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CN-116715273-B - Method for producing lithium manganate serving as lithium battery anode material by dry mixing

CN116715273BCN 116715273 BCN116715273 BCN 116715273BCN-116715273-B

Abstract

The invention discloses a method for producing lithium manganate serving as a lithium battery anode material by dry mixing, which comprises the following specific steps of uniformly mixing LiMnO4, manganese dioxide, nano niobium pentoxide, nano aluminum oxide, liOH powder and diboron trioxide at normal temperature, grinding to obtain a mixed material, mixing the powder, stirring and mixing the mixed material in the step I and polyvinyl alcohol, preparing an acidic solution, heating H 2 0, simultaneously adding a mixture of prepared absolute ethyl alcohol and concentrated hydrochloric acid, stirring to obtain the acidic solution, taking out part of the acidic solution, adding the powder into the step II, mixing to obtain a suspension, adding the rest of the acidic solution into the suspension in the step IV, heating and reacting in a sealing ring environment, cooling a reactant after the reaction is finished to obtain emulsion coated crystals, sintering and screening the crystals in the step V, and removing iron from the screened material to obtain a product.

Inventors

  • WU LIZHI
  • YAN WENLONG
  • LIU YUMEI
  • Wang Changzhuang

Assignees

  • 白银大象能源科技有限公司

Dates

Publication Date
20260508
Application Date
20230714

Claims (7)

  1. 1. The method for producing the lithium manganate serving as the positive electrode material of the lithium battery by dry mixing is characterized by comprising the following specific steps of: Uniformly mixing LiMnO 4 , manganese dioxide, nano niobium pentoxide, nano aluminum oxide, liOH powder and diboron trioxide at normal temperature, and grinding to obtain a mixture; step two, stirring and mixing the mixture obtained in the step one and polyvinyl alcohol; Step three, preparing an acidic solution, namely heating H 2 O, adding a mixture of prepared absolute ethyl alcohol and concentrated hydrochloric acid, and stirring to prepare the acidic solution, wherein the pH value of the acidic solution is 3-5; step four, taking out part of the acidic solution, adding the acidic solution into the powder obtained in the step two, and mixing to obtain a suspension; Adding the rest acid solution into the suspension in the fourth step, heating in a sealed environment for reaction, and cooling the reactant after the reaction is finished to obtain emulsion coated crystals; step six, sintering and screening the crystals in the step five; step seven, deironing the sieved material to obtain a product; the reaction conditions in the fifth step are that the reaction temperature is 120-300 ℃, the reaction pressure is 0.5-0.9Mpa, and the reaction time is 1-48h; The temperature of the acid solution in the fourth step is 45-60 ℃ when the acid solution is mixed with the powder, and the temperature of the acid solution in the fifth step is 60-80 ℃ when the acid solution is mixed with the suspension.
  2. 2. The method for producing lithium manganate as a lithium battery cathode material by dry mixing according to claim 1, wherein the first step adopts a planetary ball mill for grinding for 30-60min, and the ground powder is cooled to room temperature and then mixed with polyvinyl alcohol.
  3. 3. The method for producing lithium manganate serving as a lithium battery anode material by dry mixing is characterized in that the weight ratio of absolute ethyl alcohol to concentrated hydrochloric acid in the third step is (1-2) (98-99), and the mass fraction of the concentrated hydrochloric acid is 35-37%.
  4. 4. The method for producing lithium manganate as defined in claim 1, wherein the ratio of the acidic solution added in the fourth step to the acidic solution added in the fifth step is 1:1.
  5. 5. The method for producing lithium manganate as a lithium battery anode material by dry mixing according to claim 1, wherein the sintering and screening method in the step six is characterized by comprising the steps of firstly performing primary sintering, cooling a sintered product, crushing and screening, then taking out an undersize product, performing secondary sintering, cooling the secondarily sintered product, crushing and screening to obtain the undersize product.
  6. 6. The method for producing lithium manganate serving as a lithium battery anode material by dry mixing according to claim 5, wherein the primary sintering is carried out at a temperature rising rate of 1-3 ℃ per minute to 680-850 ℃ and is carried out for 8-24 hours, then the temperature is reduced to 80-250 ℃ according to a temperature reducing rate of 1-3 ℃ per minute, natural cooling is carried out, a double-layer 100-200 mesh screen is adopted for the primary sintering, the secondary sintering is carried out at a temperature rising rate of 1-3 ℃ per minute to 680-900 ℃ and is carried out for 8-24 hours, then the temperature is reduced to 80-250 ℃ according to a temperature reducing rate of 1-3 ℃ per minute, natural cooling is carried out, and a double-layer 100-200 mesh screen is adopted for the secondary sintering.
  7. 7. The method for producing lithium manganate serving as a lithium battery anode material by dry mixing according to claim 1, wherein the molar ratio of LiOH powder to MnO 2 in the first step is (0.7:2) - (1.2:2), and the mass ratio of polyvinyl alcohol in the second step to LiOH powder in the first step is 1 (4-6).

Description

Method for producing lithium manganate serving as lithium battery anode material by dry mixing Technical Field The invention relates to the technical field of lithium batteries, in particular to a method for producing lithium manganate serving as a positive electrode material of a lithium battery by dry mixing. Background At present, the production process of lithium manganate at home and abroad mainly uses a solid-phase mixed high-temperature synthesis method, the adopted manganese source is basically electrolytic MnO 2, and the lithium source comprises Li 2CO3、LiOH·H2 O, liNO 3 and the like. In the traditional solid-phase mixing process, due to factors such as different granularity, different hardness and different specific gravity of raw materials, the phenomenon of insufficient and uniform mixing of the raw materials can be caused when the raw materials are mixed, and the quality of the prepared lithium manganate is further influenced. Disclosure of Invention The invention aims to provide a method for producing lithium manganate serving as a lithium battery anode material by dry mixing, which aims to solve the problem of non-uniform mixing in the prior art. In order to achieve the above purpose, the present invention adopts the following technical scheme: the invention provides a method for producing lithium manganate serving as a lithium battery anode material by dry mixing, which comprises the following specific steps: Uniformly mixing LiMnO4, manganese dioxide, nano niobium pentoxide, nano aluminum oxide, liOH powder and diboron trioxide at normal temperature, and grinding to obtain a mixture; Step two, powder mixing, namely stirring and mixing the mixture obtained in the step one and polyvinyl alcohol; Step three, preparing an acidic solution, namely heating H 2 < 0 >, adding a mixture of prepared absolute ethyl alcohol and concentrated hydrochloric acid, and stirring to prepare the acidic solution; step four, taking out part of the acidic solution, adding the acidic solution into the powder obtained in the step two, and mixing to obtain a suspension; Adding the rest acid solution into the suspension in the fourth step, heating in a sealed environment for reaction, and cooling the reactant after the reaction is finished to obtain emulsion coated crystals; step six, sintering and screening the crystals in the step five; And seventhly, deironing the sieved material to obtain a product. Further, in the first step, a planetary ball mill is adopted for grinding for 30-60min, and the ground powder is cooled to room temperature and then mixed with polyvinyl alcohol. Further, the weight ratio of the absolute ethyl alcohol to the concentrated hydrochloric acid in the third step is (1-2) (98-99), the mass fraction of the concentrated hydrochloric acid is 35-37%, and the pH value of the acid solution in the third step is 3-5. Further, the ratio of the acid solution added in the fourth step to the acid solution added in the fourth step is 1:1. Further, the reaction conditions in the step five are that the reaction temperature is 120-300 ℃, the reaction pressure is 0.5-0.9Mpa, and the reaction time is 1-48h. The sintering and screening method in the step six comprises the steps of firstly carrying out primary sintering, cooling the sintered product, crushing and screening, then taking out the undersize product, carrying out secondary sintering, cooling the secondarily sintered product, crushing and screening to obtain the undersize product. Further, the primary sintering is heated to 680-850 ℃ at the heating rate of 1-3 ℃ per minute, kept for 8-24 hours, then cooled to 80-250 ℃ at the cooling rate of 1-3 ℃ per minute, naturally cooled, the primary sintering material adopts a double-layer 100-200 mesh screen, the secondary sintering material is heated to 680-900 ℃ at the heating rate of 1-3 ℃ per minute, kept for 8-24 hours, then cooled to 80-250 ℃ at the cooling rate of 1-3 ℃ per minute, naturally cooled, and the secondary sintering material adopts the double-layer 100-200 mesh screen. Further, the molar ratio of the LiOH powder to the MnO 2 in the first step is (0.7:2) to (1:2) (1.2:2), Wherein the mass ratio of the polyvinyl alcohol in the second step to the LiOH powder in the first step is 1 (4-6). Further, during the secondary sintering, oxygen is introduced as a combustion improver. Further, when the acidic solution in the fourth step is mixed with the powder, the temperature of the acidic solution is 45-60 ℃, and when the acidic solution in the fifth step is mixed with the suspension, the temperature of the acidic solution is 60-80 ℃. The invention has the beneficial effects that: (1) According to the method for preparing lithium manganate, the lithium source mixture is obtained under the ball mill, the mixture and PVA are coated to form crystal nucleus, the powder is mixed, the influence of the cohesive force of PVA binder and water resistance on the mixing is avoided when the mixture is mixed in the solu