Waterborne polyurethane: an easily available material for moist-electric generator with unique stretchability and water resistance

Abstract

Moisture-enabled electricity generation (MEG) is a new type of green power generation that has attracted a lot of attention in recent years. It converts chemical energy into electrical energy by generating a voltage through the interaction of a hygroscopic material with moisture. However, these materials tend to be hydrophilic and rigid, limiting the application scenarios of MEG. Herein, we have found for the first time, a waterborne polyurethane (WPU), which can generate electricity with moisture, has good water resistance and can be stretched and is also green and easy to process. A composite film with an asymmetric structure was obtained by mixing it with silver nanowires (AgNWs) and simple physical deposition and drying. A single MEG unit of 0.25 cm² can produce an open-circuit voltage of 0.3 V and a short-circuit current of 0.946 μA, which can be retained after washing up to 50 times and for up to 1000 stretching cycles. Such an integrated device viably drives an LED bulb or a calculator and can be easily integrated into fabric. This work provides a more realistic material system for MEG materials.