Flexible Asymmetrical Solid-State Supercapacitors Based on Laboratory Filter Paper

Abstract

In this study, a flexible asymmetrical all-solid-state supercapacitor with high electrochemical performance was fabricated with Ni/MnO2-filter paper (FP) as the positive electrode and Ni/active carbon (AC)-filter paper as negative electrode, separated with poly(vinyl alcohol) (PVA)-Na2SO4 electrolyte. A simple procedure, such as electroless plating, was introduced to prepare the Ni/MnO2-FP electrode on the conventional laboratory FP, combined with the subsequent step of electrodeposition. Electrochemical results show that the as-prepared electrodes display outstanding areal specific capacitance (1900 mF/cm(2) at 5 mV/s) and excellent cycling performance (85.1% retention after 1000 cycles at 20 mA/cm(2)). Such a flexible supercapacitor assembled asymmetrically in the solid state exhibits a large volume energy density (0.78 mWh/cm(3)) and superior flexibility under different bending conditions. It has been demonstrated that the supercapacitors could be used as a power source to drive a 3 V light-emitting diode indicator. This study may provide an available method for designing and fabricating flexible supercapacitors with high performance in the application of wearable and portable electronics based on easily available materials.

Flexible Asymmetric Microsupercapacitors from Freestanding Hollow Nickel Microfiber Electrodes

“…At low scan rate, the shape of the curve is almost rectangular ( Figure S3, Supporting Information), indicating pseudocapacitive behavior. [27,40] Nevertheless, the capacitance exhibited by the MnO 2 -coated Ni microfiber electrode exhibits superior performance compared with recently reported thinfilm supercapacitor electrodes. Capacitance decrease and concomitant loss of rectangular shapes of the CV curves are common upon high loading of the active materials in pseudocapacitors and ascribed to the higher resistance developed in the pseudocapacitive layer.…”

“…Other strategies have focused on chemical means for creation of porous electrode exhibiting high surface areas, serving as a scaffold for deposition of the electrochemically active material. [27][28][29] Yet, even in those systems, removal of the electrode substrate-supports was difficult, thereby limiting their usefulness. [26] While such electrode designs provide high capacitance, they usually exhibit considerable thickness, [23][24][25][26] making them less suitable for integration in microelectronics.…”

“…[30,31] While MSCs exhibiting high flexibility and mechanical resilience have been reported, they are either too bulky, [27,32] or the devices display limited electrochemical performance. Thin MSCs that can withstand folding without significant degradation in performance are highly sought.…”

“…A final step of toluene-induced dissolution of the PS cores yielded a freestanding electrode comprising an interspersed network of hollow metallic nickel microfibers. [19,27] The mechanical resilience of the hollow microfiber Ni electrode upon physical deformation was evaluated ( Figure 2D,E). Scanning electron microscopy (SEM) images in Figure 2A-C show the intertwined network of highly uniform Ni microfibers, exhibiting outer diameters of 3.4 ± 0.6 µm and inner diameter of 1.8 ± 0.2 µm.…”

Fe3O4/Nitrogen‐Doped Carbon Electrodes from Tailored Thermal Expansion toward Flexible Solid‐State Asymmetric Supercapacitors

“…Interfaces 2019, 6,1901250 also considerably higher than those of a number of recent solid-state energy storage devices including including N-G/ layered MnO 2 //AC, [60] MnO 2 /rGO//MoO 3 /rGO, [61] MnO 2 @ CNT@3DGA//PPy@CNT@3DGA, [62] MnO 2 @g//VOS@C, [63] MnO 2 //Ti-Fe 2 O 3 @PEDOT, [64] MnO 2 @Ni@FP//AC@Ni@FP, [65] α-Fe 2 O 3 //MnO 2 , [66] MnO 2 @CNT//PPy@CNT, [67] CNT//CNT/ Mo 3-x , [68] MnO 2 @NNA//PPy@NNA, [69] Ag/MnO 2 //Ag/MoO 3 , [70] and Fe 2 O 3 //MnO 2 . Mater.…”