A research team at a unverity in South Korea has developed a product that allows body heat to generate electricity to power electronic devices. This could pave the way for battery-free wearable gadgets and Internet of Things (IoT) sensors that operate solely on heat generated by the human body.
Led by Professor Sung-Yeon Jang from the School of Energy and Chemical Engineering at UNIST (Ulsan National Institute of Science and Technology in South Korea), the research team developed the world's first high-performance n-type solid-state thermogalvanic cell capable of powering actual electronic devices. The paper is published in the journal Energy & Environmental Science.
Thermogalvanic cells are compact generators that convert temperature differences—such as the human body temperature (~36°C) versus surrounding air (20–25°C)—into electrical energy. However, due to the minimal temperature gradient, previous systems struggled to produce enough power to operate real-world electronics.
The newly developed solid-state device overcomes this challenge by delivering sufficient voltage and current to power practical devices. While solid-state designs typically offer advantages such as safety from leakage, ion mobility issues within the electrolyte have historically limited their current output. The research team engineered an electrolyte that facilitates efficient ion transport, and further, the thermally driven ion diffusion enhances overall output voltage.
By connecting 100 of these cells in series—similar to building with Lego blocks—approximately 1.5V can be generated from body heat, comparable to standard AA batteries. Connecting 16 such series-connected modules enables the activation of devices like LED lights, electronic clocks, and temperature/humidity sensors.