Preparation method and application of SiO2 negative electrode material with high lithium intercalation activity
By performing multiple high-temperature calcination and quenching treatments on crystalline SiO2, combined with ultrasonic dispersion of glucose solution and calcination of inert gas, a highly embedded lithium-active SiO2 negative electrode material was prepared, which solved the problems of low capacity of the negative electrode material of existing lithium-ion batteries and lack of lithium-intercalation activity of silicon dioxide, and achieved the effects of high discharge specific capacity and cycle stability.
Patent Information
- Application Number
- CN202411947957.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-04-04
AI Technical Summary
The negative electrode materials of existing lithium-ion batteries are mainly graphite, with low theoretical capacity, which cannot meet the needs of new energy vehicles. Moreover, silicon dioxide lacks electrochemical lithium embedded activity when used as an anode material, which limits its commercial application.
By calcining and quenching the crystalline SiO2 multiple times at high temperature, a SiO2 negative electrode material with high lithium activity was formed. The method includes calcining SiO2 at high temperature, using a quencher during rapid cooling, followed by ultrasonic dispersion and drying in glucose solution, and finally performing high-temperature calcining in an inert gas to prepare a highly embedded lithium-active SiO2 negative electrode material.
It has achieved high lithium embeddedness activity of SiO2 negative electrode material, improved the discharge specific capacity and cycle stability of lithium-ion batteries, and has a wide range of application prospects in the energy storage field.
Smart Images
Figure CN119750589A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of lithium ion batteries, and in particular to a highly active SiO 2 Preparation method of negative electrode material and its application. Background Art
[0002] With the increasing popularity of new energy vehicles, the current lithium-ion batteries based on graphite negative electrodes can no longer meet the needs of society due to their low theoretical capacity. Therefore, how to develop a new type of ultra-high capacity negative electrode material is a key problem that needs to be urgently solved in the current energy storage field.
[0003] SiO 2 Because of its high theoretical specific capacity (1965mAh g -1 ) and small volume expansion have gradually attracted people's attention. More importantly, SiO 2 When used as negative electrode material, the Li generated in situ during the first week of alloying reaction 2 O and Li 4 SiO 4 , can act as a buffer medium to accommodate the stress caused by volume expansion to a large extent, and protect the generated active nano-silicon. However, due to its high chemical stability, poor intrinsic conductivity and slow lithium ion diffusion coefficient, silicon dioxide is theoretically considered to have no electrochemical lithium insertion activity. Therefore, a SiO2 with high lithium insertion activity was developed. 2 Negative electrode materials are the key to promoting their commercial application. Summary of the invention
[0004] The purpose of the present invention is to provide a high lithium insertion active SiO 2 The preparation method of negative electrode material and its application are simple in steps, rich in raw materials, low in cost, and can realize large-scale production. 2 Negative electrode materials can be used in the field of energy storage.
[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a highly lithium-insertion active SiO 2 The method for preparing the negative electrode material comprises the following steps:
[0006] S1, crystalline SiO 2 Or the crystalline SiO obtained by pretreatment 2 Transfer to a muffle furnace, calcine at high temperature for a period of time and then immediately put into a quenching agent;
[0007] S2, the quenched SiO 2 The materials are collected and step S1 is repeated for multiple calcination and quenching;
[0008] S3, the SiO 2 The material is transferred into a glucose solution of a certain concentration, ultrasonically dispersed for a period of time, and then filtered and dried;
[0009] S4, transferring the material obtained in step S3 to a tube furnace, and calcining at high temperature for a period of time under inert gas to obtain SiO with high lithium insertion activity. 2 Negative electrode material.
[0010] Preferably, in step S1, the calcination temperature is 500-2000° C., and the calcination time is 5-2000 min.
[0011] Preferably, in step S1, the quenching agent is one or more of water, ice water, sodium chloride aqueous solution, liquid nitrogen, liquid ammonia, ethylene glycol, propylene glycol aqueous solution, ethanol aqueous solution, glycerin, and Freon supercooled liquid.
[0012] Preferably, in step S2, the calcination and quenching are repeated 2-10 times.
[0013] Preferably, in step S4, the calcination temperature is 400-1200° C., and the calcination time is 0.5-10 h.
[0014] Preferably, in step S4, the inert gas is one of nitrogen, argon, hydrogen, argon-hydrogen mixed gas, and ammonia.
[0015] Preferably, in step S3, the concentration of the glucose solution is 0.1-10 mol / L.
[0016] Furthermore, in step S1, the pretreatment process is: 2 The material was immersed in concentrated hydrochloric acid solution for a period of time, filtered, washed to remove impurities, and dried to obtain crystalline SiO 2 .
[0017] Preferably, the SiO 2 The material is montmorillonite or sand or a mixture of montmorillonite and sand.
[0018] In order to achieve the above-mentioned object of the invention, the present invention also provides a highly lithium-insertion active SiO prepared by the above-mentioned method. 2 The use of negative electrode materials in the field of energy storage.
[0019] The quenching in the present invention can stabilize the highly defective structure (oxygen vacancies) formed at high temperatures of silicon dioxide in the crystal structure. At high temperatures, atoms in the lattice vibrate around their equilibrium positions, and oxygen atoms as volatile elements diffuse into the air through vibration, leaving oxygen vacancies in the lattice. Rapid quenching avoids the backfilling of dissociated oxygen in the air, so that these high-concentration oxygen vacancies are firmly retained in the bulk lattice. Compared with oxygen vacancies accumulated on the surface prepared by traditional reduction methods, quenching-induced bulk non-stoichiometric defects have higher chemical stability and can essentially optimize the electronic structure and electrochemical activity of the oxide.
[0020] Compared with the prior art solutions, the present invention has the following advantages:
[0021] (1) The raw material of the present invention (crystalline SiO 2 And preparation of crystalline SiO 2 Montmorillonite and sand, etc.) are widely available, green and environmentally friendly, and can be easily and conveniently obtained.
[0022] (2) The present invention has low cost, simple operation method, concise process, and can realize large-scale production.
[0023] (3) The present invention has mild operating conditions and a wide range of applications; the prepared high lithium insertion active SiO 2 The negative electrode material exhibits excellent cycle stability and discharge specific capacity, and has broad application prospects in the field of energy storage. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a SEM image of the comparative material obtained in Comparative Example 1 of the present invention;
[0025] Figure 2 This is a SEM image of the material prepared in Example 1 of the present invention;
[0026] Figure 3 The XRD diagrams of the material prepared in Example 1 of the present invention and the comparative material prepared in Comparative Example 1;
[0027] Figure 4 The first-week charge-discharge curves of the material prepared in Example 1 of the present invention and the comparative material prepared in Comparative Example 1;
[0028] Figure 5 This is a SEM image of the comparative material obtained in Comparative Example 2 of the present invention;
[0029] Figure 6 This is a SEM image of the material prepared in Example 2 of the present invention;
[0030] Figure 7XRD diagrams of the material prepared in Example 2 of the present invention and the comparative material prepared in Comparative Example 2;
[0031] Figure 8 The first-week charge-discharge curves of the material prepared in Example 2 of the present invention and the comparative material prepared in Comparative Example 2;
[0032] Fig. 9 The electrochemical long cycle curves of the material prepared in Example 3 of the present invention and the comparative material prepared in Comparative Example 3 are shown. DETAILED DESCRIPTION
[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0034] Comparative Example 1
[0035] Weigh 10 g of montmorillonite and transfer it to 30 ml of 1 mol / L hydrochloric acid and soak it for 48 hours. Filter it and wash it with deionized water until it is neutral. Transfer the above substance to an oven and dry it for 6-8 hours to obtain the desired material of Comparative Example 1.
[0036] Embodiment 1
[0037] A high lithium insertion active SiO 2 The method for preparing the negative electrode material comprises the following steps:
[0038] S1, the crystalline SiO 2 Transfer to a crucible and place in a muffle furnace. After calcining at 1500°C for 1 hour, clamp the crucible with a crucible tongs and pour the contents of the crucible at high temperature into water to complete quenching.
[0039] S2, SiO in the quenched aqueous solution 2 The powder is collected by filtration and transferred into a crucible, and step S1 is repeated for calcination and quenching 5 times;
[0040] S3, the SiO 2 The material was transferred to 1 mol / L glucose solution, ultrasonically dispersed for 2 h, and then filtered. The collected powder was dried in an oven at 60 °C for 6 h.
[0041] S4, the material obtained in step S3 is transferred to a tube furnace, and calcined at 900°C for 6 hours under nitrogen inert gas to obtain SiO with high lithium insertion activity. 2 Negative electrode material.
[0042] In step S1 of the preparation method of this embodiment, crystalline SiO 2The specific process is as follows: weigh 10g of montmorillonite and transfer it to 30ml of 1mol / L hydrochloric acid to soak for 48h, filter it, wash it with deionized water until it is neutral, transfer the above material to an oven and dry it for 6-8h to obtain crystalline SiO 2 .
[0043] like Figure 1 As shown in the figure, the morphology of montmorillonite after hydrochloric acid treatment is in the state of large particles (tens of microns).
[0044] like Figure 2 As shown, the high lithium insertion activity SiO 2 The material is in a nanoscale particle state. The nanoscale particles ensure a higher electrochemical reaction area and better electrolyte wettability, thereby greatly shortening the path of lithium ion insertion and extraction, greatly improving the kinetic performance of lithium ion electrochemical reactions.
[0045] like Figure 3 As shown, the material prepared in Example 1 exhibits characteristic diffraction peaks that are consistent with SiO 2 The characteristic diffraction peaks of montmorillonite are consistent with those of montmorillonite (JCPDS No.1-649). This shows that after HCl treatment, all the impurities in montmorillonite are removed, and only pure SiO2 is retained. 2 Material.
[0046] like Figure 4 As shown, at a current density of 100 mA / g, the material prepared in Example 1 exhibited a current density of 2774.3 mAh g -1 The discharge capacity of SiO2 is much higher than that of the comparative material obtained in Comparative Example 1 (320 mAh g-1). 2 The electrode material exhibits high electrochemical lithium insertion activity.
[0047] Comparative Example 2
[0048] Weigh 10 g of clean sand from nature and transfer it to 50 ml of 1 mol / L hydrochloric acid and soak it for 72 hours. Filter it and wash it with deionized water until it is neutral. Transfer the above substance to an oven and dry it for 6-8 hours to obtain the required material for comparative example 2.
[0049] Embodiment 2
[0050] A high lithium insertion active SiO 2 The method for preparing the negative electrode material comprises the following steps:
[0051] S1, the crystalline SiO 2Transfer to a crucible and place in a muffle furnace. After calcining at 900°C for 1.5 hours, clamp the crucible with a crucible tongs and pour the contents of the crucible at high temperature into ice water to complete quenching.
[0052] S2, SiO in the quenched aqueous solution 2 The powder is collected by filtration and transferred into a crucible, and step S1 is repeated for calcination and quenching 5 times;
[0053] S3, the SiO 2 The material was transferred to a 2 mol / L glucose solution, ultrasonically dispersed for 2 h, and then filtered. The collected powder was dried in an oven at 60 °C for 6 h.
[0054] S4, the material obtained in step S3 is transferred to a tube furnace and calcined at 900°C for 4 hours under an inert gas of argon to obtain SiO with high lithium insertion activity. 2 Negative electrode material.
[0055] In step S1 of the preparation method of this embodiment, crystalline SiO 2 The specific process is as follows: weigh 10g of natural clean sand and transfer it to 50ml of 1mol / L hydrochloric acid for 72h, filter it, wash it with deionized water until it is neutral, transfer the above material to an oven and dry it for 6-8h to obtain crystalline SiO 2 .
[0056] like Figure 5 As shown, the morphology of the sand after hydrochloric acid treatment presents large particles (tens of microns).
[0057] like Figure 6 As shown, the highly lithium-insertion active SiO 2 The material is in a nanoparticle state, and small nanoparticles ensure higher electrochemical reaction activity. In addition, small nanoparticles have better wettability with the electrolyte, shortening the path of lithium ion insertion and extraction, thereby greatly improving the kinetics of lithium ion electrochemical reactions.
[0058] like Figure 7 As shown, the material obtained in Example 2 exhibits characteristic diffraction peaks that are consistent with SiO 2 The characteristic diffraction peaks of the sand are consistent with those of the sand (JCPDS No.5-490). This shows that after the HCl treatment, all the impurities in the sand are removed, and only the pure phase SiO is retained. 2 Material.
[0059] like Figure 8 As shown, at a current density of 100 mA / g, the material prepared in Example 2 exhibited a current density of 2725.4 mAh g-1 The discharge capacity is much higher than that of the comparative material (505 mAh g -1 This result fully demonstrates that the SiO 2 The electrode material exhibits high electrochemical lithium insertion activity.
[0060] Comparative Example 3
[0061] Weigh 5 g of crystalline SiO 2 As the required materials for comparative example three.
[0062] Embodiment 3
[0063] A high lithium insertion active SiO 2 The method for preparing the negative electrode material comprises the following steps:
[0064] S1, 5g crystalline SiO 2 Transfer to a crucible and place in a muffle furnace. After calcining at 500°C for 1500 min, clamp the crucible with a crucible tongs and pour the contents of the crucible at high temperature into liquid nitrogen to complete quenching.
[0065] S2, SiO in the quenched liquid nitrogen solution 2 The powder is collected by filtration and transferred into a crucible, and step S1 is repeated for calcination and quenching 10 times;
[0066] S3, the SiO 2 The material was transferred to 1 mol / L glucose solution, ultrasonically dispersed for 2 h, and then filtered. The collected powder was dried in an oven at 60 °C for 6 h.
[0067] S4, the material obtained in step S3 is transferred to a tube furnace and calcined at 900°C for 6 hours under Ar gas to obtain SiO with high lithium insertion activity. 2 Negative electrode material.
[0068] like Fig. 9 As shown, at a current density of 100 mA / g, the SiO 2 After 21 cycles, the electrode material still retains 702 mAh g -1 The discharge specific capacity is much higher than that of the material obtained in Comparative Example 3.
Claims
1. A method for preparing a high lithium insertion active SiO2 negative electrode material, characterized in that: The following steps are involved: S1. Transfer the crystalline SiO2 or the crystalline SiO2 obtained through pretreatment into a muffle furnace, and immediately place it into a quenching agent after calcining at high temperature for a period of time; S2, collecting the quenched SiO2 material, and repeating step S1 to perform repeated calcination and quenching; S3, transferring the SiO2 material after the final quenching into a glucose solution of a certain concentration, ultrasonically dispersing it for a period of time, and then filtering and drying it; S4. The material obtained in step S3 is transferred to a tubular furnace and calcined at high temperature for a period of time under an inert gas to obtain a SiO2 negative electrode material with high lithium insertion activity.
2. The method for preparing a high lithium insertion active SiO2 negative electrode material according to claim 1, characterized in that: In step S1, the calcination temperature is 500-2000° C., and the calcination time is 5-2000 min.
3. The method for preparing a SiO2 negative electrode material with high lithium insertion activity according to claim 1 or 2, characterized in that: In step S1, the quenching agent is one or more of water, ice water, sodium chloride aqueous solution, liquid nitrogen, liquid ammonia, ethylene glycol, propylene glycol aqueous solution, ethanol aqueous solution, glycerin, and Freon supercooled liquid.
4. The method for preparing a SiO2 negative electrode material with high lithium insertion activity according to claim 1 or 2, characterized in that: In step S2, the calcination and quenching are repeated 2 to 10 times.
5. A method for preparing a SiO2 negative electrode material with high lithium insertion activity according to claim 1 or 2, characterized in that: In step S4, the calcination temperature is 400-1200° C., and the calcination time is 0.5-10 h.
6. The method for preparing a SiO2 negative electrode material with high lithium insertion activity according to claim 1 or 2, characterized in that: In step S4, the inert gas is one of nitrogen, argon, hydrogen, argon-hydrogen mixed gas, and ammonia.
7. The method for preparing a SiO2 negative electrode material with high lithium insertion activity according to claim 1 or 2, characterized in that: In step S3, the concentration of the glucose solution is 0.1-10 mol / L.
8. The method for preparing a SiO2 negative electrode material with high lithium insertion activity according to claim 1 or 2, characterized in that: In step S1, the pretreatment process is: soaking the substance containing SiO2 in nature in a concentrated hydrochloric acid solution for a period of time, filtering, washing to remove impurities, and drying to obtain crystalline SiO2.
9. The method for preparing a SiO2 negative electrode material with high lithium insertion activity according to claim 8, characterized in that: The SiO2-containing substance is montmorillonite or sand or a mixture of montmorillonite and sand.
10. Use of the high lithium insertion active SiO2 negative electrode material prepared by the method according to any one of claims 1 to 9 in the field of energy storage.