Hydrophobic treatment method of electrode material

Abstract

The invention discloses a hydrophobic treatment method of an electrode material, and belongs to the field of energy materials. Aiming at the problems that the surface activity of battery electrode materials such as ternary materials and silicon is too high and the battery electrode materials are easily subjected to side reaction with moisture, carbon dioxide and the like in the environment, the method comprises the following steps: uniformly coating the battery electrode materials through the adsorption capacity of polysiloxane and the property that a functional group of a polysiloxane body is easy to self-polymerize; the method effectively realizes hydrophobic treatment and passivation of the electrode material, inhibits possible side reactions of the electrode material in storage or slurry preparation and cell preparation processes, prolongs the storage shelf life of the battery electrode material, and reduces the environmental maintenance requirements of a battery production workshop for dehumidification and oxygen control. The method is simple and easy to implement, low in cost, short in consumed time, green, free of pollution and free of waste discharge, and has bright prospects in the fields of production and storage of battery electrode materials and subsequent battery cell processing.

Description

technical field [0001] The invention relates to a hydrophobic treatment method for electrode materials, belonging to the field of energy materials, which can passivate the surface of the electrode material or have a certain hydrophobic ability to improve its surface stability. Background technique [0002] With the rapid growth of the use demand and market scale of lithium-ion batteries, it is urgent to develop lithium-ion battery cathode materials with higher specific discharge capacity and easy production and use to further improve the specific energy of the battery, thereby prolonging the battery and system. Due to its low cost, high specific capacity and good cycle stability, ternary cathode materials have received extensive attention and have been gradually promoted for use. Carbon dioxide has high sensitivity, which puts forward high requirements for the production process of batteries, storage of raw materials, and the maintenance of low-humidity environment in the wo...

AI Technical Summary

Problems solved by technology

Ternary cathode materials have attracted widespread attention and been gradually promoted due to their low cost, high specific capacity and good cycle stability. Carbon dioxide, etc. are highly sensitive, which puts high demands on the production process of batteries, the storage of raw materials, and the maintenance of low-humidity environment in the workshop. Maintaining ultra-low humidity in the processing environment requires a large amount of power consumption, which virtually increases the battery production cost

However, the surface energy of the electrode material will increase sharply during the nanonization process, which will correspondingly increase the chemical activity of the electrode material. At the same time, it is sensitive to oxygen, carbon dioxide, moisture, etc. in the air. The side reaction inhibition of the battery also has an impact

Moreover, after the electrode material is nano-sized, the sharply increased surface energy will make it easier for the negative electrode material to form an oxide layer when it is placed in the air. Since oxides such as silicon and tin have poor conductivity, the oxide layer on the surface will form rapidly. Increase the internal resistance of the battery and affect the performance; the moisture in the air will also be more easily adsorbed on the surface of the nanoparticles and the internal pore structure, and it is difficult to remove it by high-temperature vacuum drying. Hydrogen ions will not only reduce the electrochemical performance, but also induce the overall or local heating of the battery and the decomposition of the electrolyte to produce gas, which will affect the safety of the battery.

In addition, the surface effect of the nanoscale negative electrode material will also cause the electrolyte to more easily interact with the surface of the electrode material during charge and discharge to form an overly thick solid electrolyte interfacial film (SEI), which often means too many active lithium ions It will be consumed, which is very unfavorable for building a lithium-ion battery system with high specific energy

Moreover, too thick SEI will bring higher internal resistance, which will reduce the electron migration of negative electrode materials or promote the diffusion and transport of lithium ions.

Since the electron and ion transport capacity of the silicon-based negative electrode is inherently weak, if the internal resistance is increased due to nanonization, it will directly affect its practical application.

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