5results about How to "Small volume expansion" patented technology

A negative electrode for an electrochemical device and an electrochemical device including the same are provided. The negative electrode for the electrochemical device comprises: a current collector; and a negative electrode active material layer present on the current collector, wherein the negative electrode active material layer comprises particles containing a silicon-based active material, a linearly conductive material, and a binder for the particles, wherein the dispersion of the particles within the negative electrode active material layer is 1 × 10⁻⁶. ‑2 Up to 10×10 ‑2 The standard deviation of particle dispersion is 1×10⁻⁶. ‑3 Up to 4×10 ‑3 The volume expansion rate of the negative electrode active material layer is 3% to 30%.

This application relates to the field of battery technology, specifically to battery cells, battery devices, energy storage devices, and power consumption devices. In the negative electrode sheet of a battery cell, the negative electrode active layer includes a first active layer and a second active layer. The second active layer is disposed between the first active layer and the negative electrode current collector. The first active layer contains a first negative electrode active material, and the second active layer contains a second negative electrode active material. The sphericity of the first and second negative electrode active materials is independently 0.7~0.9, and their roundness is independently 0.42~0.65, respectively. Furthermore, the sphericity and / or roundness of the first negative electrode active material is greater than that of the second negative electrode active material. This application can improve the irreversible thickness growth of the negative electrode sheet during cycling and enhance kinetics, thereby helping to reduce the volume expansion of the cell throughout its life cycle while maintaining fast-charging performance.

The application discloses a kind of negative electrode material and its preparation method and application, negative electrode material includes: porous Si C, silicon nanometer layer and carbon nanometer layer;Wherein, the layer number of silicon nanometer layer is greater than or equal to 1, the layer number of carbon nanometer layer is greater than or equal to 1;Negative electrode material uses porous Si C as framework, silicon nanometer layer and carbon nanometer layer are spaced distribution in the pore of porous Si C;The pore size of the pore of porous S i C is between 1nm-500nm;The thickness of silicon nanometer layer is between 1nm-50nm;The thickness of carbon nanometer layer is between 1nm-50nm;Lithium battery prepared by using the negative electrode material provided in the embodiment of the application has lower volume expansion rate, higher mass specific capacity, good conductivity and cycle life.

The application discloses a negative electrode binder and a preparation method thereof, a pole piece and a battery, wherein a neutral chitosan solution and a PMMA emulsion are added into a PAALi emulsion, and are fully stirred and uniformly distributed to obtain the negative electrode binder. Through the synergistic compounding of the PAALi, the neutral chitosan and the PMMA, a modified silicon-carbon negative electrode binder is prepared, and the problems of cycle pulverization and capacity attenuation of a silicon-based negative electrode are effectively solved. The binder has the functions of dynamic elastic buffering, strong interface fixing and artificial protective layer, significantly improves the structural stability and cycle life of the pole piece, and is simple in preparation process, controllable in cost, convenient for large-scale production and suitable for the field of high-end new energy batteries.

The present application relates to a kind of porous carbon microspheres preparation method, porous carbon microspheres and its application, preparation method includes: water glass powder is mixed with water and stirred uniformly to obtain water glass solution, remove metal cation in water glass solution by cation exchange resin bed layer to obtain active silicic acid aqueous solution, using alkaline solution to adjust the pH value of active silicic acid aqueous solution to neutral, then react for a certain time at a certain temperature, obtain silica-containing silica sol, silica sol is mixed with carbon source material and is evenly sprayed dry, carbonization treatment obtains carbon microsphere powder material, then etching, washing, drying are sequentially carried out, remove silica, obtain porous carbon microspheres;The porous carbon microspheres of the present application can be used as carbon matrix to prepare silicon-carbon composite negative material, reduce the volume expansion of silicon, use the silicon-carbon composite negative material to prepare negative electrode sheet and assemble into lithium ion battery, can improve the first coulomb efficiency, rate performance and cycle stability of battery.