Energy is the foundation of today's social development and an important indicator of the quality of human life. From the first use of electrical energy, electricity is always transmitted efficiently, safely and accurately through metal wires/cables. As the leading technology of fossil fuel, nuclear energy and hydropower generation, electromagnetic induction power generation technology relies on the flow of free electrons driven by Lorentz force in metal wires. In order to meet the energy requirements of mobile electronic products, Internet of Things and sensor networks, wireless transmission of electrical energy is essential, especially for applications such as implantable medical devices, security, and radio frequency identification. Currently, wireless power transmission techniques are typically based on inductive coils and/or antennas. Compared to wireless communication technologies, wireless charging technology is very important in enhancing the adaptability and mobility of wireless devices and systems. Although there are three wireless charging technology modes of electromagnetic induction, magnetic resonance and radio waves, these technologies are still quite complicated and inefficient. Schematic diagram of wireless power transmission and driving portable and wearable electronic devices based on Maxwell's displacement current Atx Connector,Female Inset Connector,Molding Solder Type Connector,Receptacle Solder Type Connector Shenzhen Hongyian Electronics Co., Ltd. , https://www.hongyiancon.com
In 1861, the British scientist Maxwell proposed the Maxwell equations, the first major equation of physics, and boldly and innovatively introduced the concept of displacement currents in the equations. The Maxwell displacement current is different from the conventionally observed free electron conduction current, but due to the time varying electric field plus the minute movement of the atomic bound charge and the dielectric polarization in the material. The first term of the displacement current unifies the electric and magnetic fields and predicts the existence of electromagnetic waves, laying the physical foundation for wireless communication. The second item of displacement current was found to be the fundamental theoretical basis and source of nano-generators, and has important potential applications in wireless power supply. The theoretical roots of nanogenerators are fundamentally different from traditional electromagnetic generators, which use a variable magnetic field to generate current, using a mechanism of resistive free electron conduction driven by Lorentz force, while nanogenerators use surface polarization charges. The resulting polarization field changes to generate electricity, using a mechanism of capacitive displacement current. Nano-generators are another major application of Maxwell's displacement currents following electromagnetic wave theory and technology in energy and sensing, and will affect the future development of technologies such as the Internet of Things, sensor networks, blue energy and big data.
Recently, Wang Zhonglin, academician of the Chinese Academy of Sciences, chief scientist of the Beijing Institute of Nano-Energy and Systems, Chinese Academy of Sciences, Cao Xia, a professor of Beijing Nano-Energy Institute-Beijing University of Science and Technology, and Wang Ning, a professor at the Beijing University of Science and Technology, conducted a self-distribution based on Maxwell's displacement current. Drive wireless power transmission research. The research team has long been engaged in the research of micro-nano energy and nano-generators. Thanks to the accumulation of research work and the frictional electrification observed in life, the idea of ​​applying Maxwell's displacement current to wireless power transmission is proposed for the first time. A contact sliding rotary generator with a grid structure and a flexible wearable generator are further designed. The external mechanical drive/stimulation causes the polarization charge distribution and the spatial electric displacement field to periodically change with time, thereby generating a displacement current. These generators wirelessly collect mechanical energy from the surrounding environment through the principle of displacement current to continuously power a variety of portable and wearable electronic devices. This wireless power transfer technology provides a more efficient method for energy transfer at low frequencies (<5 Hz). Related research results are published in Advanced Materials. 