Thermoelectric textile with fibers coated by copper iodide thin films

Abstract

Here we obtained thermoelectric (TE) textiles on the base of the commercial cotton and polyester fabrics. For this we used deposition of copper iodide (CuI) thin films via low-temperature cheap and scalable method Successive Ionic Layer Adsorption and Reaction (SILAR). The TE textiles are comfortable to wear, breathable, nontoxic, light-weight, flexible and air-permeable. The CuI films in the TE textiles are composed of accreted flakes with nanoscale thickness (<50 nm) or of nanowalls. Their crystal grains are less than 50 nm, contain a significant number of dislocations and an increased lattice parameter, and consequently have large compression microstrains. The TE textiles with CuI coated cotton and polyester have the Seebeck coefficients in the range of 120–180 μV K−1, which are constant at the temperatures 290–365 K. The most effective single p-CuI thermoelectric leg has low internal resistance 2 kΩ. Its specific output power at temperature gradient 50 K is 31 μW/m2. Three experimental flexible wearable TEGs of simple and affordable designs having each four thermocouples with n-Alumel and p-CuI thermoelectric legs on the thick cotton, thin cotton and polyester confirm the possibility of obtaining electricity using the developed TE textiles under conditions of temperature gradients from 5 to 50 K at near-room temperatures. The best TEG obtained on the polyester fabric has at temperature difference 50 K output TE characteristics: open circuit voltage 44 mV, short circuit current 1.3 µA, output power 16 nW. These characteristics remain unchanged after repeated bends of TEGs in the different directions.