High lithium content carboxymethyl cellulose lithium and method for preparing the same

Abstract

The present application relates to the technical field of cellulose ether preparation, and particularly relates to high lithium content carboxymethyl cellulose lithium and a preparation method thereof. The preparation method of the high lithium content carboxymethyl cellulose lithium comprises the following steps: after refining cotton is crushed, the cotton is mixed with an isopropyl alcohol aqueous solution to form a slurry; a lithium source is dissolved in the isopropyl alcohol aqueous solution to form an alkali liquor; chlorosuccinic acid is dissolved in the isopropyl alcohol aqueous solution to form an etherification agent solution; urea and the slurry are added to the alkali liquor to perform an alkalization reaction; then the etherification agent solution is added dropwise, and after a preliminary reaction, an etherification reaction is performed; after the reaction is completed, neutralization, centrifugation, stepwise washing with different concentrations of ethanol, drying, crushing, and the like are performed to obtain a carboxymethyl cellulose lithium product. The present application uses chlorosuccinic acid as an etherification agent and urea as an activator, optimizes process parameters, and the prepared carboxymethyl cellulose lithium has high lithium content, high substitution degree and high viscosity, and is suitable for use as a high-performance lithium ion battery negative electrode binder.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cellulose ether preparation, and particularly relates to high-lithium-content carboxymethyl cellulose lithium and a preparation method thereof. BACKGROUND

[0002] The lithium content of traditional carboxymethyl cellulose lithium (CMC-Li) is low, and the reaction of a conventional etherifying agent (chloroacetic acid) is limited. The chloroacetic acid monosodium is only reacted with one molecule of lithium hydroxide, and only one carboxyl group carries lithium when introduced.

[0003] It is difficult to prepare a high-lithium-content product, which leads to insufficient lithium supplementing effect of carboxymethyl cellulose lithium as a negative electrode binder of a lithium battery. The product prepared by an acidification-lithiation two-step method has a high concentration of impurity ions (Na + ), which can form gel particles, reduce the uniformity of slurry, and cause lithium precipitation in a battery. Secondly, the viscosity of carboxymethyl cellulose lithium produced by a conventional method is low, which cannot meet the requirements of high-performance lithium ion batteries on slurry dispersibility and stability.

[0004] Therefore, a carboxymethyl cellulose lithium product with high lithium content, high purity, and high viscosity is crucial for improving battery performance. As a water-based binder for a negative electrode of a lithium ion battery, carboxymethyl cellulose lithium plays three key roles in battery manufacturing: (1) dispersing negative electrode active materials and supplementing lithium; (2) assisting in bonding negative electrode active materials and current collectors; and (3) thickening and preventing negative electrode slurry from settling. High-lithium-content CMC-Li can significantly increase the number of lithium ions that can freely move in a battery, reduce the diffusion distance of lithium ions to the surface of active materials, improve the efficiency of lithium extraction from positive and negative electrode materials, and thus improve the charge and discharge capacity and cycle performance of the battery.

[0005] 1. Acidification-lithiation two-step method (Meishan Jingrui, Chinese patent application for invention CN118684786A)

[0006] ① Limitations of strong acid use

[0007] The process uses 30-80wt% of hydrochloric acid, sulfuric acid or nitric acid in the acidification step, which is highly corrosive and can easily damage equipment. In addition, a large amount of alkaline substances need to be consumed during neutralization, increasing the cost.

[0008] In addition, strong acid treatment can lead to cellulose degradation, and although the product has high viscosity, the number of gel particles is relatively large, which affects the uniformity of the product.

[0009] ② Insufficient control of lithium content and impurities

[0010] The highest lithium content of the product obtained by the method is only 4.4wt%, which is lower than 5.3wt% of the slurry method; the sodium content is 0.05-0.09wt%, which is better than the comparative example, but there is still residual sodium ion, which may affect the electrochemical performance of the lithium battery.

[0011] 2. Water control lithiumation method (Gansu Juntong, Chinese invention patent application CN118359735A)

[0012] The process is complex and energy-intensive, requiring the acidification of CMC-Na to form CMC-H, followed by drying to a moisture content of 10-30%, and then multiple washing and drying steps after the subsequent lithiumation reaction, resulting in a long process and increased energy consumption due to repeated drying steps.

[0013] The acidification solution uses strong acids such as concentrated sulfuric acid and concentrated hydrochloric acid, and the acidification process may produce acidic wastewater containing sodium sulfate, which is difficult to treat.

[0014] Using certain new etherifying agents for etherification reactions may result in a decrease in the degree of substitution of the product compared to using chloroacetic acid for etherification. Additionally, the use of ethanol or acetone as an inhibitor for the lithiumation reaction requires a concentration higher than 2-10% of the swelling critical point, resulting in high organic solvent usage, high recovery costs, and safety hazards. SUMMARY

[0015] In view of the above deficiencies of the prior art, the purpose of the present application is to provide a high-lithium-content carboxymethyl cellulose lithium and a preparation method thereof.

[0016] To achieve the above purpose, the technical solution adopted is:

[0017] One of the purposes of the present application is to provide a preparation method of high-lithium-content carboxymethyl cellulose lithium, comprising the following steps:

[0018] (1) Raw material pretreatment: crush refined cotton to 60-100 mesh to form cellulose powder, mix with 70-98% isopropyl alcohol aqueous solution to form slurry, the amount of isopropyl alcohol involved in the infiltration can ensure that the refined cotton cellulose is uniformly dispersed in the lye; dissolve the lithium source in 70-95% isopropyl alcohol aqueous solution to prepare a lye with a concentration of 3-10%, denoted as solution 1; dissolve chlorosuccinic acid in isopropyl alcohol aqueous solution to prepare a solution with a mass concentration of 50-70%, denoted as solution 2;

[0019] (2) Alkalization reaction: add 3-10% urea based on the mass of cellulose and the slurry of step (1) to solution 1, and stir at 15-40°C for 50-120 minutes under nitrogen protection;

[0020] (3) Etherification reaction: slowly add solution 2 to the system after the alkalization reaction, stir uniformly, then warm up to 70-85°C at a rate of 1-2°C / min, and react for 30-60 minutes;

[0021] (4) Post-processing: the reaction solution is cooled to 30-55℃, neutralized to pH 6.5-8.5 with dilute hydrochloric acid, centrifuged, and then sequentially washed with ethanol (60%-80%) with increasing concentration, vacuum dried at 80-100℃ after centrifugation, crushed and sieved to obtain white powder of carboxymethyl cellulose lithium (CMC-Li) product.

[0022] Preferably, the lithium source is at least one of lithium hydroxide, lithium ethoxide, and lithium carbonate.

[0023] Preferably, the alkalization reaction in step (2) is carried out at 25℃.

[0024] Preferably, in the etherification reaction in step (3), the temperature is raised to 75℃ at a rate of 1-2℃ / min.

[0025] More preferably, the refined cotton in step (1) has an alpha-cellulose content of greater than 95%.

[0026] Preferably, the mass ratio of isopropyl alcohol to cellulose powder in the entire preparation process is 10-20:1.

[0027] The second object of the present application is to provide a high-lithium-content carboxymethyl cellulose lithium, which is prepared by the preparation method of the high-lithium-content carboxymethyl cellulose lithium, has a purity of ≥99.5%, a lithium content of 5.0-5.3wt%, a degree of substitution of 1.09-1.22, and a 1% aqueous solution viscosity of ≥2000 cP.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The etherification agent uses a dicarboxylic acid etherification agent, which uses its dicarboxylic acid groups to increase the degree of substitution and reaction rate. There are three hydroxyl hydrogens on cellulose that can be substituted, which makes chlorosuccinic acid have a higher lithium content at a lower degree of substitution. The use of urea activator increases the reaction degree, making the alkalization and etherification reaction more complete, significantly improving the lithiation efficiency. The segmented temperature control avoids the occurrence of side reactions and ensures the uniformity of the reaction substitution. Process parameter optimization: the use of a mixed solvent system of isopropyl alcohol / water achieves the best balance between solubility and reaction rate of the reactants at this ratio, reducing the solvent consumption ratio. The slurry method can produce products with higher degrees of substitution.

[0030] The production of high lithium content lithium carboxymethyl cellulose means higher lithium ion concentration, which can directly lead to higher ionic conductivity, which is very beneficial to the rapid transmission of ions inside the battery, reduces internal resistance, and improves the rate performance (fast charging and discharging ability). The second point is that good solubility is very important for uniform dispersion in electrolyte, forming a stable electrode slurry and promoting ion transmission inside the electrode. The third point is that high lithium content will lead to relatively stable viscosity of Li-CMC solution, and stable viscosity helps to prepare electrode slurry with better flowability, which is convenient for uniform coating. The fourth point is that Li-CMC contains a large number of lithium ions, which may be beneficial to participate in the formation of a more stable or more beneficial solid electrolyte interface film on the surface of the negative electrode (such as silicon, graphite), while removing the side reactions caused by excess impurity ions (especially Na + )These impurity ions are prone to form gel particles, reduce slurry uniformity, and cause lithium precipitation problems in the battery.

[0031] 1. Process efficiency and energy consumption optimization

[0032] Slurry method does not need step-by-step operation of acidification and then lithiation, directly through alkalization (urea activation) + etherification (chlorosuccinic acid) to increase lithium content in one step, process is shortened by more than 30%, energy consumption is reduced by 20% (compared with multiple drying steps of Gansu Poly Energy Wisdom). Using segmented temperature control, the reaction rate is significantly improved compared to the constant temperature reaction (30-45℃) of Meishan Crystal, and the etherification time is shortened from 3-4 hours to 2.5 hours, and cellulose degradation caused by local overheating is avoided.

[0033] 2. Environmental protection and cost advantage

[0034] Slurry method does not use strong acid acidification, only uses LiOH and urea in alkalization stage, and the acidity of etherification agent chlorosuccinic acid is weaker than that of sulfuric acid / nitric acid, only a small amount of hydrochloric acid is needed to adjust pH during neutralization, and the cost of wastewater treatment is reduced by 50% (compared with strong acid circulation process of Gansu Poly Energy Wisdom). Isopropyl alcohol is used as the reaction medium (concentration 70-98%), the amount of which is 8 times the mass of cellulose, which is 20% less than the amount of ethanol used by Meishan Crystal (1:10-18), and the isopropyl alcohol recovery process is simpler, with a cost reduction of 30%.

[0035] 3. Significant improvement in product performance

[0036] Slurry method destroys the crystalline structure of cellulose through urea activation, with lithium content of 5.0-5.3wt% (compared with 4.4wt% of Meishan Crystal), and degree of substitution of 1.10-1.22, which is more suitable for lithium battery lithium supplementing demand. Segment temperature control reduces degradation, viscosity retention rate > 90%; chloride ion residue < 0.1%, sodium content not detected, purity better than two patents.

[0037] 4. Process stability and applicability

[0038] The slurry method optimizes the parameters such as urea dosage, molar ratio of chlorosuccinic acid by orthogonal experiment, can adjust the lithium content and viscosity according to the demand, has stronger equipment compatibility, does not need strong acid resistant equipment, and has lower equipment requirement and subsequent maintenance cost. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The process flow chart of the application. DETAILED DESCRIPTION

[0040] The application is described below in combination with examples, and the examples are only used for explaining the application, and are not used for limiting the scope of the application.

[0041] Example 1

[0042] The refined cotton is crushed to 60-100 mesh to form cellulose powder, and is mixed with a 70-98% mass fraction isopropanol aqueous solution to form a slurry. 2200g of 90% mass fraction isopropanol, 147g of lithium hydroxide monohydrate are added into a glass reaction kettle and mixed and stirred, after complete dissolution, the temperature is controlled at 20℃, then 150g of the slurry of the refined cotton after soaking is added, after stirring for 30min, 4.5g of urea dissolved in isopropanol solution is added, N2 is passed, stirring is carried out at 25℃ for 90min, 183g of chlorosuccinic acid (60% isopropanol solution) is weighed, that is, 183g of chlorosuccinic acid solid is dissolved in the isopropanol solution to form a 60% concentration chlorosuccinic acid isopropanol solution, which is poured into a constant pressure funnel and slowly dropped into the reaction kettle within 40min, the temperature is controlled at 40℃ for etherification for 60min, the reaction temperature is increased to 75℃ for reaction for 40min, then cooled to 30-55℃, the pH is adjusted to neutral with hydrochloric acid, and after centrifugation after three times of stepwise filtration washing with 60%, 70% and 80% concentration ethanol respectively, drying, crushing are carried out.

[0043] The detection result is: lithium content 5.07wt%, degree of substitution 1.09, viscosity (1% aqueous solution) 2089cP.

[0044] Example 2

[0045] The refined cotton is crushed to 60-100 mesh to form cellulose powder, mixed with 70-98% isopropyl alcohol aqueous solution to form slurry, 2200g of 90% isopropyl alcohol, 147g of lithium hydroxide monohydrate are added into a glass reaction kettle and stirred, after complete dissolution, the solution is recorded as solution 1, the temperature is controlled at 20°C, then 150g of slurry of the refined cotton after complete soaking is added, after stirring for 30min, 6g of urea dissolved in isopropyl alcohol is added, N2 is passed, stirring is carried out at 25°C for 90min, 187.7g of chlorosuccinic acid (60% isopropyl alcohol solution) is weighed and slowly dropped into the reaction kettle through a constant pressure funnel within 40min, the temperature is controlled at 40°C for etherification for 60min, after the reaction temperature is increased to 75°C for 40min, it is cooled to 30-55°C, hydrochloric acid is used to adjust the pH to neutral, after three times of stepwise filtration and washing with 60%, 70% and 80% ethanol respectively and centrifugation, drying and crushing are carried out.

[0046] The detection result is: lithium content 5.18wt%, degree of substitution 1.14, viscosity (1% aqueous solution) 2169cP.

[0047] Example 3

[0048] The refined cotton is crushed to 60-100 mesh to form cellulose powder, mixed with 70-98% isopropyl alcohol aqueous solution to form slurry, 2200g of 90% isopropyl alcohol, 147g of lithium hydroxide monohydrate are added into a glass reaction kettle and stirred, after complete dissolution, the temperature is controlled at 20°C, then 150g of slurry of the refined cotton after complete soaking is added, after stirring for 30min, 6g of urea dissolved in isopropyl alcohol is added, N2 is passed, stirring is carried out at 25°C for 90min, 187.7g of chlorosuccinic acid (60% isopropyl alcohol solution) is weighed and slowly dropped into the reaction kettle through a constant pressure funnel within 40min, the temperature is controlled at 40°C for etherification for 60min, after the reaction temperature is increased to 75°C for 40min, it is cooled to 30-55°C, hydrochloric acid is used to adjust the pH to neutral, after three times of stepwise filtration and washing with 60%, 70% and 80% ethanol respectively and centrifugation, drying and crushing are carried out.

[0049] The detection result is: lithium content 5.18wt%, degree of substitution 1.14, viscosity (1% aqueous solution) 2169cP.

[0050] Example 4

[0051] The refined cotton is crushed to 60-100 mesh to form cellulose powder, mixed with 70-98% isopropyl alcohol aqueous solution to form slurry, 2200g of 90% isopropyl alcohol, 147g of lithium hydroxide monohydrate are added into a glass reaction kettle and stirred, after complete dissolution, the temperature is controlled at 20°C, then 150g of the slurry of the refined cotton after completion of impregnation is added, stirred for 30min, then 4.5g of urea dissolved in isopropyl alcohol is added, N2 is passed, stirred at 25°C for 90min, 183g of chlorosuccinic acid (60% isopropyl alcohol solution) is weighed, poured into a constant pressure funnel and slowly dropped into the reaction kettle within 40min, the temperature is controlled at 45°C for etherification for 65min, the reaction temperature is raised to 77°C for reaction for 45min, then cooled to 30-55°C, neutralized with hydrochloric acid, sequentially washed with 60%, 70% and 80% ethanol by gradient filtration three times, then centrifuged, dried and crushed.

[0052] The detection results are as follows: lithium content 5.12wt%, degree of substitution 1.11, viscosity (1% aqueous solution) 2154cP.

[0053] Comparative Example 1

[0054] The refined cotton is crushed to 60-100 mesh to form cellulose powder, mixed with 70-98% isopropyl alcohol aqueous solution to form slurry, 2200g of 90% isopropyl alcohol, 147g of lithium hydroxide monohydrate are added into a glass reaction kettle and stirred, after complete dissolution, the temperature is controlled at 20°C, then 150g of the slurry of the refined cotton after completion of impregnation is added, stirred for 30min, then 4.5g of urea dissolved in isopropyl alcohol is added, N2 is passed, stirred at 25°C for 90min, 183g of chlorosuccinic acid (60% isopropyl alcohol solution) is weighed, poured into a constant pressure funnel and slowly dropped into the reaction kettle within 40min, the temperature is controlled at 45°C for etherification for 65min, the reaction temperature is raised to 77°C for reaction for 45min, then cooled to 30-55°C, neutralized with hydrochloric acid, sequentially washed with 60%, 70% and 80% ethanol by gradient filtration three times, then centrifuged, dried and crushed.

[0055] The detection results are as follows: lithium content 5.12wt%, degree of substitution 1.11, viscosity (1% aqueous solution) 2154cP.

[0056] Comparative Example 2

[0057] The refined cotton is crushed to 60-100 mesh to form cellulose powder, mixed with 70-98% isopropyl alcohol aqueous solution to form slurry, 2200g of 90% isopropyl alcohol, 147g of lithium hydroxide monohydrate are added into a glass reaction kettle and stirred, after complete dissolution, the temperature is controlled at 20°C, then 150g of the slurry of the refined cotton after completion of impregnation is added, after stirring for 30min, 4.5g of urea dissolved in isopropyl alcohol is added, N2 is passed, stirring is carried out at 25°C for 90min, 125g of chloroacetic acid (60% isopropyl alcohol solution) is weighed and poured into a constant pressure funnel and slowly dropped into the reaction kettle within 40min, the temperature is controlled at 40°C for etherification for 60min, after the reaction temperature is increased to 75°C for 40min, it is cooled to 30-55°C, hydrochloric acid is used to adjust the pH to neutral, after three times of stepwise filtration and washing with 60%, 70% and 80% ethanol respectively and centrifugation, drying and crushing are carried out.

[0058] The detection result is: lithium content 4.14wt%, degree of substitution 1.54, viscosity (1% aqueous solution) 1685cP.

[0059] Comparative Example 3

[0060] The refined cotton is crushed to 60-100 mesh to form cellulose powder, mixed with 70-98% isopropyl alcohol aqueous solution to form slurry, 2200g of 90% isopropyl alcohol, 147g of lithium hydroxide monohydrate are added into a glass reaction kettle and stirred, after complete dissolution, the temperature is controlled at 20°C, then 150g of the slurry of the refined cotton after completion of impregnation is added, after stirring for 30min, 4.5g of urea dissolved in isopropyl alcohol is added, N2 is passed, stirring is carried out at 25°C for 90min, 125g of chloroacetic acid (60% isopropyl alcohol solution) is weighed and poured into a constant pressure funnel and slowly dropped into the reaction kettle within 40min, the temperature is controlled at 40°C for etherification for 60min, after the reaction temperature is increased to 75°C for 40min, it is cooled to 30-55°C, hydrochloric acid is used to adjust the pH to neutral, after three times of stepwise filtration and washing with 60%, 70% and 80% ethanol respectively and centrifugation, drying and crushing are carried out.

[0061] The detection result is: lithium content 3.22wt%, degree of substitution 1.06, viscosity (1% aqueous solution) 1255cP.

[0062] Comparative Example 4

[0063] Refined cotton was crushed to 60-100 mesh to form cellulose powder, mixed with 70-98% isopropyl alcohol aqueous solution to form slurry, 2200g of 90% isopropyl alcohol, 147g of lithium hydroxide monohydrate were added into a glass reaction kettle and stirred until completely dissolved, then the temperature was controlled at 20℃, and then 150g of slurry of the refined cotton was added, stirred for 30min, then 4.5g of urea dissolved in isopropyl alcohol was added, N2 was passed, stirred at 25℃ for 90min, 183g of chlorosuccinic acid (60% isopropyl alcohol solution) was weighed and slowly dropped into the reaction kettle through a constant pressure funnel within 40min, the temperature was controlled at 60℃, and reacted for 100min, then cooled to 30-55℃, adjusted to neutral pH with hydrochloric acid, and then washed with 60%, 70%, and 80% ethanol by gradient filtration three times, centrifuged, and then dried and crushed.

[0064] The detection results are as follows: lithium content 4.75wt%, degree of substitution 0.97, and viscosity (1% aqueous solution) 1895cP.

[0065] 1. Lithium source substitution scheme:

[0066] ① Lithium ethoxide substitution: lithium ethoxide can be used to partially or completely replace lithium hydroxide, and the dosage ratio is m(lithium ethoxide):m(cellulose)=0.7-0.9:1. Lithium ethoxide has better solubility and reactivity, but the cost is higher, and it is suitable for high-end battery products;

[0067] ② Composite lithium source: lithium hydroxide and lithium carbonate are used in combination (mass ratio 3:1-5:1), and lithium carbonate releases lithium ions gradually in the reaction, improving the uniformity of the reaction. This scheme can reduce the severity of the reaction, and is particularly suitable for the preparation of high-substitution-degree products;

[0068] 2. Solvent system substitution scheme

[0069] Isopropyl alcohol-tert-butyl alcohol mixed system: when isopropyl alcohol and tert-butyl alcohol are mixed at a ratio of 75%:25%, the viscosity and degree of substitution of CMC-Li can be significantly improved. This system can promote the uniformity of alkalization and etherification reactions by reducing the polarity of the reaction medium, and reduce side reactions.

[0070] Detection method:

[0071] The inductively coupled plasma emission spectrometry (ICP-OES) was used to test the lithium content, the degree of substitution was calculated by measuring the lithium content of the product, and the Brookfield DV-II+ rotary viscometer was used to measure the viscosity of the prepared 1% aqueous solution.

[0072] Table 1 is an integrated experimental condition table, which clearly presents the experimental parameters and results of the examples and comparative examples under different conditions:

[0073] Table 1. Parameters and performance test data of examples and comparative examples

[0074]

[0075] Table notes:

[0076] 1. Common experimental conditions: all experiments were carried out in a glass reaction kettle, the initial temperature was controlled at 20℃, refined cotton was added, N2 protection was carried out, and after reaction, centrifugation, drying and crushing were carried out.

[0077] 2. Variable comparison:

[0078] Urea dosage: 4.5g for examples 1, 3 and 4, 6g for example 2, and not used for comparative examples 1 and 3.

[0079] Chlorinated reagent: chlorosuccinic acid was used for examples 1-4, and chloroacetic acid was used for comparative examples 2-3, and the samples were different.

[0080] Temperature and time: the etherification temperature and subsequent reaction temperature were adjusted for example 4, the etherification temperature was adjusted for comparative example 4 and there was no subsequent temperature increase reaction, and the temperature control was consistent for the rest of the examples.

[0081] 3. Result analysis: adding urea, using chlorosuccinic acid, and controlling appropriate reaction temperature and time can significantly improve lithium content, degree of substitution and solution viscosity.

[0082] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of high lithium content lithium carboxymethylcellulose, characterized in that, The method comprises the following steps: (1) raw material pretreatment: refining cotton is crushed to 60-100 mesh to form cellulose powder, which is mixed with isopropyl alcohol aqueous solution with a mass fraction of 70-98% to form a slurry; a lithium source is dissolved in isopropyl alcohol aqueous solution with a mass fraction of 70-95% to prepare an alkali liquor with a concentration of 3-10%, which is denoted as solution 1; chlorosuccinic acid is dissolved in isopropyl alcohol aqueous solution to prepare a solution with a mass concentration of 50-70%, which is denoted as solution 2; (2) alkalization reaction: 3-10% of urea based on the mass of cellulose and the slurry in step (1) are added to solution 1, and the mixture is stirred at 25°C for 50-120 minutes under nitrogen protection; (3) etherification reaction: solution 2 is slowly added to the system after the alkalization reaction, and after stirring, preliminary reaction is performed, then the temperature is increased to 75°C at a rate of 1-2°C / min, and reaction is performed for 30-60 minutes; (4) post-treatment: the reaction solution is cooled to 30-55°C, neutralized to pH 6.5-8.5 with dilute hydrochloric acid, centrifuged, and sequentially washed with ethanol with a concentration from low to high, then centrifuged, vacuum dried at 80-100°C, crushed and sieved to obtain white powder of carboxymethyl cellulose lithium product; The lithium source is at least one of lithium hydroxide, lithium ethoxide and lithium carbonate.

2. The process for the preparation of lithium carboxymethylcellulose with high lithium content according to claim 1, characterized in that, The refined cotton in step (1) has an alpha-cellulose content of greater than 95%.

3. A high lithium content lithium carboxymethylcellulose characterized in that, The high-lithium-content carboxymethyl cellulose lithium prepared by the method of any one of claims 1 or 2 has a purity of ≥99.5%, a lithium content of 5.0-5.3 wt%, a degree of substitution of 1.09-1.22, and a 1% aqueous solution viscosity of ≥2000 cP.

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