CN-116995363-B - Method for preparing alumina lithium porous ceramic diaphragm by taking secondary aluminum ash as raw material

Abstract

The invention relates to a method for preparing a lithium aluminum oxide porous ceramic diaphragm by taking secondary aluminum ash as a raw material, belonging to the field of diaphragm materials. The method takes secondary aluminum ash as a main raw material, and is matched with lithium hydroxide, a pore-forming agent and a doping auxiliary agent, the porous ceramic taking lithium aluminum oxide as a main phase is obtained through compression molding and high-temperature calcination, and then the porous ceramic diaphragm material used for the lithium ion battery is obtained through the hydrothermal surface lithiation of a lithium hydroxide solution. The porous ceramic diaphragm has excellent thermal stability, and thoroughly solves the safety problem of internal short circuit and ignition of the battery caused by shrinkage deformation of the traditional lithium ion battery diaphragm due to heating. The alumina lithium porous ceramic diaphragm has higher porosity and good electrolyte affinity, and meanwhile, the alumina lithium has fast ion conduction characteristic, so that the diaphragm lithium ion transmission efficiency is effectively improved, and the capacity retention rate of the battery in high-current charge and discharge and long-time operation is further improved.

Inventors

• XUE BING
• MA ZIWEN
• MA ZHONGHUA
• WANG HAIYAN
• ZHANG ZHUO
• ZHONG ZHENLIN
• LI YANSONG
• LV SIYU

Assignees

• 吉林大学

Dates

Publication Date

20260508

Application Date

20230803

Claims (2)

1. 1. The method for preparing the lithium aluminum oxide porous ceramic diaphragm by taking the secondary aluminum ash as the raw material is characterized by comprising the following steps of: Mixing secondary aluminum ash, lithium hydroxide, a pore-forming agent and a doping auxiliary agent uniformly according to a certain proportion, carrying out dry molding by using a mold, carrying out vacuum drying for 10 hours at 70 ℃, then raising the temperature to 700-1000 ℃ from room temperature in a muffle furnace at a temperature raising rate of 5-8 ℃ per minute, carrying out heat preservation for 2-5 hours, placing a calcined product in a lithium hydroxide solution of 0.5-3 mol/L, carrying out heat preservation for 4-12 hours in a reaction kettle of 100-140 ℃ to complete the surface lithiation process of the porous material, washing the obtained sample to be neutral by distilled water, and drying for 12 hours at 100 ℃ to obtain the aluminum oxide lithium porous ceramic membrane prepared by taking the secondary aluminum ash as a raw material, wherein the pore-forming agent is one of starch and glucose, the doping auxiliary agent is one of vanadium pentoxide and titanium dioxide, the mass ratio of the secondary aluminum ash, the lithium hydroxide, the pore-forming agent and the doping auxiliary agent is 33-50:25-60:10-23:0.5-2, and the content of aluminum oxide in the secondary ash is more than 85%.
2. 2. A lithium aluminum oxide porous ceramic diaphragm prepared from secondary aluminum ash is characterized by being prepared by the method of claim 1.

Description

Method for preparing alumina lithium porous ceramic diaphragm by taking secondary aluminum ash as raw material Technical Field The invention belongs to the technical field of lithium ion battery diaphragms, and relates to a preparation method of a lithium ion battery diaphragm which is high-temperature resistant and suitable for high-current charge and discharge. Background Lithium ion batteries are widely used in various fields of production and life, and a diaphragm serving as an important component of the lithium ion battery plays a vital role in the safety of the battery. Currently, commercial lithium ion battery separators are mainly porous polyolefin separators, and although polyolefin separators have many advantages for lithium ion batteries, polyolefin separators undergo shrinkage deformation after the temperature exceeds 130 ℃, resulting in short-circuit ignition of the battery. For a large-sized battery used in a large-sized battery energy storage power station matched with wind energy and photovoltaic power generation, the fluctuation of the battery temperature is easier to be caused by larger current charge and discharge, so that the serious safety problem is faced. To solve this problem, researchers have used inorganic particles such as Al 2O3、SiO2、ZrO2 or the like to coat the surface of a polyolefin separator to make a composite separator, and have improved thermal stability of the composite separator by using high heat resistance of the inorganic particles. However, organic materials (polyolefin matrix or organic binder) still exist in the coated separator, and these organic materials still have problems of thermal degradation and thermal shrinkage, resulting in serious safety problems of the battery in overheated environments. For this reason, it has been proposed by the scholars to prepare a pure inorganic separator by a high temperature calcination method using nano Al 2O3、SiO2. Such inorganic separators have incomparable thermal stability, but lower separator porosity, ionic conductivity, and poor electrolyte affinity are detrimental to improvement of battery performance. Therefore, on the basis of keeping the high heat resistance advantage of the inorganic membrane, searching for new raw materials and new methods for preparing the inorganic membrane with high porosity, ion conductivity and electrolyte affinity becomes a new research thought. Aluminum ash is a solid product produced in the process of producing metallic aluminum or aluminum alloy, and consists of metallic aluminum, aluminum oxide and other compounds, and is divided into primary aluminum ash and secondary aluminum ash. Extracting metal aluminum from the primary aluminum ash to obtain secondary aluminum ash. The components of the secondary aluminum ash become more complex due to the use of inorganic salt adjuvants in the process. The metal aluminum and aluminum nitride can generate hydrogen and ammonia when meeting water or being wet, and the comprehensive recycling of aluminum ash is forced to be in the eyebrow. At present, the utilization of the secondary aluminum ash mainly relates to the recovery of aluminum oxide, sodium chloride and potassium chloride from the secondary aluminum ash, and the utilization of the secondary aluminum ash as raw materials for preparing low-added-value products such as building materials, water purifying agents, refractory materials and the like, and the research on the use of the secondary aluminum ash in the preparation of high-added-value products such as lithium ion battery diaphragms has not been reported yet. Disclosure of Invention The invention aims to eliminate potential safety hazard of the battery caused by poor thermal stability of the lithium ion battery diaphragm, improve the capacity retention rate of the battery in high-current charge and discharge and long-time operation, fully utilize various components in the secondary aluminum ash and realize high added value application of solid waste. For this purpose, secondary aluminum ash is used as an important raw material, and is compression molded together with lithium hydroxide, a pore-forming agent and a doping auxiliary agent, and is calcined at a high temperature to form a porous ceramic containing lithium aluminum oxide (LiAlO 2) as a main component. The porous ceramic can be used as a lithium ion battery diaphragm after being subjected to surface treatment of lithium hydroxide. The invention aims at realizing the following technical scheme: Mixing secondary aluminum ash, lithium hydroxide, a pore-forming agent and a doping auxiliary agent uniformly according to a certain proportion, carrying out dry molding by using a mold, carrying out vacuum drying for 10 hours at 70 o C, then heating to 700-1000 o C in a muffle furnace at a heating rate of 5-8 o C/min, carrying out heat preservation for 2-5 hours, placing a calcined product in a lithium hydroxide solution of 0.5-3 mol/L, carrying out heat preservation for 4-12 hours in a