This work presents a cost and energy efficient method to manufacture thermoelectric generators (TEGs). Thermoelectric performance enhancement, cost and energy efficient manufacturing methods, and novel composite materials are foundational aspects of this work.

With the rapid development of IT, the use of electronic products has increased and maximizing the working time of electronic products without charging or replacing the battery is generally desired. Thermal energy harvesting using TEG is an attractive option to power long lastingly to electronics due to the availability of low-grade waste heat sources. It offers enormous advantages for using electronics, especially in situations where battery replacement is difficult.

Printable TEGs can be easily fabricated in high aspect ratios, which may produce high voltage outputs by forming high temperature differences in thermoelectric elements. Therefore, in order to maximize power output, a planar TEG device design is proposed and fabricated with an effective and scalable method.

By adopting chitosan with high adhesion as a binder, thermoelectric composite materials could be synthesized with a small amount of insulating binder, which consequently allowed similar electrical conductivity to the thermoelectric particles. As a post-printing process, an energy efficient uniaxial mechanical pressure was used to eliminated voids and achieve high packing density of composite thermoelectric materials. The composite materials containing heterogeneous particle sized active particles with mechanical pressing, obtained a bulk like structure and comparable electrical conductivity to bulk thermoelectric materials. The maximum figure of merit (ZT) at 300K for a p-type Bi_0.5Sb_1.5Te₃-chitosan composite was 1.0 while the ZT of an n-type bismuth-chitosan composite was 0.27.

A 9-couple TEG prototype was fabricated by manual deposition the thermoelectric composite inks on a Kevlar substrate with metal electrodes attached. The voltage generated by the prototype was measured by enforcing various currents along the circuit in a state in which a temperature difference was formed across the prototype. The prototype TEG produced a power output of 73μW at 2.9mA and 25mV for a temperature difference of 40K resulting in a device areal power density of 1181μW/cm². Power generated by this TEG prototype is sufficient to operate electronic products such as wireless devices, wearable sensors, etc.