2results about How to "Coulombic efficiency is high" patented technology

The present application relates to the technical field of sodium battery materials, in particular to a sodium supplement coating based on a spiral iron-carbon composite material and a preparation method thereof, a spiral polypyrrole template is synthesized by a chiral template method, Fe3C@CNS spiral carbon composite material rich in Fe3C nanocrystals and iron single-atom sites is prepared through iron loading, sulfidation and high-temperature pyrolysis, Na2C2O4@Fe3C@CNS composite material is prepared by highly dispersing sodium oxalate on the surface and in the pores of the spiral carbon composite material through a recrystallization method, finally, a slurry is prepared by mixing the Na2C2O4@Fe3C@CNS composite material with a conductive agent and a binder, and the slurry is coated on the surface of an electrode to form a functional sodium supplement coating. The sodium supplement coating based on the spiral iron-carbon composite material and the preparation method thereof solve the problems of poor interface stability and first-cycle irreversible sodium loss of existing sodium ion batteries, realize efficient sodium pre-activation and interface synergistic regulation, and improve the comprehensive performance of the battery.

The application belongs to the field of battery materials, and discloses a silicon-carbon composite material, a preparation method and application thereof. The silicon-carbon composite material comprises a porous carbon matrix, silicon particles, silicon nanowires and a hard carbon layer. The silicon particles are distributed in the pores of the porous carbon matrix and are bonded to the porous carbon matrix through Si-O-C chemical bonds. The silicon nanowires grow on the surface of the porous carbon matrix, and the surface layer of the silicon nanowires is carburized to form silicon carbide. The hard carbon layer at least coats part of the surface of the particles formed by the porous carbon matrix, the silicon particles and the silicon nanowires. The silicon-carbon composite material provided by the application realizes step-by-step effective regulation of the volume expansion of silicon at the microscale through a multi-stage synergistic mechanism, establishes a radial grading stress management network from the inside of the particles to the surface, and significantly reduces the overall volume expansion rate of the material. The silicon-carbon composite material realizes the synergistic consideration of high specific capacity, low volume expansion, long cycle life and excellent rate characteristics.