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Silicon anode for lithium ion battery and preparation method of silicon anode

A lithium-ion battery, silicon anode technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of complex process and fast battery capacity decay, reduce volume changes, improve initial efficiency, and improve cycle performance. Effect

Pending Publication Date: 2018-08-24
SUZHOU PHYLION BATTERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This scheme uses the special structure of nanotubes to suppress the breakage caused by the expansion and contraction of silicon in the two-dimensional direction, but the overall process is complicated, and, with the increase of charge and discharge times, the capacity of the battery decays faster. At the same time, silicon The material is also in direct contact with the electrolyte

Method used

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  • Silicon anode for lithium ion battery and preparation method of silicon anode
  • Silicon anode for lithium ion battery and preparation method of silicon anode

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Embodiment 1

[0028] Embodiment 1: Copper foil of 6-8 μm is used as a current collector, and a silicon film is formed by chemical vapor deposition or magnetron sputtering coating and deposited on both sides of the copper foil. Through the mask, silicon is isotropically wet-etched with hydrofluoric acid, nitric acid, and acetic acid to form a cylindrical silicon array, and graphene is coated on the silicon surface by using chemical vapor deposition CVD.

[0029] Since the volume change of silicon during charging and discharging is 300%~400%, the maximum available space time between cylinders after expanding 3~4 times is its tangency. Considering that the pole group is extruded in the central axis of the cylinder, the material with a high aspect ratio changes more in the radial direction than in the direction of the central axis. Therefore, it is assumed here that all silicon expands in the radial direction, eliminating the possibility of radial extrusion.

[0030] Such as figure 1 As shown...

Embodiment 2

[0033] 6~8μm copper foil is used as the current collector, and the silicon film is deposited on the front and back sides of the copper foil by chemical vapor deposition or magnetron sputtering coating. Through the mask plate, silicon is anisotropically wet-etched by potassium hydroxide, sodium hydroxide, and ammonia water to form a pyramid-shaped silicon array, and graphene is coated on the silicon surface by using chemical vapor deposition CVD.

[0034] Such as figure 2 , since the area of ​​the regular polygon , where N is the number of sides of the regular polygon, and r is the radius of the inscribed circle. Circular area S of cylindrical cross-section after expansion 2 and the area before expansion S 1 meet S 2 / S 1 =3~4. The distance between the centers of the inscribed circles between regular N-gons on the bottom surface, namely , where a 1 and a 2 are the side lengths of the regular N-gon before and after expansion, r1 and r2 are the inscribed circle radii ...

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Abstract

The invention discloses a silicon anode for a lithium ion battery and a preparation method of the silicon anode. The silicon anode comprises a silicon material arranged in arrays on a substrate, and is characterized in that the surface of the silicon material is coated with a graphene layer. The preparation method of the silicon anode comprises the following steps: forming a silicon film on the front surface and back surface of the substrate with a chemical vapor deposition method or a magnetron sputtering coating method; performing isotropic etching through a mask plate to form the silicon material arranged in arrays; forming the graphene layer applied to the surface of the silicon material with the chemical vapor deposition method. The surface of the silicon array is coated with graphene, so that expansion of silicon can be restrained, conductivity can be improved, direct contact between electrolyte and silicon can be avoided, and the charge and discharge cycle life of the material is prolonged by a good SEI (solid electrolyte interphase) film formed by graphene and electrolyte; first efficiency, cycle performance, the multiplying power performance and the maximum energy densityare improved, and a very good method is provided for commercial application of the silicon-based material.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a negative electrode plate for the lithium ion battery, especially a silicon negative electrode. Background technique [0002] With the increase in the mileage requirements of electric vehicles, the battery system puts forward higher requirements on the energy density of single lithium-ion batteries. For the inside of the battery, positive and negative electrode materials with higher gram capacity are required. Among them, the positive electrode material is transitioning from lithium iron phosphate to ternary, and high nickel in the ternary system has become a trend, while negative electrode materials are based on traditional graphite negative electrode materials, and silicon negative electrode materials have been developed. The development of silicon anodes has gradually become a hot spot in research and development applications. [0003] The discharge capacity of graphite-based anode ...

Claims

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Application Information

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IPC IPC(8): H01M4/134H01M4/1395H01M4/38
CPCH01M4/134H01M4/1395H01M4/386Y02E60/10
Inventor 王永琛朱华君王正伟程凯刘付召
Owner SUZHOU PHYLION BATTERY