Lithium formate-based positive electrode lithium supplement material with high capacity and strong environmental stability, preparation method, application and deep-sea energy storage battery

Abstract

This invention proposes a high-capacity and environmentally stable lithium formate-based cathode lithium replenishment material, its preparation method, applications, and deep-sea energy storage batteries. The method uses lithium formate as the main lithium replenishing agent, adding Ketjen black as a conductive agent and stirring until homogeneous to obtain a black mixture. The black mixture is transferred to a nylon ball mill jar, anhydrous ethanol is added, and ball milling is performed to obtain another mixture. The mixture is then dried at high temperature under vacuum to obtain a powder. The powder is dissolved in deionized water, ultrasonically stirred, and magnetically stirred to obtain a black slurry. The slurry is then spray-dried to obtain the high-capacity and environmentally stable cathode lithium replenishment material. Applying this material to lithium-ion batteries can replenish the active lithium lost during battery cycling due to the formation of the solid electrolyte interphase (SEI) film, significantly improving its electrochemical performance. This invention has advantages such as high cost-effectiveness, simple and environmentally friendly preparation process, wide applicability, and excellent electrochemical characteristics.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and particularly to lithium formate-based cathode lithium replenishment materials with high capacity and strong environmental stability, their preparation methods, applications, and deep-sea energy storage batteries. Background Technology

[0002] Lithium-ion batteries (LIBs) are widely used in portable electronic devices and electric vehicles due to their high energy density and long cycle life. However, in existing technologies, the graphite-based anode of lithium-ion batteries consumes a large amount of active lithium during the formation of the solid electrolyte interphase (SEI) film, accompanied by side reactions and decomposition of the electrolyte, resulting in insufficient initial coulombic efficiency (approximately 90%-95%), significantly reducing the battery's energy density and cycle life. High-capacity anode materials (such as silicon, tin, and phosphorus) further exacerbate the lithium loss problem due to their large volume changes during charge and discharge (e.g., silicon 420%, tin 260%, phosphorus 300%). Lithium replenishment technology, as an important strategy, can significantly improve the battery's energy density by providing additional active lithium before cycling.

[0003] Traditional lithium replenishment methods include adding lithium powder, lithium foil, or lithium-rich compounds, but these methods are limited by their high reactivity and stringent environmental requirements. Organic lithium salts, with their low cost, excellent air stability, and high theoretical capacity, have become ideal choices for lithium replenishment materials. Therefore, this invention proposes a cathode lithium replenishment agent based on lithium formate (HLiCO2) with a high theoretical capacity (510 mAh·g). -1 It has good air stability, low decomposition potential, and high application potential. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-capacity and environmentally stable lithium formate-based cathode lithium replenishment material, its preparation method, applications, and deep-sea energy storage batteries. This method uses lithium formate (HLiCO2) and Ketjenblack (KB) as monomers, combined with a simple and scalable ball milling process, followed by spray drying to obtain a high-capacity and environmentally stable cathode lithium replenishment material, namely HLiCO2@KB cathode lithium replenishment material. This electrode material modification method has a simple process and high feasibility, enabling large-scale production of high-capacity and environmentally stable cathode lithium replenishment materials, thereby promoting the practical application of high-performance lithium-ion batteries and possessing significant scientific value and broad practical application prospects.

[0005] The technical solution of this invention is implemented as follows:

[0006] A method for preparing a high-capacity and environmentally stable positive electrode lithium replenishment material, the method comprising using lithium formate and Ketjen black in a mass ratio of 2~4:1~2 as synthetic monomers, ball milling, adding water for dispersion, and finally drying to obtain the positive electrode lithium replenishment material.

[0007] Furthermore, it includes lithium formate and Ketjen black in a mass ratio of 2 to 4:1.

[0008] Furthermore, based on the total weight of the synthetic monomers lithium formate and Ketjen black, the mass ratio of the milling beads to lithium formate and Ketjen black is 1:1 to 1.5; the milling speed is 400 to 600 r / min, and the time is 5 to 8 h; the synthetic monomers are further subjected to grinding treatment before the milling treatment, and the grinding treatment time is 10 to 20 min.

[0009] Furthermore, in the ball milling process, the ratio of small balls to large balls is 3 to 4:1; the particle size of the small balls is 1 mm, and the particle size of the large balls is 3 mm.

[0010] Furthermore, the drying process includes high-temperature spray drying at a temperature of 160-200°C and a gas flow rate of 1-2 L / h. -1 .

[0011] Further, based on the total weight of the synthetic monomers lithium formate and Ketjen black, after ball milling, 20-40 mL of water is added to every 0.7-1 g of the total weight of the synthetic monomers for ultrasonic dispersion, and the ultrasonic dispersion time is 1-2 h; after ultrasonic dispersion, stirring is also performed, and the stirring speed is 500-700 r / min for 10-16 h.

[0012] On the one hand, the present invention also provides a high-capacity and highly environmentally stable positive electrode lithium replenishment material prepared by the above-mentioned method for preparing positive electrode lithium replenishment material.

[0013] The present invention also provides a positive electrode sheet for a deep-sea energy storage battery, the positive electrode sheet comprising the above-mentioned positive electrode lithium replenishment material.

[0014] The present invention also provides a deep-sea energy storage battery, wherein the deep-sea energy storage battery includes the above-mentioned positive electrode plate.

[0015] On the other hand, the present invention also provides an application of a high-capacity and highly environmentally stable cathode lithium replenishment material, such as the above-mentioned cathode lithium replenishment material, including its application as a lithium replenishment additive as a cathode of a lithium-ion battery.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. Since the synthesized HLiCO2@KB cathode lithium replenishment material has a nanoscale core-shell structure, it can maintain both conductivity and reactivity without affecting the crystallinity and high capacity of HLiCO2.

[0018] 2. This invention possesses significant advantages such as low raw material cost, environmentally friendly process, high yield, and large production volume, and exhibits excellent electrochemical performance. This method provides a general optimization strategy aimed at significantly improving the energy density and cycle life of lithium-ion batteries. Given the requirements for superior performance and high reliability in large-scale energy storage systems, this high-capacity and environmentally stable cathode lithium replenishment material shows broad application potential. Attached Figure Description

[0019] Figure 1 SEM image of the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1;

[0020] Figure 2 TEM image of the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1;

[0021] Figure 3 Infrared spectra of the positive electrode lithium replenishment material (denoted as HLiCO2@KB) and lithium formate (HLiCO2) material prepared in Example 1;

[0022] Figure 4 The XRD pattern of the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1;

[0023] Figure 5 The BET spectrum of the positive electrode lithium supplementation material (denoted as HLiCO2@KB) prepared in Example 1;

[0024] Figure 6 EIS diagram of a coin cell lithium-ion half-cell assembled from the positive electrode lithium replenishment material (denoted as HLiCO2@KB) and lithium formate (HLiCO2) material prepared in Example 1;

[0025] Figure 7 The graph shows a comparison of the cycling performance of a coin cell lithium-ion full cell assembled with the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1 and the lithium iron phosphate (LFPO) electrode at a rate of 0.5C.

[0026] Figure 8 A comparison of the rate performance of a coin cell lithium-ion full cell assembled with the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1 and the lithium iron phosphate (LFPO) electrode (denoted as (LFPO@LCKB) electrode) and the lithium iron phosphate (LFPO) electrode.

[0027] Figure 9 Comparison of the cycling performance of coin-type lithium-ion full cells assembled with the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1 (denoted as NCM622@LCKB) and the NCM622 ternary material (NCM622) electrode at a rate of 0.3C.

[0028] Figure 10 Comparison of the cycling performance of coin-type lithium-ion full cells assembled with the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1 and the nickel-cobalt-manganese ternary material (NCM622) electrode (denoted as NCM622@LCKB) and the nickel-cobalt-manganese ternary material (NCM622) electrode at a rate of 1C.

[0029] Figure 11 The graph shows a comparison of the rate performance of a coin cell lithium-ion battery assembled with the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1, which is added to a nickel-cobalt-manganese ternary material (NCM622) electrode and denoted as (NCM622@LCKB) electrode and a nickel-cobalt-manganese ternary material (NCM622) electrode. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0032] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0033] In the agate ball milling beads of this embodiment of the invention, the mass of the small ball with a diameter of 1 mm is 3.125 mg, and the mass of the large ball with a diameter of 3 mm is 84.75 mg.

[0034] Example 1

[0035] A method for preparing a high-capacity and environmentally stable cathode lithium-ion replenishing material is disclosed. This method uses lithium formate (HLiCO2) and Ketjen Black (KB) as monomers, combines a simple and scalable ball milling process, and then proceeds with spray drying to obtain the high-capacity and environmentally stable cathode lithium-ion replenishing material, namely, HLiCO2@KB cathode lithium-ion replenishing material. The specific steps are as follows:

[0036] 1) Add 0.6 g of lithium formate and 0.3 g of Ketjen black to an agate mortar and grind thoroughly for 20 min to obtain a black mixture;

[0037] 2) Add the black mixture obtained in step 1) into a nylon ball milling jar with a capacity of 100 mL containing agate grinding balls, and add 2 mL of anhydrous ethanol; wherein the agate grinding balls have particle sizes of 1 mm and 3 mm, with a quantity ratio of 3:1, 10 large balls and 30 small balls; the ball milling speed is 500 rpm, and the time is 6 h; to obtain the black mixture;

[0038] 3) Transfer the black mixture obtained in step 2) to a 50 mL beaker, add 40 mL of deionized water to the beaker, sonicate for 1 h, place the beaker on a magnetic stirrer, set the speed to 600 rpm, and stir for 12 h to obtain a black slurry;

[0039] 4) Transfer the black slurry obtained in step 3) to a spray dryer and perform high-temperature spray drying at 180°C and a gas flow rate of 1 L / h. -1 After cooling to room temperature, a high-capacity cathode lithium replenishment material with strong environmental stability is obtained.

[0040] The morphology of the prepared positive electrode lithium replenishment material (denoted as HLiCO2@KB) was characterized and analyzed.

[0041] like Figure 1 As shown, HLiCO2@KB is a sphere of amorphous carbon with a rough surface.

[0042] like Figure 2 As shown, HLiCO2@KB has a nanoscale core-shell structure, with an outer shell of amorphous carbon and a core of highly crystalline HLiCO2.

[0043] Depend on Figure 3 It can be concluded that the KB coating on the outside of HLiCO2 did not destroy the crystal structure of HLiCO2 itself.

[0044] Depend on Figure 4 It can be found that the XRD pattern of HLiCO2@KB corresponds to the standard XRD card of HLiCO2, which also shows that the KB coating on the outside of HLiCO2 does not destroy the crystal structure of HLiCO2 itself.

[0045] Depend on Figure 5 The HLiCO2@KB specific surface area can be obtained to be significantly larger.

[0046] Example 2

[0047] Using the high-capacity and environmentally stable cathode lithium-ion supplementation material obtained in Example 1 above, coin-type lithium-ion half-cells were assembled. This material was then added as a lithium iron phosphate (LFPO) electrode and a nickel-cobalt-manganese ternary material (NCM622) electrode to assemble coin-type lithium-ion full-cells, as detailed below:

[0048] (1) The positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in this invention is used as the positive electrode active material of lithium-ion battery, conductive carbon black is used as the conductive agent, and polyvinylidene fluoride is used as the binder; the mass ratio of active material, conductive agent and binder is 6:3:1. After mixing them in proportion, N-methylphthalimide is added to form a slurry, which is then uniformly coated on aluminum foil.

[0049] (2) The positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1 of the present invention is added to lithium iron phosphate (LFPO) at an addition ratio of 10% as the positive electrode active material of lithium-ion battery, conductive carbon black as the conductive agent, and polyvinylidene fluoride as the binder; the mass ratio of active material, conductive agent and binder is 7:2:1. After mixing them in proportion, N-methylphthalimide is added to form a slurry, which is then uniformly coated on aluminum foil.

[0050] (3) The positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared in Example 1 of the present invention is added to the nickel-cobalt-manganese ternary material (NCM622) at an addition ratio of 10% as the positive electrode active material of lithium-ion battery, conductive carbon black as the conductive agent, and polyvinylidene fluoride as the binder; the mass ratio of active material, conductive agent and binder is 8:1:1. After mixing them in proportion, N-methylphthalimide is added to form a slurry, which is then uniformly coated on aluminum foil.

[0051] (4) In this invention, graphite is used as the negative electrode active material of lithium-ion full battery, conductive carbon black is used as the conductive agent, and polyvinylidene fluoride is used as the binder; the mass ratio of active material, conductive agent and binder is 91.6:1.8:6.6. After mixing them in proportion, N-methylphthalimide is added to make a slurry, which is then uniformly coated on copper foil.

[0052] (5) The positive electrode is made by stamping aluminum foil into a circular sheet with a diameter of 10 mm. The mass load of the stamped electrode sheet is 1.6-2.4 mg / cm². -2 .

[0053] (6) The positive electrode is made by stamping copper foil into a circular sheet with a diameter of 10 mm. The mass load of the stamped electrode sheet is 0.8-1.2 mg / cm². -2 .

[0054] (7) CR2016 button batteries were assembled in an argon glove box with polypropylene (PP) as the separator; the lithium-ion electrolyte was 1M LiPF6 dissolved in a solvent mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 3:7.

[0055] 1. Replace the positive electrode lithium replenishment material (denoted as HLiCO2@KB) with lithium formate (HLiCO2), and assemble it with lithium foil in the same way as described above to form a coin cell lithium-ion battery.

[0056] A comparison of two types of coin cell lithium-ion batteries using EIS diagrams, as follows: Figure 6 As shown, the lithium-ion battery assembled with the positive electrode lithium replenishment material (denoted as HLiCO2@KB) has a lower impedance. This demonstrates that the positive electrode lithium replenishment material (denoted as HLiCO2@KB) prepared according to this invention has higher conductivity and electrochemical activity compared to the synthetic monomer lithium formate (HLiCO2).

[0057] 2. Lithium iron phosphate (LFPO) with added positive electrode lithium replenishment material (denoted as HLiCO2@KB) is denoted as LFPO@LCKB. The positive electrode and lithium iron phosphate (LFPO) positive electrode are assembled with graphite negative electrode to form coin cell lithium-ion batteries. The two types of lithium-ion full cells are denoted as Gr||LFPO@LCKB and Gr||LFPO, respectively.

[0058] Comparison of the cycle performance of two coin cell lithium-ion batteries at a rate of 0.5C. Figure 7 As shown: The initial charge capacity of the Gr||LFPO full battery is 143.82 mAh·g. -1 The initial discharge capacity was only 113.36 mAh·g. -1 This is because some active lithium ions are consumed during the formation of the SEI film on the graphite surface and are not replenished.

[0059] The initial charge capacity of the complete Gr||LFPO@LCKB battery is 155.01 mAh·g. -1 Furthermore, because HLiCO2@KB decomposition can provide additional active lithium, the discharge specific capacity is 128.74 mAh·g. -1 It increased by 15.33 mAh·g -1 In 100 cycles, the discharge capacity of the Gr||LFPO@LCKB full cell was significantly higher than that of the Gr||LFPO full cell. This demonstrates that adding a positive electrode lithium replenishment material (denoted as HLiCO2@KB) can significantly improve the capacity of lithium iron phosphate (LFPO) full cells.

[0060] 3. Lithium iron phosphate (LFPO) with added positive electrode lithium replenishment material (denoted as HLiCO2@KB) is denoted as LFPO@LCKB. The positive electrode and lithium iron phosphate (LFPO) positive electrode are assembled with graphite negative electrode to form coin cell lithium-ion batteries. The two types of lithium-ion full cells are denoted as Gr||LFPO@LCKB and Gr||LFPO, respectively.

[0061] Comparison of rate performance of two types of coin cell lithium-ion batteries, for example Figure 8 As shown, when the rate of discharge gradually increases from 0.1C to 0.2C, 0.5C, 1C, 2C, and 5C, the discharge specific capacities of the Gr||LFPO@LCKB full cell are 136.36, 130.61, 124.41, 114.85, 98.55, and 77.8 mAh·g, respectively. -1 The discharge specific capacities of the Gr||LFPO full cells were 127.64, 122.11, 115.22, 104.64, 71.83, and 43.66 mAh·g, respectively. -1 When the current density is 2C, the capacity of the Gr||LFPO@LCKB full cell is much higher than that of the Gr||LFPO full cell. This proves that adding a cathode lithium supplement material (denoted as HLiCO2@KB) can significantly improve the rate performance of lithium iron phosphate (LFPO) full cells.

[0062] 4. The nickel-cobalt-manganese ternary material (NCM622) with added positive electrode lithium supplement material (denoted as HLiCO2@KB) is denoted as NCM622@LCKB. The positive electrode and the nickel-cobalt-manganese ternary material (NCM622) positive electrode are assembled with graphite negative electrode to form coin cell lithium-ion batteries. The two types of lithium-ion full cells are denoted as Gr||NCM622@LCKB and Gr||NCM622, respectively.

[0063] Comparison of the cycle performance of two coin cell lithium-ion batteries at a rate of 0.3C. Figure 9 As shown: The initial charging capacity of the Gr||NCM622 full battery is 204.69 mAh·g. -1 The initial discharge capacity was only 162.59 mAh·g. -1 This is because some active lithium ions are consumed during the formation of the SEI film on the graphite surface and are not replenished.

[0064] The initial charge capacity of the complete Gr||NCM622@LCKB full battery is 238.65 mAh·g. -1 Furthermore, because HLiCO2@KB decomposition can provide additional active lithium, the discharge specific capacity is 176.03 mAh·g. -1 It increased by 13.97 mAh·g -1In 100 cycles, the discharge capacity of the Gr||NCM622@LCKB full cell was significantly higher than that of the Gr||NCM622 full cell. This demonstrates that adding a positive electrode lithium supplement material (denoted as HLiCO2@KB) can significantly improve the capacity of the nickel-cobalt-manganese ternary material (NCM622) full cell.

[0065] 5. The nickel-cobalt-manganese ternary material (NCM622) with added positive electrode lithium supplement material (denoted as HLiCO2@KB) is denoted as NCM622@LCKB. The positive electrode and the nickel-cobalt-manganese ternary material (NCM622) positive electrode are assembled with graphite negative electrode to form coin cell lithium-ion batteries. The two types of lithium-ion full cells are denoted as Gr||NCM622@LCKB and Gr||NCM622, respectively.

[0066] Comparison of the cycle performance of two coin cell lithium-ion batteries at 1C rate. Figure 10 As shown: The initial charging capacity of the Gr||NCM622 full battery is 166.8 mAh·g. -1 The initial discharge capacity was only 124.73 mAh·g. -1 This is because some active lithium ions are consumed during the formation of the SEI film on the graphite surface and are not replenished.

[0067] The initial charge capacity of the complete Gr||NCM622@LCKB full battery is 192.96 mAh·g. -1 Furthermore, because the decomposition of HLiCO2@KB provides additional active lithium, the discharge specific capacity is 145 mAh·g. -1 It increased by 20.27 mAh·g -1 In 300 cycles, the discharge capacity of the Gr||NCM622@LCKB full cell was significantly higher than that of the Gr||NCM622 full cell. This demonstrates that adding a positive electrode lithium supplement material (denoted as HLiCO2@KB) can significantly improve the capacity of the nickel-cobalt-manganese ternary material (NCM622) full cell.

[0068] 6. The nickel-cobalt-manganese ternary material (NCM622) with added positive electrode lithium supplement material (denoted as HLiCO2@KB) is denoted as NCM622@LCKB. The positive electrode and the nickel-cobalt-manganese ternary material (NCM622) positive electrode are assembled with graphite negative electrode to form coin cell lithium-ion batteries. The two types of lithium-ion full cells are denoted as Gr||NCM622@LCKB and Gr||NCM622, respectively.

[0069] Comparison of rate performance of two types of coin cell lithium-ion batteries, for example Figure 11As shown, when the rate of discharge gradually increases from 0.1C to 0.2C, 0.3C, 0.5C, 1C, and 2C, the discharge specific capacities of the Gr||NCM622@LCKB full cell are 179.81, 170.11, 159.73, 149.09, 133.63, and 112.86 mAh·g, respectively. -1 The discharge specific capacities of the Gr||NCM622 full battery were 170.96, 149.79, 127.1, 102.37, 68.92, and 27.12 mAh·g, respectively. -1 When the current density is 0.2C, the capacity of the Gr||NCM622@LCKB full cell is significantly higher than that of the Gr||NCM622 full cell. This demonstrates that adding a cathode lithium supplement material (denoted as HLiCO2@KB) can significantly improve the rate performance of the nickel-cobalt-manganese ternary material (NCM622).

[0070] As described above, the high-capacity and environmentally stable cathode lithium replenishment material prepared in Example 1 of this invention has a nanoscale core-shell structure, with an amorphous carbon outer shell and a highly crystalline HLiCO2 core, resulting in smaller particle size. This addresses the challenge of balancing high capacity and electronic conductivity during material optimization. The modification method for this cathode lithium replenishment material has a simple process and high feasibility, enabling large-scale production of high-capacity and environmentally stable cathode lithium replenishment materials. This promotes the practical application of high-performance lithium-ion batteries, indicating that the high-capacity and environmentally stable cathode lithium replenishment material prepared by this invention has the potential to prepare deep-sea energy storage batteries.

[0071] Example 3

[0072] A method for preparing a high-capacity and environmentally stable cathode lithium-ion replenishing material is disclosed. This method uses lithium formate (HLiCO2) and Ketjen black (KB) as monomers, combines a simple and scalable ball milling process, and then proceeds with spray drying to obtain the high-capacity and environmentally stable cathode lithium-ion replenishing material, namely, HLiCO2@KB cathode lithium-ion replenishing material. The specific steps are as follows:

[0073] 1) Add 0.6 g of lithium formate and 0.2 g of Ketjen black to an agate mortar and grind thoroughly for 20 min to obtain a black mixture;

[0074] 2) Add the black mixture obtained in step 1) into a nylon ball milling jar with a capacity of 100 mL containing agate grinding balls, and add 2 mL of anhydrous ethanol; wherein the agate grinding balls have particle sizes of 1 mm and 3 mm, with a quantity ratio of 3:1, 10 large balls and 30 small balls; the ball milling speed is 500 rpm, and the time is 6 h; to obtain the black mixture;

[0075] 3) Transfer the black mixture obtained in step 2) to a 50 mL beaker, add 40 mL of deionized water to the beaker, sonicate for 1 h, place the beaker on a magnetic stirrer, set the speed to 600 rpm, and stir for 12 h to obtain a black slurry;

[0076] 4) Transfer the black slurry obtained in step 3) to a spray dryer and perform high-temperature spray drying at 180°C and a gas flow rate of 1 L / h. -1 After cooling to room temperature, a high-capacity cathode lithium replenishment material with strong environmental stability is obtained.

[0077] Example 4

[0078] A method for preparing a high-capacity and environmentally stable cathode lithium-ion replenishing material is disclosed. This method uses lithium formate (HLiCO2) and Ketjen black (KB) as monomers, combines a simple and scalable ball milling process, and then proceeds with spray drying to obtain the high-capacity and environmentally stable cathode lithium-ion replenishing material, namely, HLiCO2@KB cathode lithium-ion replenishing material. The specific steps are as follows:

[0079] 1) Add 0.6 g of lithium formate and 0.3 g of Ketjen black to an agate mortar and grind thoroughly for 20 min to obtain a black mixture;

[0080] 2) Add the black mixture obtained in step 1) into a nylon ball milling jar with a capacity of 100 mL containing agate grinding balls, and add 2 mL of anhydrous ethanol; wherein the agate grinding balls have particle sizes of 1 mm and 3 mm, with a quantity ratio of 3:1, 10 large balls and 30 small balls; the ball milling speed is 500 rpm, and the time is 6 h; to obtain the black mixture;

[0081] 3) Transfer the black mixture obtained in step 2) to a 50 mL beaker, add 30 mL of deionized water to the beaker, sonicate for 1 h, place the beaker on a magnetic stirrer, set the speed to 600 rpm, and stir for 12 h to obtain a black slurry;

[0082] 4) Transfer the black slurry obtained in step 3) to a spray dryer and perform high-temperature spray drying at 180°C and a gas flow rate of 1 L / h. -1 After cooling to room temperature, a high-capacity cathode lithium replenishment material with strong environmental stability is obtained.

[0083] Example 5

[0084] A method for preparing a high-capacity and environmentally stable cathode lithium-ion replenishing material is disclosed. This method uses lithium formate (HLiCO2) and Ketjen black (KB) as monomers, combines a simple and scalable ball milling process, and then proceeds with spray drying to obtain the high-capacity and environmentally stable cathode lithium-ion replenishing material, namely, HLiCO2@KB cathode lithium-ion replenishing material. The specific steps are as follows:

[0085] 1) Add 0.6 g of lithium formate and 0.3 g of Ketjen black to an agate mortar and grind thoroughly for 20 min to obtain a black mixture;

[0086] 2) Add the black mixture obtained in step 1) into a nylon ball milling jar with a capacity of 100 mL containing agate grinding balls, and add 2 mL of anhydrous ethanol; wherein the agate grinding balls have particle sizes of 1 mm and 3 mm, with a quantity ratio of 3:1, 10 large balls and 30 small balls; the ball milling speed is 500 rpm, and the time is 6 h; to obtain the black mixture;

[0087] 3) Transfer the black mixture obtained in step 2) to a 50 mL beaker, add 20 mL of deionized water to the beaker, sonicate for 1 h, place the beaker on a magnetic stirrer, set the speed to 600 rpm, and stir for 12 h to obtain a black slurry;

[0088] 4) Transfer the black slurry obtained in step 3) to a spray dryer and perform high-temperature spray drying at 180°C and a gas flow rate of 1 L / h. -1 After cooling to room temperature, a high-capacity cathode lithium replenishment material with strong environmental stability is obtained.

[0089] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing a high-capacity and environmentally stable cathode lithium replenishment material, characterized in that, The preparation method uses lithium formate and Ketjen black in a mass ratio of 2-4:1 as synthetic monomers. The synthetic monomers are ground and then ball-milled. 20-40 mL of water is added to every 0.7-1 g of total synthetic monomer weight, and the mixture is ultrasonically dispersed for 1-2 h. After ultrasonic dispersion, the mixture is stirred at 500-700 r / min for 10-16 h. Finally, it is spray-dried at high temperature to obtain the positive electrode lithium replenishment material. The high-temperature spray drying temperature is 160~200℃, and the gas flow rate is 1~2 L·h. -1 ; Based on the total weight of the synthesized monomers, the ball-to-material mass ratio is 1:1 to 1.5; the ball milling speed is 400 to 600 r / min, and the time is 5 to 8 h; the grinding time is 10 to 20 min. The positive electrode lithium replenishment material has a nanoscale core-shell structure, with an outer shell of amorphous carbon and a core of highly crystalline lithium formate.

2. The method for preparing the positive electrode lithium replenishment material according to claim 1, characterized in that, In the ball milling process, the ratio of small balls to large balls is 3 to 4:1; the particle size of the small balls is 1 mm, and the particle size of the large balls is 3 mm.

3. A high-capacity and highly environmentally stable positive electrode lithium replenishment material prepared by a method according to any one of claims 1-2.

4. A positive electrode sheet for a deep-sea energy storage battery, characterized in that, The positive electrode sheet includes the positive electrode lithium replenishment material as described in claim 3.

5. A deep-sea energy storage battery, characterized in that, The deep-sea energy storage battery includes the positive electrode sheet as described in claim 4.

6. The application of a high-capacity and highly environmentally stable cathode lithium replenishment material, characterized in that, The positive electrode lithium replenishing material as described in any one of claims 1-2 includes its use as a lithium replenishing additive in the positive electrode of a lithium-ion battery.

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