Flexible Fiber-Shaped Supercapacitor Based on Nickel–Cobalt Double Hydroxide and Pen Ink Electrodes on Metallized Carbon Fiber

Abstract

Flexible fiber-shaped supercapacitors (FSSCs) are recently of extensive interest for portable and wearable electronic gadgets. Yet the lack of industrial-scale flexible fibers with high conductivity and capacitance and low cost greatly limits its practical engineering applications. To this end, we here present pristine twisted carbon fibers (CFs) coated with a thin metallic layer via electroless deposition route, which exhibits exceptional conductivity with ∼300% enhancement and superior mechanical strength (∼1.8 GPa). Subsequently, the commercially available conductive pen ink modified high conductive composite fibers, on which uniformly covered ultrathin nickel-cobalt double hydroxides (Ni-Co DHs) were introduced to fabricate flexible FSSCs. The synthesized functionalized hierarchical flexible fibers exhibit high specific capacitance up to 1.39 F·cm in KOH aqueous electrolyte. The asymmetric solid-state FSSCs show maximum specific capacitance of 28.67 mF·cm and energy density of 9.57 μWh·cm at corresponding power density as high as 492.17 μW·cm in PVA/KOH gel electrolyte, with demonstrated high flexibility during stretching, demonstrating their potential in flexible electronic devices and wearable energy systems.

Utilizing Waste Cable Wires for High‐Performance Fiber‐Based Hybrid Supercapacitors: An Effective Approach to Electronic‐Waste Management

“…When the potential is extended from 0 to 0.8 V and 0 to 1.55 V, interestingly, there is no obvious of H 2 /O 2 evolution in the CV plots and no overcharging region in the GCD plots was noticed, signifying the good electrochemical operation stability and maximum potential window of the device (1.55 V). The obtained energy density of our device is higher or comparable with those of the previously reported fiber-based solid-state SCs, such as NiCo 2 O 4 //PC (6.61 W h kg −1 ), [22] Ni 3 S 2 /Ni//pen ink (8.2 W h kg −1 ), β-Ni(OH) 2 //AC (9.8 W h kg −1 ), [23] NiCo 2 O 4 //pen ink (7.66 W h kg −1 ), [24] meshtype CuO@MnO 2 //activated graphene (29.9 W h kg −1 ), [25] and MnO 2 //graphene (27.2 W h kg −1 ), [26] respectively and some planar SCs, such as Cu 2 O/CuO/Co 3 O 4 //activated graphene (12 W h kg −1 ), [27] CuO//AC (19.7 W h kg −1 ), [28] and core-shell Ni 3 S 2 @CoS//AC (23.69 W h kg −1 ), [29] and MnFe 2 O 4 //LiMn 2 O 4 (5.5 W h kg −1 ), [30] respectively. Figure 5d shows the CV curves of the FHSC tested at various scan rates of 5-70 mV s −1 with a stable potential window of 0-1.55 V. Distinctive from the solid redox peaks observed in three-electrode system, the CV curves of the fabricated FHSC exhibited the excellent capacitive behavior due to the inclusion of EDLC material.…”

Ternary composite solid-state flexible supercapacitor based on nanocarbons/manganese dioxide/PEDOT:PSS fibres

“…Therefore, the incorporation of active materials into the fibre represents a real alternative as the ion and electron transportations are facilitated. Flexible fibres with higher psuedocapacitive material contents and excellent capacitance values are obtained [16][17][18][19]. However while such a combination of materials and strategy can yield excellent charge storage capabilities, the steps involved in fibre formation are complex and not easily scalable.…”

Biomimetic and Radially Symmetric Graphene Aerogel for Flexible Electronics

“…[13,51] Briefly, the rGO/NW fabricated at 20 s was directly used as the working electrode and immersed into the 100 mL of a solution consisting of 40 mm Co(NO 3 ) 2 ·6H 2 O and 40 mm Ni(NO 3 ) 2 ·6H 2 O. Hg/HgO electrode was regarded as the reference electrode, and Pt foil (1 cm × 1 cm) acted as the counter electrode. [13,51] Briefly, the rGO/NW fabricated at 20 s was directly used as the working electrode and immersed into the 100 mL of a solution consisting of 40 mm Co(NO 3 ) 2 ·6H 2 O and 40 mm Ni(NO 3 ) 2 ·6H 2 O. Hg/HgO electrode was regarded as the reference electrode, and Pt foil (1 cm × 1 cm) acted as the counter electrode.…”

“…[51] In a typical procedure, a certain amount of poly(vinyl alcohol) (PVA, 3 g) was initially added into 20 mL of DI water with seriously stirring at 90 °C for 2 h until the solution becomes clear. [51] In a typical procedure, a certain amount of poly(vinyl alcohol) (PVA, 3 g) was initially added into 20 mL of DI water with seriously stirring at 90 °C for 2 h until the solution becomes clear.…”

“…[36,51] As shown in Figure 6a, the NiCo-LDH would show high electron transportation rate because of the existed high conductivity of the graphene layer. Here we give an example of using the GF scaffold to deposit the battery-type materials of NiCo layered double hydroxide (NiCo-LDH) and Zn flakes to assemble the fiber-shaped Ni-Zn battery to enrich our previous works.…”