Abstract: The present disclosure relates to a cerium-zirconium-based composite oxide having gradient element distribution and a preparation method therefor. According to the present disclosure, the cerium-zirconium-based composite oxide having gradient element distribution is prepared by a step-by-step precipitation method. First, a zirconium-rich component is precipitated to form a crystal structure and a crystal grain stack structure which have high thermal stability, slow down the segregation of zirconium on a surface after high-temperature treatment, and reduce element migration among crystal grains; second, a cerium-rich component is precipitated to improve the cerium content of the surface layers of the crystal grains, improve the utilization rate of the cerium element, and improve the oxygen storage amount and the oxygen storage rate.

Abstract: The present disclosure provides a cerium-zirconium-based composite oxide with a core-shell structure and a preparation method thereof, a catalyst system using the cerium-zirconium-based composite oxide, a catalytic converter for purifying tail gas by using the catalyst system, and application of the catalyst system or the catalytic converter in motor vehicle exhaust purification, industrial waste gas treatment or catalytic combustion. In the present invention, the cerium-zirconium-based composite oxide with a core-shell structure oxygen storage material is prepared by a step-by-step precipitation method. On the one hand, yttrium and a part of zirconium and cerium are precipitated on a cerium-zirconium surface, where the post-precipitation of yttrium is to segregate yttrium ions (Y3+) on a grain boundary surface, thus reducing lattice surface energy, pinning the grain boundary surface, making the migration of the grain boundary surface difficult, controlling the growth of grains.

Abstract: The invention relates to a nano silicon-carbon composite negative material for lithium ion batteries and a preparation method thereof. A porous electrode composed of silica and carbon is taken as a raw material, and a nano silicon-carbon composite material of carbon-loaded nano silicon is formed by a molten salt electrolysis method in a manner of silica in-situ electrochemical reduction. Silicon and carbon of the material are connected by nano silicon carbide, and are metallurgical-grade combination, so that the electrochemical cycle stability of the nano silicon-carbon composite material is improved.

Abstract: The invention relates to a nano silicon-carbon composite negative material for lithium ion batteries and a preparation method thereof. A porous electrode composed of silica and carbon is taken as a raw material, and a nano silicon-carbon composite material of carbon-loaded nano silicon is formed by a molten salt electrolysis method in a manner of silica in-situ electrochemical reduction. Silicon and carbon of the material are connected by nano silicon carbide, and are metallurgical-grade combination, so that the electrochemical cycle stability of the nano silicon-carbon composite material is improved.

Abstract: An electrochemical method for producing Si nanopowder, Si nanowires and/or Si nanotubes directly from compound SiX or a mixture containing a silicon compound SiX, the method comprises: providing an electrolysis cell having a cathode, an anode and an electrolyte, using the compound SiX or the mixture containing compound SiX as a cathode and immersing the cathode in an electrolyte comprising a metal compound molten salt, applying a potential between the cathode and the anode in the electrolysis cell, and forming one or more of Si nanopowder, Si nanowires and Si nanotubes on the cathode electrode. The method has advantages of: 1) shorter production processing, 2) inexpensive equipment, 3) convenient operation, 4) reduction of contaminate, 5) easily available feed materials, and 6) easy to achieve continuous production. This is a new field of using electrochemical method for producing one-dimensional Si nano material, and a new method of producing Si nanopowder, Si nanowires and Si nanotubes.

Abstract: An electrochemical method for producing Si nanopowder, Si nanowires and/or Si nanotubes directly from compound SiX or a mixture containing a silicon compound SiX, the method comprises: providing an electrolysis cell having a cathode, an anode and an electrolyte, using the compound SiX or the mixture containing compound SiX as a cathode and immersing the cathode in an electrolyte comprising a metal compound molten salt, applying a potential between the cathode and the anode in the electrolysis cell, and forming one or more of Si nanopowder, Si nanowires and Si nanotubes on the cathode electrode. The method has advantages of: 1) shorter production processing, 2) inexpensive equipment, 3) convenient operation, 4) reduction of contaminate, 5) easily available feed materials, and 6) easy to achieve continuous production. This is a new field of using electrochemical method for producing one-dimensional Si nano material, and a new method of producing Si nanopowder, Si nanowires and Si nanotubes.