Four basic operating modes of friction nanogenerator

Collect physical photos of TENG in various forms of mechanical energy. These TENG and corresponding mechanical energy forms include: (a) the energy of finger tapping; (b) Air movement and wind energy; (c) in-plane sliding energy; (d) The closed cavity TENG is used to collect water energy and mechanical vibration energy; (e) The kinetic energy of human motion that can be collected with textiles; (f) Use transparent TENG to collect energy for touch screen operation; (g) Energy of foot and hand clapping; (h) Impact energy of water; (i) Cylindrical TENG is used to collect rotational energy; (j) The TENG placed in the shoe is used to collect the energy of walking; (k) A flexible grid structure to collect sliding energy; (l) Disk TENG is used to collect rotational energy (this image has been licensed by the Royal Society of Chemistry)

Based on the four basic working modes described above, we have prepared various TENG structures for specific applications. FIG. 2 is a picture of the TENG we prepared for collecting different forms of mechanical energy. These structures are the basic components that provide micro and nano energy for small electronic devices, and by integrating multiple such basic components together, it is possible to use this basic principle for large-scale power generation.

Maxwell Shift Current's future Emerging Industries: Energy and Sensing

The extensive economic, cultural, and political connections that modern society has established through broadcasting and communication satellites over the past 20 centuries are directly attributable to the displacement current term of Maxwell's equations. The history of physics holds that Newton's classical mechanics opened the door to the mechanical age, while Maxwell's theory of electromagnetism laid the cornerstone for the information age. In 1931, Einstein described Maxwell's work as "the most profound and fruitful work in physics since Newton."

From 1886 to the 1930s, the electromagnetic wave theory was first derived from the displacement current, and the electromagnetic induction phenomenon gave birth to antenna broadcasting, television telegraphy, radar microwave, wireless communication and space technology. In the 1960s, the theory of electromagnetic unified production of light provided an important physical theoretical basis for the invention of laser and the development of photonics. In addition, the control and navigation of aircraft, ships and spacecraft, and the technological advances in the power and microelectronics industries are inseparable from Maxwell.

Since 2006, the second component of displacement current, based on the characteristics of media polarization, has spawned the rise of piezoelectric nanogenerators and friction nanogenerators, which will greatly promote the development of new energy technology and self-powered sensor technology. The nanogenerator energy system is widely used in major aspects affecting future human development such as the Internet of Things, sensor networks, blue energy and even big data. After more than 150 years of space-time imprint, tracing back to the source, the nanogenerator is another important application of Maxwell displacement current in energy and sensing after electromagnetic wave theory and technology.

Major fundamental scientific, technical, and industrial implications derived from the two components of Maxwell's displacement current. On the left is derived electromagnetic wave theory that influenced the development of communication technology in the 20th century; On the right are new technologies derived from displacement currents for energy and sensors that could greatly influence the future of the world

In the foreseeable future, this tree, which draws on the nutrition of the first equations of physics, will grow stronger and stronger, and it is possible to lead technological innovation and profoundly change human society.

Friction nanogenerators are a disruptive technology with unprecedented output performance and benefits. Compared with classical electromagnetic generators, the high efficiency of friction nanogenerators at low frequencies is unmatched by similar technologies. At the same time, it can also be used as a self-actuated sensor to sense information about static and dynamic processes generated by mechanical triggers. "Friction Nanogenerator" is the first monograph to systematically and comprehensively introduce the four operating modes of friction nanogenerators, as well as the corresponding theoretical models and calculations, device design, and their extensive applications in the recovery of kinetic energy such as human motion, vibration, wind energy, ocean energy, and water flow. The application examples of friction nanogenerators in mobile/wearable/flexible electronic products, biomedical devices, sensor networks, Internet of Things, environmental protection and sensing, infrastructure inspection and blue energy are also systematically introduced. Importantly, Wang recently discovered that the second component of Maxwell's displacement current is the theoretical basis for nanogenerators. Nanogenerators will be another major application of Maxwell displacement current in energy and sensing after electromagnetic wave theory and technology, which has the potential to lead technological innovation and profoundly change human society.