TWI458164B - Method for making electrode material of lithium-ion battery - Google Patents

Description

Method for preparing lithium battery electrode material

The invention relates to a preparation method of a lithium battery electrode material, in particular to a preparation method of a lithium titanate electrode material.

In recent years, spinel lithium titanate (Li ₄ Ti ₅ O ₁₂ ) has received increasing attention as an electrode material for new energy storage batteries because of the crystal of spinel lithium titanate during lithium ion intercalation-deintercalation. The structure can maintain a high degree of stability. The lithium ion is a spinel structure before and after embedding, and the lattice constant changes little, and the volume change is small. Therefore, lithium titanate is called a "zero strain" electrode material. This can avoid the destruction of the structure due to the back and forth expansion of the electrode material in the charge and discharge cycle, thereby improving the cycle performance and the service life of the electrode, and reducing the attenuation of the specific capacity amplitude as the number of cycles increases, so that the lithium titanate Excellent cycle performance. However, the lithium titanate material itself has a lower electrical conductivity, a lower rate performance, and a lower tap density than a material such as lithium manganate.

In order to solve this problem, the commonly used methods are: preparing nano-titanium titanate particles to reduce the lithium ion diffusion path, increasing the surface area of the electrochemical reaction; mixing more conductive carbon materials between the lithium titanate powders; Doping and the like. Xu Ning et al., in the publication of Chinese Patent Application Publication No. CN101378119, published on March 4, 2009, discloses a method for preparing a carbon-coated composite lithium titanate, which is specifically: a volume ratio of lithium salt and titanium dioxide is mixed, a dispersing agent is added to the mixture and thoroughly mixed by ball milling, and then the ball-milled product is vacuum-dried to obtain a precursor; the precursor is prepared to be baked at a temperature for a fixed time. Lithium titanate is prepared; a carbon source material is coated on the surface of the prepared lithium titanate by immersion evaporation; the lithium titanate coated with the carbon source material is heat-treated to obtain a carbon-coated composite titanic acid. lithium. The preparation method directly forms chemically coated carbon on the surface of the lithium titanate by pyrolysis reaction of the carbon coating material, and the coated carbon is more firmly and tightly contacted with the surface of the lithium titanate material, thereby greatly improving the electronic conductivity of the material. , effectively improve the material's rate of charge and discharge performance.

However, the above method uses a ball milling method to mix the lithium salt and the titanium dioxide solid phase to form a precursor, and the precursor is only a uniform mixture of the two raw material powders, thereby causing the appearance of the carbon-coated composite lithium titanate of the final product. Irregular, the particle size distribution is uneven, and the tap density is low, and the fluidity and workability are poor.

In view of the above, it is necessary to provide a method for preparing a lithium battery electrode material, and a spherical particle of a lithium titanate electrode material having a regular morphology, a uniform particle size distribution, and a high tap density can be obtained by the preparation method.

A method for preparing a lithium battery electrode material, comprising: providing a lithium source solution and a titanium source particle, wherein the lithium source solution and the titanium source particle have a molar ratio of lithium element to titanium element of 4:5 to 4.5:5. Mixing uniformly to prepare a sol; providing a carbon source compound, uniformly mixing the sol with the carbon source compound to form a mixed sol; spray drying the mixed sol to obtain precursor particles; and heat treating the precursor particles to obtain Lithium battery electrode material.

A method for preparing a lithium battery electrode material, comprising: providing a lithium source solution and a a titanium source particle, the lithium source solution and the titanium source particles are uniformly mixed in a molar ratio of lithium element to titanium element of 4:5 to 4.5:5 to prepare a sol; spray drying the sol to obtain a plurality of precursor particles; Heat treating the precursor particles to prepare a plurality of secondary lithium titanate particles; providing a carbon source compound solution, uniformly dispersing the obtained plurality of secondary lithium titanate particles in the carbon source compound solution to form a mixed solution The solvent in the mixed solution is removed, and the carbon source compound is cleaved to obtain a composite lithium titanate electrode material.

A method for preparing a lithium battery electrode material, comprising: providing a lithium source solution and a titanium source particle, wherein the lithium source solution and the titanium source particle have a molar ratio of lithium element to titanium element of 4:5 to 4.5:5. The mixture is uniformly mixed to obtain a sol; the above sol is spray-dried to obtain a plurality of precursor particles; and the precursor particles are heat-treated to prepare a plurality of lithium secondary lithium titanate particles.

Compared with the prior art, the method obtains a sol by liquid-solid mixing, and obtains precursor particles by spray drying. The precursor particles are spherical, have a small specific surface area, a small particle size, a uniform particle size distribution and a relatively good particle morphology. The characteristics of the rules and the like, so that the finally obtained lithium titanate electrode material has a higher tap density, better fluidity and workability.

10‧‧‧Composite lithium titanate electrode material

100,200‧‧‧ precursor particles

102,202‧‧‧Lithium hydroxide particles

104,204‧‧‧Titanium dioxide particles

106‧‧‧Sucrose granules

108‧‧‧Lithium titanate particles

110‧‧‧carbon layer

1 is a flow chart showing a method of preparing a lithium battery electrode material according to a first embodiment of the present invention.

2 is a schematic view showing the structure of a precursor particle prepared in the first embodiment of the present invention.

3 is a schematic view showing the structure of a composite lithium titanate electrode material prepared according to a first embodiment of the present invention.

4 is a negative composite lithium titanate electrode material prepared by using the first embodiment of the present invention. The specific capacity test curve of the first charge and discharge of the battery at different magnifications.

Fig. 5 is a graph showing the cycle performance test of a battery using a composite lithium titanate electrode material prepared by the first embodiment of the present invention as a negative electrode at different magnifications.

6 is a flow chart showing a method of preparing a lithium battery electrode material according to a second embodiment of the present invention.

Figure 7 is a schematic view showing the structure of a precursor particle prepared in accordance with a second embodiment of the present invention.

Hereinafter, a method for preparing a lithium battery electrode material according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1 , FIG. 2 and FIG. 3 , a first embodiment of the present invention provides a method for preparing a composite lithium titanate electrode material. The method comprises the following steps: Step 1: providing a lithium source solution and a titanium source particle, the lithium source solution and the titanium source particle having a lithium element to titanium element molar ratio (Li:Ti) of 4:5 to 4.5:5 a ratio of uniformly mixing to obtain a sol; a second step, providing a carbon source compound, uniformly mixing the sol with the carbon source compound to form a mixed sol; and step 3, spray drying the mixed sol to obtain precursor particles 100; 4. The precursor particles 100 are heat-treated to obtain a composite lithium titanate electrode material 10.

The above steps will be specifically described below.

In the first step, the lithium source solution is formed by dissolving a lithium salt or lithium hydroxide (Li(OH)) in a solvent. The lithium salt may be lithium carbonate, lithium sulfate, lithium nitrate or chlorination Lithium, etc., and is not limited to the ones listed. The solvent may be water, ethanol or acetone or the like. The lithium salt is preferably a water-soluble lithium salt, the solvent is preferably water, and the water is preferably deionized water or distilled water to avoid introduction of other impurity elements.

The titanium source particles are insoluble in the solvent, and the titanium source particles have a particle size ranging from 20 nm to 100 μm, preferably from 50 nm to 50 μm. The smaller the particle diameter of the titanium source particles, the more favorable it is to form a uniform sol. The titanium source particles may be water-insoluble titanium oxide (TiO ₂ ) particles, hydrated titanium oxide (TiO ₂ ‧ x H ₂ O) particles, or titanium oxyhydroxide (TiO(OH) ₂ ) particles. If the titanium source particles are titanium oxyhydroxide particles, the hydroxy titanium oxide particles may be prepared by: providing a soluble titanium salt and ammonia water, and adding the ammonia water to the titanium salt, thereby making the ammonia water and the titanium The salt reacts to form a precipitate of titanium oxyhydroxide; and the precipitate of titanium oxyhydroxide is washed with water. The above method can continuously obtain a titanium hydroxide particle having a small particle diameter by continuously stirring while reacting. The soluble titanium salt may be titanium tetrachloride (TiCl ₄ ) or titanyl sulfate (TiOSO ₄ ), etc., and the amount of the ammonia added is determined by precipitating all of the titanium in the soluble titanium salt, and may be appropriately excessive. The purpose of washing the titanium oxyhydroxide precipitate is to wash away some residual ions, such as chloride ions (Cl ^- ), sulfate ions (SO ₄ ^2- ), etc., thereby preventing the residual ions from affecting the finally obtained composite lithium titanate electrode. The electrochemical properties of the material.

In this embodiment, the lithium source solution is an aqueous solution of lithium hydroxide of 0.5 mol/L to 3 mol/L, and the titanium source particles are weighed according to a molar ratio of lithium element to titanium element of 4:5. Titanium dioxide particles of rice particle size.

In order to form a uniform sol, the above mixture formed by the lithium hydroxide solution and the titanium dioxide particles may be further stirred. The specific manner of the stirring is not limited, and may be mechanical stirring, magnetic stirring or ultrasonic dispersion.

In the second step, the amount of the carbon source compound may be a molar ratio of carbon element to titanium element. (C: Ti) is provided in a ratio of 0.1:1 to 2:1, and the carbon source compound is preferably a reducing organic compound which is soluble in a solvent in the above lithium source solution, and such an organic compound can be cleaved into carbon. The carbon source compound may be sucrose, glucose, phenolic resin, polyacrylic acid, polyacrylonitrile, polyethylene glycol or polyvinyl alcohol. In this embodiment, the carbon source compound is sucrose.

In addition, the step may further add a surface modifier to the mixed sol, the surface modifier has a mass of 0.01% to 0.1% of the mass of the carbon source compound to be added, and the surface modifier is a water. An oil-in-water emulsifier which can surface-modify the titanium source particles contained in the sol, thereby uniformly mixing the titanium source particles, the lithium salt or lithium hydroxide, and the added carbon source compound. Preferably, the surface modifier may be Tween 80 or Siban 80 or the like.

Further, in order to uniformly disperse the carbon source compound in the sol, the carbon source compound may be further dispersed by means of high-speed stirring or ultrasonic dispersion. Through the liquid-solid mixing method of the above steps 1 and 2, the carbon source compound, the lithium salt or the lithium hydroxide and the titanium source particles in the mixed sol can be uniformly mixed.

In the third step, the mixed sol is spray-dried by a gas flow spray dryer having an atomizing device using a dual-flow nozzle, which is dried by cocurrent drying. .

Specifically, the sol is fed into the airflow spray dryer by a peristaltic pump at a feed rate of 5 to 40 mL/min, and the feed rate is preferably 10 to 20 ml/ Using the two-flow nozzle atomizing device to atomize the sol at a pressure of about 0.05 MPa to 0.2 MPa to form a mist-like droplet, in this embodiment, the gas pressure during the atomization process is 0.1 MPa; The formed mist droplets are cocurrent with the hot air, and in the hot air, the mist droplets are instantaneously evaporated. The entire solvent is formed to form a plurality of porous spherical precursor particles. In the whole process, the temperature of the hot air is controlled to be about 200 ° C ~ 400 ° C when the feed is formed, the temperature of the air after the spherical precursor particles are formed is about 50 ° C ~ 150 ° C, and after forming the spherical precursor particles, the spray The air in the dryer is vented through a first-order vortex. In this embodiment, the temperature of the hot air at the time of feeding is 300 ° C, and the temperature of the air after forming the spherical precursor particles is 100 ° C.

The spray drying method can disperse the mixed sol into extremely fine mist droplets, so that the atomized mixed sol has a large specific surface area, and the mist droplets generate intense heat exchange with hot air. Thereafter, the solvent in the mist droplets is quickly removed in a few seconds to several tens of seconds to obtain a porous spherical or spheroidal precursor particle having a particle diameter of 1 μm to 10 μm. The precursor particles have the advantages of relatively uniform particle size distribution, good fluidity, good processability and regular morphology. Referring to FIG. 2, in the present embodiment, each of the precursor particles 100 includes a plurality of titanium dioxide particles 104, and each of the titanium dioxide particles 104 is uniformly coated with lithium hydroxide particles 102 and sucrose particles 106, and the plurality of titanium oxide particles 104 are uniformly coated. There are pores between them such that each of the precursor particles 100 is a porous spherical structure.

In the fourth step, the heat treatment is specifically carried out by heating the plurality of porous precursor particles 100 at a temperature of 400 ° C to 1000 ° C for about 2 to 40 hours under an inert gas atmosphere. In this embodiment, the heat treatment temperature was 700 ° C, and the heat treatment time was 16 hours. Referring to FIG. 3, during the heat treatment, the titanium dioxide particles 104 and the lithium hydroxide particles 102 in the plurality of porous precursor particles 100 are reacted to form a plurality of lithium nanotitanate particles 108, and at the same time, the sucrose particles thereof 106 is cracked to form a carbon layer 110 coated on the surface of the nano titanium titanate particles 108 to form a composite lithium titanate having substantially the same spherical morphology as the precursor particles 100. Electrode material 10. Specifically, during the heat treatment, the sucrose particles 106 will remove the hydrogen and oxygen elements therein and only the carbon elements remain, and the carbon element is adsorbed to the lithium titanate under the action of surface tension in the process. On the surface of the particles 108, the carbon layer 110 can inhibit the growth of the lithium titanate crystal grains. In addition, since the regular spherical porous precursor particles 100 can be obtained by the above-described spray drying method, the precursor particles 100 have a plurality of heat transfer passages formed by the pores, so that the titanium oxide particles 104 and the lithium hydroxide particles The 102 can be reacted to form lithium titanate particles 108 in a relatively short period of time at a lower heat treatment temperature.

Since the composite lithium titanate electrode material 10 is obtained by the spherical precursor particles 100, it also has a spherical particle morphology, and the spherical composite lithium titanate electrode material 10 has a uniform particle size distribution and a small diameter, thereby having a comparative High vibration density, good fluidity and processing properties. The spherical composite lithium titanate electrode material 10 has a large amount of lithium titanate particles 108 inside and a carbon layer 110 coated on the surface of the lithium titanate particles 108. The composite lithium titanate electrode material 10 was tested to have a tap density of 1.62 g/cm ³ . At the same time, the composite lithium titanate electrode material 10 was used as a negative electrode material for battery performance test, and the composite lithium titanate electrode material 10 was found to have better charge and discharge capacity and cycle performance. Referring to FIG. 4, the first time charging and discharging performance of the composite lithium titanate electrode material 10 at different magnifications is quantitatively determined. The specific capacity of the battery can reach about 170 millimeters when the current ratio is 0.1C. Ampere time / gram; at a rate of 1 C, the specific capacity of the battery can reach about 160 mAh / gram; at a rate of 2 C, the specific capacity of the battery can still reach about 150 mA / gram. Referring to FIG. 5, in this embodiment, the cycle performance of the composite lithium titanate electrode material 10 at different magnifications is quantitatively determined. It can be seen that under the conditions of current magnifications of 0.1 C, 1 C and 2 C, respectively, with the number of cycles The increase in the specific capacity of the battery is small.

Referring to FIG. 6, a second embodiment of the present invention provides a method for preparing a lithium titanate electrode material. The method includes the following steps:

Step one, providing a lithium source solution and a titanium source particle, the lithium source solution and the titanium source particles are uniformly mixed in a molar ratio of lithium element to titanium element of 4:5 to 4.5:5 to obtain a sol;

Step two, spray drying the above sol to obtain a plurality of precursor particles;

In the third step, the precursor particles are heat-treated to prepare a plurality of lithium secondary lithium titanate particles.

Step four, providing a carbon source compound solution, uniformly dispersing the obtained plurality of secondary lithium titanate particles in the carbon source compound solution to form a mixed solution;

In step five, the solvent in the mixed solution is removed, and the carbon source compound is cleaved to obtain the composite lithium titanate electrode material.

The difference between this embodiment and the above first embodiment is that the first embodiment is obtained by first mixing the sol with a carbon source compound, then obtaining the precursor particles by spray drying, and finally obtaining a composite by heat treatment or the like. The titanate acid electrode material; in this embodiment, the precursor particles are obtained by first spraying the sol by spray drying and heat-treating the plurality of precursor particles to obtain a plurality of secondary lithium titanate particles, and then the plurality of The lithium titanate particles are mixed with the carbon source compound solution, and finally the composite titanate electrode material is obtained by a process such as cracking a carbon source compound. The respective steps of the embodiment will be described in detail below.

Referring to FIG. 7, the second step in the embodiment is substantially the same as the method of the third step of the spray drying in the above embodiment, except that the first embodiment is spray-dryed by uniformly mixing the sol and the carbon source compound. Mixed sol, and this embodiment The sol is directly spray-dried, and each of the precursor particles 200 obtained by the spray drying method in the present embodiment includes a plurality of titanium dioxide particles 204 uniformly coated with a plurality of lithium hydroxide particles 202 on the surface of each of the titanium dioxide particles 204. . There are pores between the plurality of titanium dioxide particles 204 in each of the precursor particles 200 such that each of the precursor particles 200 has a porous spherical structure. Further, the process parameters of the spray drying in this embodiment are substantially the same as those of the first embodiment.

In the third step, the heat treatment is specifically carried out by heating the precursor particles 200 at 100 ° C to 1000 ° C for 1 hour to 20 hours under an inert gas atmosphere. In this embodiment, the heat treatment heating temperature is 700 ° C, and the heating time is 10 hours. During the heat treatment, the plurality of titanium dioxide particles 204 and the plurality of lithium hydroxide particles 202 in each of the precursor particles 200 are reacted to form The nano titanium titanate particles are formed to form secondary lithium titanate particles, and the morphology of the secondary lithium titanate particles is substantially the same as that of the precursor particles 200, that is, a porous spherical structure. Specifically, each of the secondary lithium titanate particles includes a plurality of nano-titanate particles, and a plurality of pores are present between the plurality of nano-titanium titanate particles. The secondary lithium titanate particles can be directly used as an electrode active material.

In the fourth step, the carbon source compound solution includes a solvent and a carbon source compound dissolved in the solvent, and the carbon source compound is preferably a water-soluble reducing organic compound, and the organic compound can be cleaved into carbon. The organic compound may be sucrose, glucose, phenolic resin, polyacrylic acid, polyacrylonitrile, polyethylene glycol or polyvinyl alcohol. In this embodiment, the carbon source compound is sucrose, wherein the ratio of the sucrose is provided in a ratio of a molar ratio of carbon element to titanium element of 0.1:1 to 2:1. The solvent for dissolving the carbon source compound may be water, ethanol, propanol, acetone or N-methylpyrrolidone. In the present embodiment, the solvent is water. Due to each of the secondary lithium titanate particles The plurality of lithium titanate particles are included, and the plurality of lithium titanate particles include a plurality of pores. Therefore, the carbon source compound solution may coat each of the lithium titanate particles. In addition, the concentration of the carbon source compound solution is not too large, and if the value is too large, the secondary lithium titanate particles are not easily dispersed uniformly in the carbon source compound solution, and the carbon source compound is wasted, and at the same time, the viscosity is too Large, resulting in poor fluidity of the carbon source compound, does not sufficiently flow through the pores in each of the secondary lithium titanate particles, so that the surface of each of the secondary lithium titanate particles cannot be sufficiently coated. The concentration of the carbon source compound solution is not too small. If the concentration of the carbon source compound solution is too small, the viscosity of the carbon source compound solution is too small, so that the carbon formed by the carbon source compound after being cleaved in the step 5 is not easily coated on the secondary titanic acid. The surface of the lithium titanate particles in the lithium particles. The concentration of the carbon source compound solution is preferably from 10% to 40%. In the present embodiment, the concentration of the carbon source compound solution is 15%.

Further, in order to uniformly disperse the secondary lithium titanate particles in the carbon source compound solution, a surfactant may be further added, which may modify the surface of the secondary lithium titanate particles, thereby The secondary lithium titanate particles are uniformly dispersed in the carbon source compound solution. The surfactant is preferably Tween 80, Siban 80 or the like. Additionally, the step may further include agitating the solution of the carbon source compound in which the lithium titanate particles are dispersed, thereby uniformly mixing the spherical precursor particles with the carbon source compound solution. The stirring method is not limited and may be ultrasonic dispersion or high speed stirring.

In the fifth step, the mixed liquid may be first dried, and the specific manner of drying the mixed liquid may be drying, water bath or oil bath heating or the like. Wherein the heating temperature needs to be less than 200 degrees. In the drying process, as the moisture evaporates, the carbon source compound adsorbs to the surface of each of the lithium titanate particles.

The method of cracking the carbon source compound is as follows: in an inert gas atmosphere, at 400 The plurality of carbon source compound-coated secondary lithium titanate particles are heat-treated at a temperature of from ° C to 1000 ° C for 4 to 20 hours. In this embodiment, the heat treatment temperature is 700 ° C, and the heat treatment time is 6 hours. During the heat treatment, the carbon source compound distributed in the above secondary lithium titanate particles is decomposed and carbonized to form a surface of the titanic acid particles coated with the carbon layer in each of the secondary lithium titanate particles. Thereby forming a composite lithium titanate electrode material.

In the embodiment of the present invention, a uniform sol is obtained by liquid-solid mixing, and precursor particles are obtained by spray drying. Compared with the solid-solid mixing, the sol is formed by the solid-liquid mixing, so that the titanium source particles, the lithium source solution and the carbon source compound can be more uniformly atomically mixed, so that the finally obtained composite lithium titanate battery can be obtained. In the polar material, the carbon layer can be uniformly coated on the surface of the lithium titanate particles to improve the electrical conductivity and electrochemical performance of the composite lithium titanate electrode material; the present invention uses the spray drying method to prepare the composite obtained by the spray drying method. The lithium titanate electrode material is porous, that is, has a fixed number of nanochannels, thereby increasing the effective reaction area of the composite lithium titanate electrode material and the reaction channel of lithium ion in and out, so that the composite lithium titanate electrode material has High reversible electrochemical capacity; because the precursor particles obtained by spray drying have the characteristics of small specific surface area, small particle size, uniform particle size distribution and regular particle morphology, the resulting composite titanium is obtained. The lithium acid electrode material has a high tap density, good fluidity and workability.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧Composite lithium titanate electrode material

108‧‧‧Lithium titanate particles

110‧‧‧carbon layer

Claims (10)

A method for preparing a lithium battery electrode material, comprising: providing a lithium source solution and a titanium source particle, wherein the lithium source solution and the titanium source particle have a molar ratio of lithium element to titanium element of 4:5 to 4.5:5. The ratio is uniformly mixed to prepare a sol, the lithium source solution is formed by dissolving a lithium salt or lithium hydroxide in a solvent; providing a carbon source compound, uniformly mixing the sol with the carbon source compound to form a sol a mixed sol consisting of the lithium salt or lithium hydroxide, the titanium source particles, the carbon source compound and the solvent; spray drying the mixed sol to obtain precursor particles; in an inert atmosphere at 400 ° C~ The precursor particles are heated at a temperature of 1000 ° C for 4 to 20 hours to obtain a lithium battery electrode material. The method for producing a lithium battery electrode material according to claim 1, wherein the titanium source particles are titanium dioxide particles, hydrated titanium oxide particles or titanium oxyhydroxide particles. The method for preparing a lithium battery electrode material according to claim 2, wherein the titanium source particles have a particle diameter of 50 nm to 50 μm. The method for producing a lithium battery electrode material according to claim 1, wherein the carbon source compound and the sol are mixed in a ratio of a carbon element to a titanium element in a molar ratio of from 0.1:1 to 2:1. The method for producing a lithium battery electrode material according to claim 1, wherein a surface modifier is further added to the sol before the sol is mixed with the carbon source compound. The method for preparing a lithium battery electrode material according to claim 1, wherein the step of spray drying further comprises: using a peristaltic pump to input the mixed sol at a flow rate of 5 to 40 mL/min under a flow of hot air. In a spray dryer, the hot air has a temperature of 200 ° C to 400 ° C; in the spray dryer, the mixed sol is atomized at a pressure of 0.05 MPa to 0.2 MPa. a droplet of droplets; and causing the mist droplets to co-current with the hot air to form the precursor particles. A method for preparing a lithium battery electrode material, comprising: providing a lithium source solution and a titanium source particle, wherein the lithium source solution and the titanium source particle have a molar ratio of lithium element to titanium element of 4:5 to 4.5:5. The ratio is uniformly mixed to prepare a sol, and the lithium source solution is formed by dissolving a lithium salt or lithium hydroxide in a solvent, the sol from the lithium salt or lithium hydroxide, the titanium source particles and the a solvent composition; spray drying the sol to obtain a plurality of precursor particles; heat treating the precursor particles to prepare a plurality of secondary lithium titanate particles; providing a carbon source compound solution, and obtaining the plurality of secondary titanic acid The lithium particles are uniformly dispersed in the carbon source compound solution to form a mixed solution; and the solvent in the mixed solution is removed, and heat-treated at 400 ° C to 1000 ° C for 4 to 20 hours in an inert gas atmosphere, thereby obtaining a Composite lithium titanate electrode material. The method for preparing a lithium battery electrode material according to claim 7, wherein the heat treatment condition is specifically: heating the precursor particles at 100 ° C to 1000 ° C for 1 hour under an inert gas atmosphere. 20 hours. The method for preparing a lithium battery electrode material according to claim 7, wherein the concentration of the carbon source compound solution is 10% to 40%. The method for preparing a lithium battery electrode material according to claim 7, wherein the obtained plurality of secondary lithium titanate particles are further dispersed in the carbon source compound solution before being dispersed in the carbon source compound solution. Surface modifier.