One-step wet-spinning process of CB/CNT/MnO2 nanotubes hybrid flexible fibres as electrodes for wearable supercapacitors

Abstract

Fibres made from different nanostructured carbons (carbon black (CB)), carbon nanotubes (CNT) and CB/ CNT were successfully developed by wet-spinning. The variation of dispersion conditions (carbon nanomaterial concentration, dispersant/Carbon nanomaterial concentration ratio, CB/CNT concentration ratio, pH) resulted in different electrochemical performance for each type of fibres. Fibres with the best capacitance values (10 F g −1) and good cycling stability (89%) were obtained from fibres containing 10% carbon black and 90% carbon nanotubes. A solid-state supercapacitor was fabricated by assembling the CB/CNT fibres resulting in 9.2 F g −1 electrode capacitance. Incorporation of 0.2 wt% birnessite-type potassium manganese oxide nanotubes dramatically increased the capacitance of the fibres up to 246 F g −1 due to the high specific capacitance of birnessite phase and the tubular nature of the nanomaterial.

Solvent Treatment of Wet-Spun PEDOT: PSS Fibers for Fiber-Based Wearable pH Sensing

“…Similar conductivity values were measured for all fiber treatment times with no further improvement observed for longer times (either 60 or 120 min), suggesting that all modification of the fibers occurred within the first 5 min. Xia et al found that the conductivity increased after treatment with dilute sulfuric acid for up to three treatments [13]. For the solvents used here, the treatments were repeated with multiple immersions, showing no further increase after the first submersion.…”

“…This trend however was not observed with other PEDOT: PSS sources (as shown later in Figure 4). This is partially attributed to the removal of insulating PSS from the fiber, specifically from the fiber surface and the reordering of the polymer chains and is discussed later in the sections dealing with Raman spectroscopy and XPS [7,13,15].…”

“…Electrically conducting fiber electrodes have been fabricated from carbons such as carbon nanotubes [5] and graphene [6] and conducting polymers such as polyaniline (Pani) [7], polypyrrole [8], and polyethylene dioxythiophene (PEDOT) [9]. Conducting polymers are particularly appealing for electronic textiles due to their intrinsic electrical and electrochemical properties such as high electrical conductivity, electrochemical switching, and charge storage [10,11,12,13]. The ease with which they can undergo solution processing allows continuous conductive fiber production using simple wet-spinning.…”

Perspectives for electrochemical capacitors and related devices

“…This area emerged less than ten years ago 117 and keeps growing because of the interest in 'wearable Internet' and smart textiles 110 . Initially, carbon materials were used, but conductive polymers, metal oxides 118 and MXenes 119 recently entered the field. Storing the amount of energy required for powering devices, from LEDs to sensors and communication (antennas) on the limited surface of a garment (less than 1 m 2 ) is challenging, if only EDLC is used.…”

One-step direct fabrication of manganese oxide electrodes by low-temperature thermal decomposition of manganese formate-amine ink for supercapacitors

“…MnOx composite electrodes fabricated on flexible substrates are being examined for use as supercapacitors [63][64][65][66] We previously reported a single-material electrode of manganese oxide that resulted in a high level of specific capacitance [9]. That version's high specific capacitance was due to the morphology of the multi-plate thin film, which was fabricated via the thermal decomposition of manganese formate-amine ink at 260 o C.…”