阅读说明：本技术 一种稻壳基硅氧碳复合负极材料的制备方法及其应用 (Preparation method and application of rice hull based silicon-oxygen-carbon composite negative electrode material ) 是由 杨宏训 徐明航 马娇娇 赵象晨 孙孟飞 于 2019-10-17 设计创作，主要内容包括：一种稻壳基硅氧碳复合负极材料的制备方法,将稻壳清洗干净、浸泡于0.1～5mol/L的酸溶液中,在50～80℃下保持8～24h并搅拌,过滤并洗涤至中性干燥,得到产物A；再将产物A平铺于瓷舟中,置于管式炉内,以升温速率为2～5℃/min,温度为400～600℃,时间为0.5～2h进行预碳化处理,得到产物B；然后将产物B与碳材料按照1～6：1～6质量比混合均匀装在球磨罐中,球磨3～12h得到产物C；最后将产物C平铺于瓷舟中,置于管式炉内,以升温速率为2～5℃/min,升温温度为800～1300℃,进行煅烧2～7h,自然冷却后得到稻壳基硅氧碳复合负极材料。本发明工艺简单,原料来源广泛,便于大规模生产。(A preparation method of a rice hull based silicon-oxygen-carbon composite negative electrode material comprises the steps of cleaning rice hulls, soaking the rice hulls in 0.1-5 mol/L acid solution, keeping the rice hulls at 50-80 ℃ for 8-24 hours, stirring, filtering, washing to be neutral and drying to obtain a product A; spreading the product A in a porcelain boat, placing the porcelain boat in a tubular furnace, and carrying out pre-carbonization treatment at the temperature rise rate of 2-5 ℃/min, the temperature of 400-600 ℃ and the time of 0.5-2 h to obtain a product B; and then mixing the product B and a carbon material according to the ratio of 1-6: uniformly mixing the raw materials in a mass ratio of 1-6, putting the mixture into a ball milling tank, and carrying out ball milling for 3-12 h to obtain a product C; and finally, paving the product C in a porcelain boat, placing the porcelain boat in a tubular furnace, calcining for 2-7 h at the temperature rise rate of 2-5 ℃/min and the temperature rise temperature of 800-1300 ℃, and naturally cooling to obtain the rice hull silicon oxy-carbon composite negative electrode material. The invention has simple process, wide raw material source and convenient large-scale production.)

1. A preparation method of a rice hull based silicon-oxygen-carbon composite negative electrode material is characterized by comprising the following steps:

step 1: cleaning rice hulls with ultrapure water, soaking the rice hulls in 0.1-5 mol/L acid solution, keeping the rice hulls at 50-80 ℃ for 8-24 hours while continuously stirring, filtering, washing with ultrapure water until the rice hulls are neutral, and drying to obtain a product A;

step 2: the product A is laid in a porcelain boat and placed in a tubular furnace in inert atmosphere, and pre-carbonization treatment is carried out at the temperature rise rate of 2-5 ℃/min, the pre-carbonization temperature of 400-600 ℃ and the pre-carbonization time of 0.5-2 h to obtain a product B;

and step 3: and mixing the product B with a carbon material according to the ratio of 1-6: uniformly mixing the raw materials in a mass ratio of 1-6, putting the mixture into a ball milling tank, and carrying out ball milling for 3-12 h to obtain a product C;

and 4, step 4: and flatly paving the product C in a porcelain boat, placing the porcelain boat in a tubular furnace in an inert atmosphere, calcining for 2-7 h at the temperature rise rate of 2-5 ℃/min and the temperature rise temperature of 800-1300 ℃, and naturally cooling to obtain the rice hull silicon-oxygen-carbon composite negative electrode material.

2. The preparation method of the rice hull based silicon oxy-carbon composite negative electrode material as claimed in claim 1, characterized in that: the acid solution in the step 1 is any one or a mixture of several of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and oxalic acid in any proportion.

3. The preparation method of the rice hull based silicon oxy-carbon composite negative electrode material as claimed in claim 1, characterized in that: the inert atmosphere in the step 2 is nitrogen or argon or nitrogen-argon mixed gas.

4. The preparation method of the rice hull based silicon oxy-carbon composite negative electrode material as claimed in claim 1, characterized in that: the carbon material in the step 3 is any one or a mixture of a plurality of graphite, asphalt, graphene, conductive carbon black and reduced graphene oxide in any mass ratio.

5. The preparation method of the rice hull based silicon oxy-carbon composite negative electrode material as claimed in claim 1, characterized in that: and 4, the inert atmosphere in the step 4 is any one or a mixture of several gases of nitrogen, argon and hydrogen argon in any mass ratio.

6. The rice hull based silicon-oxygen-carbon composite negative electrode material prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the rice hull based silicon oxy-carbon composite negative electrode material as a negative electrode material of a lithium ion battery.

Technical Field

The invention relates to the field of new energy storage, in particular to a preparation method and application of a rice hull based silicon-oxygen-carbon composite negative electrode material.

Background

Lithium Ion Batteries (LIBs) have the advantages of high energy density, large power density, high working voltage, long cycle life, low self-discharge rate, low environmental pollution and the like, are one of the most effective energy storage devices at present, are widely applied to various fields, and play an increasingly important role in modern society. With the mass production of electric vehicles and the iterative updating of portable electronic devices, there is a higher demand for the capacity and endurance of lithium ion batteries.

However, the mainstream negative electrode material used in the current lithium ion battery in a commercial mode is graphite, the theoretical capacity of the graphite is only 372mAh/g, and the theoretical capacity is close to the theoretical capacity in the practical application process, so that the application requirement of a high-performance battery cannot be met. There has therefore been a great tendency to develop new anode materials with high specific capacity, and among the proposed new anode materials for lithium ion batteries, silicon is considered as the most promising candidate for replacing graphite. It has ultrahigh theoretical capacity (4200mA h/g) which is 11 times of that of graphite, and is rich in earth crust and friendly to environment. However, the silicon material is accompanied by severe volume change (about 300%) during repeated intercalation and deintercalation of lithium ions, resulting in pulverization of silicon particles, electrode exfoliation, and excessive growth of Solid Electrolyte Interface (SEI) during charge and discharge, which affect the cycle life thereof. In order to solve this drawback, a silicon-oxygen-carbon composite anode material is a big hot spot in the research. The carbon material has high electrical conductivity, relatively firm structure and small volume expansion, usually less than 10%, in the circulation process, and also has good flexibility and lubricity, and can inhibit the volume expansion of the silicon material in the circulation process to a certain extent. At present, most of the processes for preparing the silicon-oxygen-carbon cathode material are complex and have high cost. Therefore, it is still a challenge to develop a preparation method that is simple in process, low in cost, and capable of effectively suppressing the volume expansion of silicon particles.

It has been demonstrated that a wide variety of functional nanostructured materials can be produced from natural biomass. Among various natural substances, rice is one of the most common crops and is widely planted in the world, rice hulls are used as agricultural waste, and the common treatment mode is open-air incineration, so that not only is resource waste caused, but also the environment is polluted. The detection proves that the rice hulls contain rich carbon and silicon elements (the rice hulls contain 20 weight percent of silicon dioxide), and can be used as the lithium ion battery cathode material through design and manufacture, so that the rice hulls become important resources for developing novel silicon-oxygen-carbon composite electrode materials, and the rice hulls have important significance for solving the problems of energy crisis and environmental pollution at present.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method and application of a rice hull based silicon-oxygen-carbon composite negative electrode material.

The invention adopts natural renewable crop waste rice hulls as precursors of the cathode material, and prepares the lithium ion battery cathode material with high cycle stability and low cost by a simple mechanochemical method.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a preparation method and application of a rice hull based silicon-oxygen-carbon composite negative electrode material comprise the following steps:

step 1: cleaning rice hulls with ultrapure water, soaking the rice hulls in 0.1-5 mol/L acid solution, keeping the rice hulls at 50-80 ℃ for 8-24 hours while continuously stirring, filtering, washing with ultrapure water until the rice hulls are neutral, and drying to obtain a product A;

step 2: the product A is laid in a porcelain boat and placed in a tubular furnace in inert atmosphere, and pre-carbonization treatment is carried out at the temperature rise rate of 2-5 ℃/min, the pre-carbonization temperature of 400-600 ℃ and the pre-carbonization time of 0.5-2 h to obtain a product B;

and step 3: and mixing the product B with a carbon material according to the ratio of 1-6: uniformly mixing the raw materials in a mass ratio of 1-6, putting the mixture into a ball milling tank, and carrying out ball milling for 3-12 h to obtain a product C;

and 4, step 4: and flatly paving the product C in a porcelain boat, placing the porcelain boat in a tubular furnace in an inert atmosphere, calcining for 2-7 h at the temperature rise rate of 2-5 ℃/min and the temperature rise temperature of 800-1300 ℃, and naturally cooling to obtain the rice hull silicon-oxygen-carbon composite negative electrode material.

Further preferably, the acid solution in step 1 is any one or a mixture of several of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and oxalic acid in any proportion.

Further preferably, the inert atmosphere in step 2 is nitrogen or argon or a nitrogen-argon mixture.

Further preferably, the carbon material in step 3 is any one or a mixture of several of graphite, pitch, graphene and reduced graphene oxide in any mass ratio.

Further preferably, the inert atmosphere in the step 4 is any one or a mixture of several of nitrogen, argon and hydrogen-argon in any mass ratio.

The rice hull based silicon-oxygen-carbon composite negative electrode material prepared by the preparation method according to any one of claims 1 to 5.

An application of a rice hull based silicon-oxygen-carbon composite negative electrode material as a negative electrode material of a lithium ion battery.

The invention has the advantages that:

1. the preparation method of the rice hull based silicon-oxygen-carbon composite negative electrode material directly takes the rice hull which is a byproduct of rice as a raw material, realizes the reutilization of waste crops, is beneficial to protecting the environment, reduces the production cost, meets the national requirement for vigorously developing new materials of natural waste biomass, and improves the economic, social and ecological benefits of rice;

2. the rice hull based silicon-oxygen-carbon composite negative electrode material is prepared by reducing silicon dioxide into a silicon-oxygen compound by a simple and easy-to-operate reduction means based on natural silicon dioxide components contained in rice hulls, and mechanically mixing the silicon-oxygen-carbon composite negative electrode material with a carbon material to generate SiO with a compact carbon coating layer_xThe @ G composite negative electrode material effectively improves the conductivity of the silicon-oxygen-carbon material and inhibits the volume expansion of silicon particles, thereby improving the cycle performance of the battery.

Drawings

Fig. 1 is a scanning electron microscope image of the rice hull based silicon oxy-carbon composite negative electrode material prepared in example 1 of the present invention.

Fig. 2 is an X-ray diffraction (XRD) pattern of the rice hull based silicon oxycarbon composite negative electrode material prepared in example 1 of the present invention.

FIG. 3 is a BET diagram of the rice hull based silicon oxy-carbon composite negative electrode material prepared in example 1 of the present invention.

FIG. 4 shows that the rice husk based silicon oxy-carbon composite negative electrode material prepared in example 1 of the invention is used as a negative electrode material of a lithium ion battery at 500mA g^-1Cycle performance graph below.

Detailed Description

The following examples are presented to enable one of ordinary skill in the art to more fully understand the present invention and are not intended to limit the scope of the embodiments described herein.