A highly integrated blade structure for thermoelectric devices with ultra-high output voltage and power densities

Abstract

Thermoelectric (TE) technology can convert human body heat into useful electricity, providing a promising solution to develop self-powered wearable electronics, in which both high output voltage density and power density are urgently required. However, the existing TE devices usually possess low voltage density in the wearing condition, greatly limiting their real applications. In this work, we propose a novel highly integrated blade structure, which can achieve ultrahigh output voltage and power densities. The finite element simulation gives the optimal geometric dimensions and integration numbers of the TE legs for the blade structure. In the experiment, we successfully fabricated the blade TE device by using the recently discovered Ag-based ductile inorganic TE materials with the TE leg density and aspect ratio of 300 cm⁻² and 1250 cm⁻¹, respectively. Such high values have not been simultaneously achieved for the TE devices reported before. An ultrahigh voltage density of up to 869.6 mV cm⁻² is achieved when the blade device is worn on the human body, which is at least one order of magnitude higher than the existing TE devices. Likewise, the blade TE devices also exhibit high power density up to 114.1 µW cm⁻², among the highest values reported so far. The electricity converted from body heat by the blade TE device can directly power an electronic watch, showing great potential to be used in real applications.