Lithium ion battery, negative electrode, negative electrode conductive paste and preparation method of negative electrode conductive paste

[0058] Example 1:

[0059] At room temperature, mix the thickener CMC powder and ultra-pure deionized water at 2:98, and stir in a planetary mixer at 500r/min and 50r/min for 6h at room temperature to obtain a transparent viscous colloidal solution. Add the remaining components in the following proportions, and the mass ratio thickener CMC: active material micron silicon/silicon nitride/graphite (Si:Si 3 N 4 : C = 76.8%: 10.4%: 12.8%): micron silicon/silicon carbide/graphite (Si:SiC:C=70%: 21%: 9%): conductive agent KS-15: binder SBR: elimination Foaming agent EC=1%: 45%: 40%: 3%: 10%: 1%, add active material micron silicon/silicon nitride/graphite and micron silicon/silicon carbide/graphite mixture to rotate 500r/min , Revolve 50r/min and stir at room temperature for 1h. After adding conductive agent KS-15, it will rotate at 500r/min, revolve at 50r/min and stir at room temperature for 1h. After adding binder SBR, it will rotate at 200r/min and revolve at 20r/min for 0.25h at low speed , After adding the defoamer EC, stir at a low speed of 200r/min and revolution 20r/min for 0.3h, make up the required amount of solvent ultrapure deionized water to adjust the solid content to 20%, then rotate 200r/min and revolution 20r/min After stirring at low speed for 2 hours, the solution was in a transparent and black state. At this time, it was observed that there were basically no bubbles in the system. Then the obtained mixed slurry is injected into a vacuum degassing machine to vacuum again to remove residual bubbles to obtain an aqueous negative electrode slurry. According to the conventional production process of lithium-ion button batteries, the aqueous negative electrode slurry is coated on the current collector by a wet film preparation method, and the negative electrode can be obtained after drying and dewatering and oxygen removal. Electrode sheet. Assemble the button half-cell with lithium metal sheet, diaphragm, electrolyte, positive and negative electrode shells, shrapnel, and gasket in the glove box. After standing for 12 hours, a fully infiltrated lithium-ion button half-cell is obtained.

[0060] Example 2:

[0061] At room temperature, the thickener CMC powder and ultra-pure deionized water are mixed at 2:98, and stirred in a planetary mixer at a rotation of 500r/min and a revolution of 50r/min at 50℃ for 2h to obtain a transparent viscous colloidal solution. Add the remaining components in the following proportions in sequence, the mass ratio thickener CMC: active material micron silicon/silicon carbide/graphite (Si:SiC:C=70%:21%:9%): conductive agent SPG-6: viscous Binder LA132: Defoamer PC = 0.5%: 52%: 40%: 3.5%: 3.5%: 0.5%, after adding active material micron silicon/silicon carbide/graphite, the rotation speed is 400r/min and the revolution is 40r/min at normal temperature Stir for 3h, add conductive agent SPG-6, rotate at 400r/min, revolution at 40r/min, and stir at room temperature for 0.5h, add binder LA132, rotate at 150r/min, revolution at 15r/min, stir at low speed for 0.5h, add defoamer After PC, rotate at 150r/min, revolution at 15r/min and stir at low speed for 0.2h, make up the required amount of solvent ultrapure deionized water to adjust the solid content to 10%, then rotate at 100r/min, revolution at 10r/min and stir at low speed for 1.5h The solution was in a transparent and black state. At this time, it was observed that there were basically no bubbles in the system. Then the obtained mixed slurry is injected into a vacuum degassing machine to vacuum again to remove residual bubbles to obtain an aqueous negative electrode slurry. According to the conventional production process of lithium-ion button batteries, the aqueous negative electrode slurry is coated on the current collector by a wet film preparation method, and the negative electrode can be obtained after drying and dewatering and oxygen removal. Electrode sheet. Assemble the button half-cell with lithium metal sheets, separators, electrolyte, positive and negative shells, shrapnel, and gaskets in the glove box. After standing for 12 hours, a fully infiltrated lithium ion button half-cell is obtained.

[0062] Example 3:

[0063] At room temperature, the thickener CMC powder and ultra-pure deionized water are mixed at 2:98, and stirred in a planetary mixer at a rotation of 300r/min and a revolution of 30r/min at 60°C for 3 hours to obtain a transparent viscous colloidal solution. Add the remaining components in the following proportions, and the mass ratio thickener CMC: active material micron silicon/silicon oxide/graphite (Si:SiO:C=75%: 16%: 9%): micron silicon/silicon carbide /Graphite (Si:SiC:C=70%:21%:9%): conductive agent VGCF: SPG-15: binder LA133N: defoamer EC=0.5%: 47%: 47%: 0.5%: 1 %: 3%: 1%, add active material of micron silicon/silicon oxide/graphite and micron silicon/silicon carbide/graphite mixture, rotate 350r/min, revolution 35r/min, stir at room temperature for 2.5h, add conductive agent VGCF After mixing with SPG-15, rotate 500r/min, revolution 50r/min and stir at room temperature for 1h, add binder LA133N, rotate 200r/min, revolution 20r/min, stir at low speed for 0.2h, add defoamer EC and rotate 100r /min, revolution 10r/min low speed stirring 0.4h, make up the required amount of solvent ultrapure deionized water to adjust the solid content to 7.5%, then rotate 100r/min, revolution 10r/min low speed stirring for 1.5h, then the solution will be transparent and black At this time, there are basically no bubbles in the observation system. Then the obtained mixed slurry is injected into a vacuum degassing machine to vacuum again to remove residual bubbles to obtain an aqueous negative electrode slurry. According to the conventional production process of lithium-ion button batteries, the aqueous negative electrode slurry is coated on the current collector through the wet film preparation method, and the negative electrode is obtained by the process of drying and dewatering and oxygen removal. Electrode sheet. Assemble the button half-cell with lithium metal sheets, separators, electrolyte, positive and negative shells, shrapnel, and gaskets in the glove box. After standing for 12 hours, a fully infiltrated lithium ion button half-cell is obtained.