacitors. [81][82][83][84][85] However, the lower energy density of CNT ber-based bershaped supercapacitor resulted in frequent charge/discharge during practical application, difficult to satisfy the actual requirement. According to the equation E ¼ CV 2 /2, the energy density (E) is proportional to specic capacitance (C).…”