This project belongs to the field of materials science and energy science and technology. Phase change energy storage technology is an effective means to solve the mismatch between energy supply and demand in time and space. It has the advantages of high heat storage density, constant temperature of heat storage and release, and easy process control. It can be widely used in power peak shaving, aerospace, and solar energy. Thermal utilization, waste heat recovery, heating and air conditioning, electronic temperature control and other fields. However, in the actual promotion and application of phase change energy storage technology, many key technical issues are still faced, such as suppression of supercooling of phase change heat storage materials, overcoming phase separation, enhancement of thermal conduction, corrosion protection, phase change heat storage materials and phase change heat storage. Coupling design and heat transfer optimization between the device and heat source. In response to the above-mentioned key technical issues, after years of research and practice accumulation, the project team has innovatively developed a variety of practical modified composite phase change heat storage materials and phase change heat storage devices that can couple clean electricity and solar energy, truly realizing the application of phase change heat storage materials in my country's new energy utilization and clean energy transformation projects. The main innovative achievements of the project are as follows: 1. A new method for preparing composite materials to enhance heat transfer and heterogeneous adsorption nucleation on a micro-scale is proposed, and two practical modified composite phase change heat storage materials have been developed. The project uses micro-scale metal particles and expanded graphite and other means to enhance the heat transfer of phase change materials. At the same time, it uses heterogeneous adsorption to inhibit the nucleation and supercooling of the matrix phase change material, and combines mutual suppression between multiple anions and corrosion inhibitors to control corrosion., effectively overcoming the key problems of single phase change materials such as easy corrosion, easy overcooling, phase separation, and slow heat transfer, and successfully developed two commercially available medium and low-temperature composite phase change heat storage materials. After 3000 charge-and-release cycles, the phase transition temperature remains constant, the phase transition latent heat changes little, the subcooling degree can be as low as 0.8℃~1℃, the thermal conductivity is increased by 2-4 times, and the corrosion weight loss rate is reduced to 0.11%. 2. Based on pulsed heat transfer and tube-fin enhanced heat transfer technology, a series of heat transfer enhanced phase change heat storage devices have been innovatively developed. Based on the pulsed heat pipe enhanced heat transfer technology and the tube-fin heat exchanger enhanced heat transfer technology, the project designed a pulsed heat pipe type phase change heat storage device and a tube-fin type phase change heat storage device respectively. The new heat transfer enhanced phase change energy storage device solves the technical problems of uneven internal heat conduction and low heat conversion efficiency of existing phase change energy storage devices. After testing and analysis, the heat exchange efficiency of the pulsed heat pipe heat transfer type phase change heat storage device can be increased by 27% compared with traditional heat exchange elements, and the heat exchange power of the tube-fin type phase change heat storage device under standard operating conditions can reach 93.4kW. 3. Based on the small temperature difference heat transfer to reduce heat loss and the characteristics of phase change heat storage materials, the phase change heat storage materials and solar collectors are innovatively integrated. The project uses modified composite phase change thermal storage materials as the heat storage medium and vacuum tube solar collectors as the heat collection source, and innovatively designs various forms of integrated phase change thermal storage solar collectors. In addition, based on the theory of thermodynamics and heat transfer, as well as energy analysis and analysis methods, the project studied the thermodynamic problems of vacuum tube collectors, phase change heat storage materials and the heat exchange capacity of fluids in a limited time. The results showed that small temperature difference stepped heat storage devices have obvious advantages in saving heat efficiency. The heat loss of collectors using multi-stage phase change is reduced by 29.7 to 38% compared with traditional single-temperature phase change collectors. The above-mentioned research results have obtained 6 invention patents and 5 utility model patents, and have published 65 papers in domestic and foreign academic journals, of which 35 were included in SCI/EI. The project results have been applied in solar heat storage/heating systems in East China, clean energy alternative heating systems in northern China (Beijing, Hebei, Shandong, etc.), greenhouse vegetable night anti-freezing systems in Xinjiang, and heat storage and peak shaving systems in Hohhot Thermal Power Plant in Inner Mongolia. In the past three years, a total of 735 sets of phase change heat storage devices were sold, 89 heat storage projects were implemented, with an added output value of 72.51 million yuan.