Energy Harvesting Materials and Structures for Smart Textile Applications: Recent Progress and Path Forward

Abstract

A major challenge with current wearable electronics and e-textiles, including sensors, is power supply. As an alternative to batteries, energy can be harvested from various sources using garments or other textile products as a substrate. Four different energy-harvesting mechanisms relevant to smart textiles are described in this review. Photovoltaic energy harvesting technologies relevant to textile applications include the use of high efficiency flexible inorganic films, printable organic films, dye-sensitized solar cells, and photovoltaic fibers and filaments. In terms of piezoelectric systems, this article covers polymers, composites/nanocomposites, and piezoelectric nanogenerators. The latest developments for textile triboelectric energy harvesting comprise films/coatings, fibers/textiles, and triboelectric nanogenerators. Finally, thermoelectric energy harvesting applied to textiles can rely on inorganic and organic thermoelectric modules. The article ends with perspectives on the current challenges and possible strategies for further progress.

Keywords: energy harvesting; photovoltaic; piezoelectric; smart textiles; thermoelectric; triboelectric.

Figure 1

Examples of textile structures relevant to energy harvesting devices: (a) woven; (b) knit; (c) nonwoven mat (source: Md. Rashedul Islam, with permission).

Figure 2

Examples of recent developments toward photovoltaic energy harvesting materials and structures for textile application: (a) different geometries of titanium nanopillars used as electron transporting layer in inorganic flexible solar cells (reproduced from [33] with permission from Wiley); (b) ternary polymer used as active layer in organic photovoltaic cells (reproduced from [36] with permission from Wiley); (c) porosity and morphology of PVDF-HFP/PEO microporous membrane used in gel-like dye-sensitized solar cells (reproduced from [37] with permission from Elsevier).

Figure 3

Examples of recent developments toward photovoltaic energy harvesting materials and structures for textile application: image by high-resolution transmission electron microscopy of double perovskites after annealing: Cs₂SnI₆ (a–c), Cs₂SnI₂Cl₄ (d–f), Cs₂SnCl₆ (g–i), with Raman spectra of the graphene oxide nanoparticles formed shown in inserts in a, d, and e (reproduced from [62], with permission from ACS Publications).

Figure 4

Examples of recent developments toward piezoelectric energy harvesting materials and structures for textile application: (a–d) SEM images of piezoelectric electrospun PVDF fibers of different diameters (e) exhibiting different open circuit output voltages (f) (reproduced from [73], available through the Creative Commons license (creativecommons.org/licenses/by/4.0/)).

Figure 5

Examples of recent developments toward piezoelectric energy harvesting materials and structures for textile application: (a) PZT-PVDF nanocomposite nanofibers (reproduced from [80] with permission from Elsevier); (b) array of vertical ZnO nanorods on a silver coated polyamide fabric (top left cartoon: PENG structure, top right picture: uncoated woven fabric, bottom left picture: silver-coated fabric, bottom right picture: ZnO nanorods-coated fabric, reproduced from [83] with permission from Elsevier).

Figure 6

Examples of recent developments toward triboelectric energy harvesting materials and structures for textile application: (a) TiO₂ flowers decorating a stainless steel textile (reproduced from [96] with permission from Elsevier); (b) CNT decorating a velvet fabric (reproduced from [100] with permission from ACS Publications).

Figure 7

Example of recent developments toward triboelectric energy harvesting materials and structures for textile application: core-spun yarns composed of silk (a) and PTFE (b) fibers wrapped around a stainless steel fiber (SSF) core (reproduced from [104], available through the Creative Commons license (creativecommons.org/licenses/by/4.0/).

Figure 8

Example of recent developments toward triboelectric energy harvesting materials and structures for textile application: 3D TENG composed of a double-faced interlock knit containing polyamide (PA) 66 yarns coated with silver and silicone rubber and cotton yarns (reproduced from [112], with permission from Elsevier).

Figure 9

Examples of recent developments toward thermoelectric energy harvesting materials and structures for textile application: (a) MWCNT film before and after doping with PEI, used respectively as the p- and n-type thermoelectric legs (reproduced from [132] with permission from ACS Publications); (b) DMSO/PEDOT: PSS coated silk yarn used to prepare an out-of-plane thermoelectric device (reproduced from [138], available through the Creative Commons license (creativecommons.org/licenses/by/4.0/)).