39results about How to "Lower diffusion barrier" patented technology

The invention relates to the field of materials science, particularly a stanene material, a preparation method thereof and a battery employing the stanene material. The stanene material comprises at least one layer of atomic structure. A plurality of holes are distributed in the atomic structure. The holes are formed by removing atoms. A relationship between the number n of the atoms removed fromeach hole and the occupied layer number r is n=6r<2>.

The invention relates to a pressureless sintering boron carbide ceramic preparation method of using more than 2 microns of coarse-grained powder as a raw material. The preparation method comprises the following steps: putting 70-80 wt% of boron carbide (D50 is greater than or equal to 2 microns), 4-8 wt% of powdered carbon, 0.7-2 wt% of yttrium oxide powder and the balance a binder and a dispersant into a mixing container of a ball mill, adding deionized water and ball-milling for pulping so as to obtain slurry with solid content being 25-45 wt%; preparing granulation powder from the slurry by using a spray drying granulating machine; pressing the granulation powder at 100-200 MPa by a dry pressing or isostatic cool pressing process to generate a green body; and putting the green body into a vacuum furnace, and carrying out thermal insulation at 200-2300 DEG C for 0.5-5h to finish sintering by a vacuum or pressureless sintering mode so as to obtain boron carbide ceramic. As the low-cost coarse-grained boron carbide powder is used as the raw material, manufacturing cost of the boron carbide ceramic can be reduced greatly by the pressureless sintering process for large-scale production. The boron carbide ceramic is suitable for fields of nuclear power, semiconductor equipment, armor protection and the like.

The invention provides a composite positive electrode active material and a lithium ion secondary battery. The composite positive electrode active material comprises positive electrode active material particles, and a coating material which is positioned on the external of the positive electrode active material particles for coating the positive electrode active material particles. The positive electrode active material particles are layered lithium composite oxide; the general formula of the layered lithium composite oxide is Li1+xNiaCobM (1-a-b)Y2, wherein x is greater than or equal to minus 0.1 and less than or equal to 0.2; a is greater than or equal to 0 and less than or equal to 1, b is greater than or equal to 0.05 and less than or equal to 1, and a+b is greater than or equal to 0.05 and less than or equal to 1; M is selected from one or more of Mg, Zn, Ga, Ba, Al, Fe, Cr, Sn, V, Mn, Sc, Ti, Nb, Mo or Zr; Y is selected from one or more of O, or F; the bulk structure of the coating material is P4 / mbm space group; and the lithium ion secondary battery comprises the composite positive electrode active material. The lithium ion secondary battery is higher in energy density and better in cycle performance under high voltage.