Can body temperature generate electricity? Chinese scientists achieve material breakthrough!

Recently, the team of Professor Zhang Qian and Professor Mao Jun from the School of Materials Science and Engineering at Harbin Institute of Technology (Shenzhen) has made a new breakthrough in the field of plastic thermoelectric materials: they found that magnesium bismuth single crystals have both excellent plastic deformation ability and excellent thermoelectric performance at room temperature. The relevant results were published in the international journal Nature on the 10th.

01 Bendable and twistable magnesium bismuth single crystal

The research team prepared centimeter-level high-quality magnesium bismuth single crystals. "Magnesium bismuth single crystals can easily achieve various types of plastic deformations such as bending and twisting at room temperature." Zhang Qian introduced that the optimized magnesium bismuth single crystals also showed excellent thermoelectric properties at room temperature, which is better than the current plastic semiconductor materials.

It is reported that this type of plastic thermoelectric material can be used to develop flexible thermoelectric devices, mainly for application scenarios such as power generation and temperature control based on human body temperature.

02 The magical technology of generating electricity from human body temperature

Body temperature power generation is a method of generating electricity by using the temperature difference between the body surface and the external environment, which makes it possible for electronic devices to get rid of traditional power supply methods. In 2007, scientists from the Fraunhofer Institute for Integrated Circuits in Germany explored this new technology. They used semiconductors to obtain electrical energy by using temperature differences. The basic principle of temperature difference power generation is the "Seebeck" effect, that is, when two different metals are connected to form a closed loop, if the temperatures of the two connection points are different, a small voltage can be generated.

In 2016, researchers at North Carolina State University in the United States invented a "charging patch" that can easily convert body heat into electrical energy. It is only 2 mm thick and can be folded at will. The bottom layer is a heat-conducting material that fits tightly to the skin, and it is covered with a polymer film to prevent heat loss. This structure can "force" heat to pass through the temperature difference generator inside, thereby converting heat into electrical energy.

03 Breakthrough in Body Temperature Power Generation Technology in my country

In 2018, the Institute of Metal Research of the Chinese Academy of Sciences developed a new material that can generate electricity using body temperature. This new material is a single piece of gray soft film that is less than a finger wide and 0.1 mm thick. When it is attached to the human wrist, the connected measuring meter immediately shows a significant output voltage. It will power wearable electronic devices such as Bluetooth headsets, health monitors, watches, and smart bracelets.

When using human body temperature to generate electricity, when the difference between body temperature and ambient temperature is about 15 degrees Celsius, microwatt-milliwatt power generation can be achieved. The power generation effect increases with the increase of temperature difference, especially when the human body consumes biochemical energy to generate heat during exercise or when the annual average outdoor temperature in northern regions is below 20 degrees Celsius. As long as there is a temperature difference, power generation can be achieved, whether the body temperature is higher than the ambient temperature or the ambient temperature is higher than the body temperature.

The thin-film battery made of the above-mentioned new material, namely the "flexible, tailorable bismuth telluride/cellulose composite thermoelectric thin-film battery", combines high-performance bismuth telluride thermoelectric material with low-cost cellulose paper in a network structure. It also has excellent deformation ability, can fully conform to the human body surface with complex curvature changes, and maintain the temperature difference with the surrounding environment, thereby improving the thermal energy conversion efficiency. It can be applied to the new generation of low-power microsystem power supply technology.

With the development of wearable electronic products, scientists at home and abroad have begun to focus on the research of flexible thermoelectric materials and devices in recent years.

Comprehensive sources: Science and Technology Daily, CCTV News, Xinhuanet, etc.