Continuous Energy Harvesting and Motion Sensing from Flexible Electrochemical Nanogenerators: Toward Smart and Multifunctional Textiles

Abstract

Here, we demonstrate the utilization of biocompatible Prussian blue (PB) active coatings onto polyester-carbon nanotube (CNT) threads to enable a fiber-based platform for both power harvesting and continuous motion sensing. First, we show experimental evidence supporting that the mechanistic power generating mechanical−electrochemical coupling in an electrochemical generator (ECG) is best achieved with K-ion insertion, in contrast to the expected preference for Li-ion insertion for batteries. We then construct KPB fibers and demonstrate power generation in an ECG device up to 3.8 μW/cm 2 at low frequencies relevant to human motion in either an aqueous or polymer gel electrolyte media. Further, by stitching these yarns into gloves or arm sleeves, our results show the continuous monitoring of finger or arm motion, respectively, during slow and repetitive human motion. Overall, our work demonstrates an ECG platform that overcomes the performance and integration barriers toward combined textile integration and human motion sensing while leveraging common materials and understanding extending from alkali metal-ion batteries.

Stamping Flexible Li Alloy Anodes

“…Note that flexible batteries are currently in high demand in order to meet the requirements of wearable electronic devices. [ 50 ] The pouch cell employing the printed ultrathin Li–Sn alloy anode and the NMC532 cathode showed the reliable performance to light up LED bulbs even after being folded repeatedly (Figure 4f). It is further proposed that different shapes of Li–Sn alloy anode can be continuously printed through a roll‐to‐roll process for large scale anode manufacturing (Figure 4g and Figure S6, Supporting Information).…”

Celery-derived porous carbon materials for superior performance supercapacitors

“…This assembled two-electrode supercapacitor shows a maximum energy density of 32.7 W h/kg with a power density of 1200 W/kg at 1 A/g. Even at a power density of 24 kW kg −1 , the energy density still reached 8.4 Wh kg -1 at a current density of 20 A g -1 , which is higher than those of commercially available supercapacitors (3-5 Wh kg -1 ) and other previously reported biomass-derived heteroatomdoped carbonaceous symmetric supercapacitors [58][59][60][61][62] . It is well known that the energy density was suppressed with the increase of current density since the limited pores on the surface were accessed by electrolyte ions for fast discharging at high current density, whereas almost all pores could be utilized at a low current density.…”

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

“…Compared with metal wires, aligned CNT bers are more promising candidate serving as cathode or photoanode for wearable ber-shaped solar cells, such as dye-sensitized solar cells (DSSCs), polymer solar cells and perovskite solar cells due to their lightweight, exibility, superior conductivity, high specic surface area and catalytic properties, as listed in Table 1. 14,56 Especially, the high specic surface area is favorable for the physical incorporating or chemical bonding of various active materials (i.e., photo-sensitive dyes, catalytic metal nanoparticles and transition metal oxides) into the aligned CNTs bers, improving the power conversion efficiency (PCE).…”

“…[5][6][7][8] Among a variety of power systems, the ber-shaped energy devices have been regarded as a promising strategy due to their more outstanding exibility and knittability than planar-shaped ones, and because they can be easily integrated or directly woven into various textile products with different forms. [9][10][11][12][13][14] However, there exist several great challenges in ber-shaped energy devices: (1) the relatively low capacity resulting in the repeated charging; (2) limited mechanical properties (i.e., stretchability, exibility, foldability, etc.) to withstand severe and frequent deformation during usage.…”