# Printed origami thermoelectric generator achieves > 20 Wm−² from low-grade heat via material and process design

## TL;DR

A new printed thermoelectric generator design achieves high power output from low-grade heat, enabling battery-free devices.

## Contribution

A high-performance Ag2(Se1-xSx)1.05-based n-type thermoelectric film with enhanced flexibility and power factor.

## Key findings

- A 65% increase in power factor compared to pristine Ag2Se films at 360 K.
- A record power density of 21 W m−2 achieved in a fully printed origami thermoelectric generator.
- The design enables low-cost, battery-free applications for wearables and IoT devices.

## Abstract

Printing facilitates low-cost thermoelectric generators to power battery-free internet-of-things devices, wearables, and Industry 4.0 systems. However, scaling up requires printable thermoelectric materials with good mechanical properties and high performance. Here, we report a high-performance Ag2(Se1-xSx)1.05-based n-type printed thermoelectric film through a combination of engineering non-stoichiometric defects and sulfur substitution. An optimal sulfur substitution of 2 at. % facilitates an excellent flexibility and a power factor of~16 µWcm−1 K−2 at 360 K, a 65 % increase compared to a pristine Ag2Se film. A fully printed origami-thermoelectric generator produces a maximum power output \documentclass[12pt]{minimal}
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\begin{document}$${P}_{\max }$$\end{document}Pmax of 907 µW at a temperature difference of 80 K. A record-high power density pd of 21 W m−2 (corresponding to 800 µW g−1 as a weight-normalized power density) is achieved, twice that of previously reported origami-thermoelectric generators. These results highlight cost-effective manufacturing of thermoelectric generators with the capability to power next-generation autonomous electronic devices.

This study reports a Ag2(Se1-xSx)1.05-based fully printed origami thermoelectric generators, achieving a high power density of 21 W m−2 at a temperature difference of 80 K. It enables low-cost, battery-free wearables and Internet-of-Things applications.