Application of aqueous binder in battery pole piece, battery pole piece and battery

Abstract

The invention belongs to the technical field of battery materials, and discloses application of a water-based binder containing and only containing sodium humate in a battery pole piece. The invention also discloses a battery pole piece taking the sodium humate as the binder and a battery. The aqueous binder in the battery pole piece only contains sodium humate, the components are simple, and the cost is low; water can be used as a solvent and is green and environment-friendly; and the sodium humate is used as a binder of the battery pole piece, so that the structure of the active material can be stabilized to a great extent, and the energy density and cycle life of the battery are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and mainly relates to the application of sodium humate in battery electrode sheets. Background Art

[0002] Most of the positive electrode binders of lithium-ion batteries use oily NMP solvent to dissolve PVDF. PVDF belongs to fluorochemical materials, and the production cost is high. The NMP used to dissolve it is an organic solvent, which is toxic and pollutes the environment. With the replacement of oily PVDF by CMC+SBR for the negative electrode, the use of aqueous binders to replace PVDF for the positive electrode will also become a major trend. The patent document with the publication number CN116387522A discloses an aqueous binder system for sodium-ion batteries, using furoic acid and its derivatives as the first binder and adding CMC as a thickener. The publication number CN109860600A discloses a positive electrode binder for lithium-ion batteries. The binder is an aqueous binder, which is obtained by mixing a modified polyethylene copolymer, deionized water, N,N-dimethylethanolamine, and silica hydrophilically modified with a silane coupling agent. However, the composition of the aqueous binder currently applied in battery electrode sheets is relatively complex. Summary of the Invention

[0003] The first object of the present invention is to provide an application of an aqueous binder in battery electrode sheets.

[0004] The second object of the present invention is to provide a battery electrode sheet.

[0005] The third object of the present invention is to provide a battery.

[0006] To achieve the above objects, the present invention provides the following specific technical solutions.

[0007] Firstly, the present invention provides an application of an aqueous binder containing only sodium humate in battery electrode sheets.

[0008] Secondly, the present invention provides a battery electrode sheet, which is prepared by the following steps: Mix the battery active material, conductive agent, and sodium humate evenly to obtain a dry mixture; Mix the dry mixture with deionized water and stir evenly to obtain a slurry; Coat the slurry on the current collector and dry it to obtain the battery electrode sheet.

[0009] In a further preferred embodiment, the battery active material includes but is not limited to lithium-ion battery positive electrode materials, lithium-ion battery negative electrode materials, sodium-ion battery positive electrode materials, sodium-ion battery negative electrode materials, potassium-ion battery positive electrode materials, and potassium-ion battery negative electrode materials.

[0010] Furthermore, the lithium battery positive electrode material includes but is not limited to lithium iron phosphate, lithium iron manganese phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-rich manganese-based positive electrode materials.

[0011] Furthermore, the lithium battery negative electrode material includes but is not limited to graphite, silicon and silicon-carbon materials.

[0012] Furthermore, the sodium positive electrode material includes but is not limited to sodium vanadium phosphate, sodium vanadium fluorophosphate, and sodium nickel manganate.

[0013] Furthermore, the sodium battery negative electrode material includes but is not limited to hard carbon.

[0014] In a further preferred embodiment, the conductive agent includes but is not limited to carbon black, conductive graphite, acetylene black, SuperP, graphene, Ketjen black, carbon nanotubes, and carbon fibers.

[0015] In a further preferred embodiment, the mass ratio of the battery active material, the conductive agent and the sodium humate in the dry mix is ​​7-9:0.5-2:0.5-2.5.

[0016] In a further preferred embodiment, the mass ratio of the dry mix to deionized water is 1.8-9.5:1.

[0017] In a further preferred embodiment, the current collector includes but is not limited to aluminum foil, carbon-coated aluminum foil, copper foil, and carbon-coated copper foil.

[0018] In a further preferred embodiment, the drying temperature is 25-120°C.

[0019] Based on the same inventive concept, the present invention further provides a battery electrode sheet, which is prepared by the following steps: The battery active material and the conductive agent are mixed uniformly to obtain a dry blend; Mixing sodium humate and deionized water to obtain a binder slurry; mixing the dry mixture with the binder slurry to obtain an electrode slurry; The electrode slurry is evenly coated on the current collector and dried to obtain the electrode plate.

[0020] In a further preferred embodiment, the mass ratio of the battery active material to the conductive agent is 7-9.5:0.5-3.

[0021] In a further preferred embodiment, the mass content of sodium humate in the binder slurry is 10-90%.

[0022] In a further preferred embodiment, the mass ratio of the dry mix to the binder slurry is 8-9.5:0.5-2.

[0023] In addition, the present invention provides a battery, which includes the above-mentioned battery electrode sheet.

[0024] The technical solution provided by the present invention has the following obvious beneficial technical effects: The water-based binder in the battery electrode sheet is sodium humate only, and the composition is simple.

[0025] Sodium humate is relatively easy to extract from coal, and the cost is low, which greatly reduces the manufacturing cost of the battery.

[0026] As the binder of the battery electrode sheet, sodium humate uses water as the solvent, which is green and environmentally friendly and hardly harms the environment.

[0027] As the binder of the battery electrode sheet, sodium humate can greatly stabilize the structure of the active material, improve the energy density and cycle life of the battery, and has very good commercial prospects. Description of the Drawings

[0028] Figure 1 SEM diagram of the battery electrode sheet obtained in Example 1.

[0029] Figure 2 SEM diagram of the battery electrode sheet obtained in Comparative Example 1.

[0030] Figure 3 Cycling performance diagrams of the batteries assembled with the battery electrode sheets obtained in Example 1 and Comparative Example 1 respectively.

[0031] Figure 4 Cycling performance diagrams of the batteries assembled with the battery electrode sheets obtained in Example 2 and Comparative Example 2 respectively.

[0032] Figure 5 Cycling performance diagrams of the batteries assembled with the battery electrode sheets obtained in Example 3 and Comparative Example 3 respectively.

[0033] Figure 6 Cycling performance diagrams of the batteries assembled with the battery electrode sheets obtained in Example 4 and Comparative Example 4 respectively.

[0034] Figure 7 Cycling performance diagrams of the batteries assembled with the battery electrode sheets obtained in Example 5 and Comparative Example 5 respectively.

[0035] Figure 8 Cycling performance diagrams of the batteries assembled with the battery electrode sheets obtained in Example 6 and Comparative Example 6 respectively.

[0036] Fig. 9 Cycling performance diagrams of the batteries assembled with the battery electrode sheets obtained in Example 7 and Comparative Example 7 respectively.

[0037] Fig.10The cycle performance diagrams of batteries assembled with the battery pole pieces obtained in Example 8 and Comparative Example 8 are respectively shown.

[0038] Fig.11 The cycle performance diagrams of batteries assembled with the battery pole pieces obtained in Example 9 and Comparative Example 9 are respectively shown.

[0039] Fig.12 The cycle performance diagrams of batteries assembled with the battery pole pieces obtained in Example 10 and Comparative Example 10 are respectively shown. DETAILED DESCRIPTION

[0040] To achieve the first objective, the present invention provides the use of sodium humate as an aqueous binder in a battery pole piece.

[0041] Commonly used aqueous binders in batteries, such as sodium alginate, CMC, etc., are all swelling-type binders, which require the addition of a large amount of solvent to swell them. Moreover, during the drying process of the electrode pole piece, the swelling-type binder makes the surface of the pole piece very uneven. The present invention uses sodium humate as a binder. Sodium humate is a non-swelling binder and does not require the addition of a large amount of solvent for swelling treatment. Moreover, after sodium humate is mixed with the active material and the conductive agent as an aqueous binder, a slurry is obtained, and the sodium humate in the slurry is very evenly wrapped on the surface of the active material. After the slurry is coated on the current collector, a very dense and flat active layer is obtained after drying. In addition, the sodium ions contained in sodium humate will enter the interior of the electrode material during the charging and discharging process, greatly stabilizing the structure of the positive and negative electrode materials and extending the battery life. Moreover, the binder contains only sodium humate, which simplifies the composition of the existing binder and has extremely high economic benefits.

[0042] To achieve the second objective, the present invention provides a battery electrode sheet, which is prepared by the following steps: The battery active material, the conductive agent and the sodium humate are uniformly mixed to obtain a dry mix; The dry mixture is mixed with deionized water and stirred evenly to obtain a slurry; The slurry is coated on the current collector and dried to obtain the battery electrode.

[0043] Since only sodium humate is used as a binder, the composition of the battery electrode is relatively simple, including only battery active materials, conductive agents and sodium humate.

[0044] Sodium humate is a non-swelling binder, and a slurry can be obtained by adding a very small amount of water. Taking into account the influence of the viscosity of the slurry on the performance of the battery pole piece, the present invention mixes the dry mixture with deionized water at a ratio of 1.8 to 9.5:1.

[0045] It should be noted that the use of sodium humate as an aqueous binder is suitable for almost all battery electrodes, and the active materials of the battery electrodes include but are not limited to lithium battery positive electrode materials, lithium battery negative electrode materials, sodium battery positive electrode materials, sodium battery negative electrode materials, potassium battery positive electrode materials, and potassium battery negative electrode materials.

[0046] Furthermore, the lithium battery positive electrode material includes but is not limited to lithium iron phosphate, lithium iron manganese phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-rich manganese-based positive electrode materials.

[0047] Furthermore, the lithium battery negative electrode material includes but is not limited to graphite, silicon and silicon-carbon materials.

[0048] Furthermore, the sodium positive electrode material includes but is not limited to sodium vanadium phosphate, sodium vanadium fluorophosphate, and sodium nickel manganate.

[0049] Furthermore, the sodium battery negative electrode material includes but is not limited to hard carbon.

[0050] Furthermore, the conductive agent includes but is not limited to carbon black, conductive graphite, acetylene black, Super P, graphene, Ketjen black, carbon nanotubes, and carbon fibers.

[0051] Furthermore, the current collector includes but is not limited to aluminum foil, carbon-coated aluminum foil, copper foil, and carbon-coated copper foil.

[0052] To further optimize the composition of the battery pole piece, in a specific embodiment of the present invention, the mass ratio of the battery active material, the conductive agent, and the sodium humate in the dry mix is ​​7~9:0.5~2:0.5~2.5.

[0053] In a specific embodiment of the present invention, the drying temperature is 25-120°C.

[0054] The mixing method of the materials in the battery pole piece does not affect the performance of the battery pole piece. The battery pole piece can also be prepared by the following steps: The battery active material and the conductive agent are mixed uniformly to obtain a dry blend; Mixing sodium humate and deionized water to obtain a binder slurry; mixing the dry mixture with the binder slurry to obtain an electrode slurry; The electrode slurry is evenly coated on the current collector and dried to obtain the electrode plate.

[0055] In a specific embodiment of the present invention, the mass ratio of the battery active material to the conductive agent is 7-9.5:0.5-3.

[0056] In a specific embodiment of the present invention, the mass content of sodium humate in the binder slurry is 10-90%.

[0057] In a specific embodiment of the present invention, the mass ratio of the dry mix to the binder slurry is 8-9.5:0.5-2.

[0058] To achieve the third objective, the present invention provides a battery, comprising the above-mentioned battery pole piece.

[0059] Since the battery pole pieces are flat and dense, it is beneficial to improve the energy density of the battery system, and the active materials are wrapped in a network of conductive agents and binders, which effectively reduces the side reactions caused by the contact between the active materials and the electrolyte. In addition, the sodium ions contained in the binder sodium humate will produce trace sodium doping in the electrode material during the cycle, which will improve the structural stability of the material to a certain extent.

[0060] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0061] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0062] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0063] Example 1 8 g of lithium cobalt oxide, 1 g of acetylene black conductive agent, and 1 g of sodium humate were weighed and mixed to obtain a dry blend.

[0064] The above dry mixture was added into 2 ml of deionized water and stirred evenly to obtain a slurry.

[0065] The slurry was coated on aluminum foil by doctor blade coating to form a wet electrode sheet with a thickness of 300 μm.

[0066] The wet electrode is dried at 50°C to obtain a battery electrode.

[0067] Figure 1 This is a SEM image of the battery electrode. It can be seen from the image that the electrode is flat and dense, which will greatly improve the energy density of the battery system. In addition, the lithium cobalt oxide particles are wrapped in a network of conductive agents and binders, which will reduce the contact between the active material and the electrolyte and greatly reduce the probability of side reactions, thereby expecting to show excellent electrochemical performance.

[0068] Comparative Example 1 8 g of lithium cobalt oxide, 1 g of acetylene black conductive agent, and 1 g of CMC were weighed and mixed to obtain a dry blend.

[0069] The above dry mixture was added into 2 ml of deionized water and stirred. If the slurry was too viscous, 5 ml of water was added to obtain a slurry.

[0070] The slurry was coated on aluminum foil by doctor blade coating to form a wet electrode sheet with a thickness of 300 μm.

[0071] The wet electrode is dried at 50°C to obtain a battery electrode.

[0072] Figure 2 This is a SEM image of a battery electrode. It can be seen from the image that the electrode is rough and uneven, and a large number of lithium cobalt oxide particles are exposed on the surface of the electrode. This will cause side reactions due to the contact between the active substance and the electrolyte to a large extent, thereby deteriorating the battery performance.

[0073] The battery pole pieces obtained in Example 1 and Comparative Example 1 were assembled into batteries in the following manner: button-type batteries CR2032 were used to assemble half-cells in an argon inert glove box, the negative electrode was lithium metal, and the electrolyte was a commercial electrolyte (1M LiPF 6 The electrical performance of the battery was subsequently tested at a current density of 1C and a cut-off voltage of 3-4.5V. Figure 3 shown.

[0074] It can be seen from the figure that the lithium cobalt oxide matched with sodium humate binder still maintains 168.34 mAh g after 200 cycles. -1 The specific capacity of the CMC binder was 103.63 mAh g after 200 cycles. -1 The specific capacity of the battery is only 62.68%, which shows that the lithium cobalt oxide matched with the sodium humate binder exhibits excellent electrochemical performance.

[0075] Example 2 Weigh 80g of lithium nickel cobalt manganese oxide (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ), 5g Super P conductive agent, and 10g sodium humate are mixed to obtain a dry blend.

[0076] The above dry mixture was added into 10 ml of deionized water and stirred evenly to obtain slurry.

[0077] The slurry was coated on aluminum foil by machine coating to form a wet electrode sheet with a thickness of 500 μm.

[0078] The wet electrode is dried at 80°C to obtain a battery electrode.

[0079] Comparative Example 2 Weigh 80g of lithium nickel cobalt manganese oxide (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ), 5 g Super P conductive agent, and 10 g PVDF were mixed to obtain a dry blend.

[0080] The above dry blend was added into 30 ml of NMP solvent and stirred evenly to obtain slurry.

[0081] The slurry was coated on aluminum foil by machine coating to form a wet electrode sheet with a thickness of 500 μm.

[0082] The wet electrode is dried at 80°C to obtain a battery electrode.

[0083] The battery pole pieces obtained in Example 2 and Comparative Example 2 were assembled into batteries in the following manner: button-type batteries CR2032 were used to assemble half-cells in an argon inert glove box, the negative electrode was lithium metal, and the electrolyte was a commercial electrolyte (1M LiPF 6 The electrical performance of the battery was subsequently tested at a current density of 1C and a cut-off voltage of 2.8-4.4V. The results are shown in Figure 4 As shown. It can be seen that the sodium humate binder matches the LiNi 0.8 Co 0.1 Mn 0.1 O 2 After 100 cycles, it still maintains 170.83 mAh g -1 The specific capacity of the PVDF binder was 136.85 mAh g after 100 cycles. -1 The specific capacity of the battery is only 73.83%, which shows that the lithium cobalt oxide matched with the sodium humate binder exhibits excellent electrochemical performance.

[0084] Example 3 90 g of sodium vanadium phosphate, 20 g of conductive graphite conductive agent, and 15 g of sodium humate were weighed and mixed to obtain a dry blend.

[0085] The above dry blend was added into 25 ml of deionized water and stirred evenly to obtain a slurry.

[0086] The slurry was coated on aluminum foil by machine coating to form a wet electrode sheet with a thickness of 300 μm.

[0087] The wet electrode is dried to obtain a battery electrode.

[0088] Comparative Example 3 90 g of sodium vanadium phosphate, 20 g of conductive graphite conductive agent, and 15 g of PVDF were weighed and mixed to obtain a dry blend.

[0089] The dry blend is added into NMP solvent and stirred evenly to obtain slurry.

[0090] The slurry was coated on aluminum foil by machine coating to form a wet electrode sheet with a thickness of 300 μm.

[0091] The wet electrode is dried to obtain a battery electrode.

[0092] The battery pole pieces obtained in Example 3 and Comparative Example 3 were assembled into batteries in the following manner: button-type batteries CR2032 were used to assemble half-cells in an argon inert glove box, the negative electrode was sodium metal, and the electrolyte was a commercial electrolyte (1M NaPF 6 The electrical performance of the battery was subsequently tested at a current density of 0.5C and a cut-off voltage of 2.8-4.0 V. The results are shown in Figure 5 It can be seen that the sodium vanadium phosphate matched with sodium humate binder still maintains 96.87 mAh g after 100 cycles. -1 The specific capacity of the PVDF binder was 61.69 mAh g after 100 cycles. -1 The specific capacity of the battery was 2.347 W, and the capacity retention rate was only 64.50%. This shows that sodium vanadium phosphate matched with sodium humate binder exhibits excellent electrochemical performance.

[0093] Example 4 80 g of graphite, 5 g of carbon nanotube conductive agent, and 5 g of sodium humate were weighed and mixed to obtain a dry blend.

[0094] The above dry blend was added into 28 ml of deionized water and stirred evenly to obtain a slurry.

[0095] The slurry was coated on the copper foil by machine coating to form a wet electrode with a thickness of 500 μm.

[0096] The wet electrode is dried to obtain a battery electrode.

[0097] Comparative Example 4 80 g of graphite, 5 g of carbon nanotube conductive agent, and 5 g of CMC were weighed and mixed to obtain a dry blend.

[0098] The above dry blend was added into 55 ml of deionized water and stirred evenly to obtain a slurry.

[0099] The slurry was coated on the copper foil by machine coating to form a wet electrode with a thickness of 500 μm.

[0100] The wet electrode is dried to obtain a battery electrode.

[0101] The battery pole pieces obtained in Example 4 and Comparative Example 4 were assembled into batteries in the following manner: button-type batteries CR2032 were used to assemble half-cells in an argon inert glove box, the negative electrode was lithium metal, and the electrolyte was a commercial electrolyte (1M LiPF 6 In a DEC:FEC solvent with a volume ratio of 1:1). -1 The battery cycle performance was tested at a current density and a cut-off voltage of 0.01-2V. The results are as follows Figure 6 It can be seen that the graphite anode matched with sodium humate binder still maintains 278.36 mAh g after 100 cycles. -1 The specific capacity of the PVDF binder was 192.16 mAh g after 100 cycles. -1 The specific capacity of the battery is only 77.30%, which shows that the graphite anode matched with sodium humate binder exhibits excellent electrochemical performance.

[0102] Example 5 80 g of hard carbon, 5 g of acetylene black conductive agent, and 5 g of sodium humate were weighed and mixed to obtain a dry blend.

[0103] The above dry blend was added into 50 ml of deionized water and stirred evenly to obtain a slurry.

[0104] The slurry was coated on the copper foil by machine coating to form a wet electrode with a thickness of 400 μm.

[0105] The wet electrode is dried to obtain a battery electrode.

[0106] Comparative Example 5 80 g of hard carbon, 5 g of acetylene black conductive agent, and 5 g of CMC were weighed and mixed to obtain a dry blend.

[0107] The above dry blend was added into 80 ml of deionized water and stirred evenly to obtain slurry.

[0108] The slurry was coated on the copper foil by machine coating to form a wet electrode with a thickness of 400 μm.

[0109] The wet electrode is dried to obtain a battery electrode.

[0110] The battery pole pieces obtained in Example 5 and Comparative Example 5 were assembled into batteries in the following manner: button-type batteries CR2032 were used to assemble half-cells in an argon inert glove box, the negative electrode was sodium metal, and the electrolyte was a commercial electrolyte (1M NaPF 6The electrical performance of the battery was subsequently tested at a current density of 1C and a cut-off voltage of 0.01-3 V. The results are shown in Figure 7 It can be seen that the hard carbon matched with sodium humate binder still maintains 290.41 mAh g after 100 cycles. -1 The specific capacity of the CMC binder was 226.63 mAh g after 100 cycles. -1 The specific capacity of the battery was 2.347 W, and the capacity retention rate was only 86.09%. This shows that the sodium hard carbon anode matched with the sodium humate binder exhibits excellent electrochemical performance.

[0111] Example 6 70 g of lithium cobalt oxide and 15 g of conductive agent Super P were weighed and mixed evenly to obtain a dry blend.

[0112] Weigh 30 g of sodium humate and dissolve it in 90 mL of water to obtain a binder solution.

[0113] 85 g of the dry blend was added to 10 mL of the binder solution and slurried to obtain electrode slurry.

[0114] The electrode slurry was coated on the aluminum current collector by machine coating to obtain a wet electrode sheet with a thickness of 400 μm.

[0115] The wet electrode is dried to obtain a battery electrode.

[0116] Comparative Example 6 The difference between Comparative Example 6 and Example 6 is that CMC is used instead of sodium humate as the binder.

[0117] The battery electrodes were assembled into batteries in the following manner: a half-cell was assembled in an argon inert glove box using a button cell CR2032, the negative electrode was lithium metal, and the electrolyte was a commercial electrolyte (1M LiPF 6 The electrical performance of the battery was subsequently tested at a current density of 1C and a cut-off voltage of 3-4.5 V. The results are shown in Figure 8 It can be seen that the lithium iron phosphate matched with sodium humate binder still maintains 157.33 mAh g after 300 cycles. -1 The specific capacity of the PVDF binder was 116.47 mAh g after 300 cycles. -1 The specific capacity of the battery is only 74.98%, and the capacity retention rate is only 74.98%. This shows that the lithium iron phosphate matched with sodium humate binder exhibits excellent electrochemical performance.

[0118] Example 7 Weigh 80g of lithium nickel cobalt manganese oxide (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ), and 15 g of conductive agent acetylene black are mixed evenly to obtain a dry blend.

[0119] Weigh 50 g of sodium humate and dissolve it in 50 mL of water to obtain a binder solution.

[0120] 95 g of the dry blend was added to 20 mL of the binder solution and slurried to obtain electrode slurry.

[0121] The electrode slurry was coated on the aluminum current collector by machine coating to obtain a wet electrode sheet with a thickness of 500 μm.

[0122] The wet electrode is dried to obtain a battery electrode.

[0123] Comparative Example 7 The only difference between Comparative Example 7 and Example 7 is that PVDF is used as the binder instead of sodium humate.

[0124] The battery electrodes were assembled into batteries in the following manner: a half-cell was assembled in an argon inert glove box using a button cell CR2032, the negative electrode was lithium metal, and the electrolyte was a commercial electrolyte (1M LiPF 6 The electrical performance of the battery was subsequently tested at a current density of 1C and a cut-off voltage of 2.8-4.4V. Fig. 9 As shown. It can be seen that the sodium humate binder matches the LiNi 0.8 Co 0.1 Mn 0.1 O 2 After 100 cycles, it still maintains 184.44 mAh g -1 The specific capacity of the PVDF binder was 151.7 mAh g after 100 cycles. -1 The specific capacity of the LiNi 0.8 Co 0.1 Mn 0.1 O 2 Exhibits excellent electrochemical performance.

[0125] Example 8 Weigh 90 g of sodium vanadium phosphate and 10 g of conductive agent graphene and mix them evenly to obtain a dry mix.

[0126] Weigh 80 g of sodium humate and dissolve it in 40 mL of water to obtain a binder solution.

[0127] 100 g of the dry mixture was added to 20 mL of the binder solution and slurried to obtain electrode slurry.

[0128] The electrode slurry was coated on the aluminum current collector by machine coating to obtain a wet electrode sheet with a thickness of 300 μm.

[0129] The wet electrode is dried to obtain a battery electrode.

[0130] Comparative Example 8 The only difference between Comparative Example 8 and Example 8 is that PVDF is used as the binder instead of sodium humate.

[0131] The battery electrodes were assembled into batteries in the following manner: a button cell CR2032 was used to assemble a half-cell in an argon inert glove box, the negative electrode was sodium metal, and the electrolyte was a commercial electrolyte (1M NaPF 6 The electrical performance of the battery was subsequently tested at a current density of 0.5C and a cut-off voltage of 2.8-4.0 V. The results are shown in Fig.10 It can be seen that the sodium vanadium phosphate matched with sodium humate binder still maintains 89.42 mAh g after 100 cycles. -1 The specific capacity of the PVDF binder was 50.80 mAh g after 100 cycles. -1 The specific capacity of the battery was 2.347W, and the capacity retention rate was only 82.48%. This shows that sodium vanadium phosphate matched with sodium humate binder exhibits excellent electrochemical performance.

[0132] Example 9 Weigh 80 g of graphite and 15 g of conductive carbon nanotubes and mix them evenly to obtain a dry blend.

[0133] Weigh 50 g of sodium humate and dissolve it in 50 mL of water to obtain a binder solution.

[0134] 80 g of the dry blend was added to 5 mL of the binder solution and slurried to obtain electrode slurry.

[0135] The electrode slurry was coated on the copper current collector by machine coating to obtain a wet electrode sheet with a thickness of 500 μm.

[0136] The wet electrode is dried to obtain a battery electrode.

[0137] Comparative Example 9 The difference between Comparative Example 9 and Example 9 is that CMC is used as a binder instead of sodium humate.

[0138] The battery electrodes were assembled into batteries in the following manner: a half-cell was assembled in an argon inert glove box using a button cell CR2032, the negative electrode was lithium metal, and the electrolyte was a commercial electrolyte (1M LiPF 6 in a DEC:FEC solvent with a volume ratio of 1:1). -1 The electrical performance of the battery was tested at a current density and a cut-off voltage of 0.01-2 V. The results are as follows Fig.11 It can be seen that the graphite anode matched with sodium humate binder still maintains 288.39 mAh g after 200 cycles. -1 The specific capacity of the CMC binder was 206.71 mAh g after 200 cycles. -1 The specific capacity of the battery is only 74.80%, which shows that the graphite anode matched with sodium humate binder exhibits excellent electrochemical performance.

[0139] Example 10 Weigh 80 g of hard carbon and 10 g of conductive agent acetylene black and mix them evenly to obtain a dry blend.

[0140] Weigh 50 g of sodium humate and dissolve it in 50 mL of water to obtain a binder solution.

[0141] 90 g of the dry mixture was added to 10 mL of the binder solution and slurried to obtain electrode slurry.

[0142] The electrode slurry was coated on the copper current collector by machine coating to obtain a wet electrode sheet with a thickness of 500 μm.

[0143] The wet electrode is dried to obtain a battery electrode.

[0144] Comparative Example 10 The difference between Comparative Example 10 and Example 10 is that CMC is used as a binder instead of sodium humate.

[0145] The battery electrodes were assembled into batteries in the following manner: a button cell CR2032 was used to assemble a half-cell in an argon inert glove box, the negative electrode was lithium metal, and the electrolyte was a commercial electrolyte (1M NaPF 6 The electrical performance of the battery was subsequently tested at a current density of 1C and a cut-off voltage of 0.01-3 V. The results are shown in Fig.12 It can be seen that the hard carbon anode matched with sodium humate binder still maintains 288.39 mAh g after 200 cycles. -1The specific capacity of the CMC binder was 206.71 mAh g after 200 cycles. -1 The specific capacity of the battery is only 74.80%, which shows that the graphite anode matched with sodium humate binder exhibits excellent electrochemical performance.

[0146] Based on the above specific examples and comparative examples, it is not difficult to see that the batteries using sodium humate as a binder all exhibited excellent electrochemical cycle performance, which was better than the control samples. This shows that sodium humate is universal as a water-based binder, showing a certain commercial prospect, and is expected to further promote the development of energy storage technology.

[0147] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Application of aqueous binder containing only sodium humate in battery pole pieces.

2. A battery electrode, It is characterized in that The battery electrode is prepared by the following steps: The battery active material, the conductive agent and the sodium humate are uniformly mixed to obtain a dry mix; The dry mixture is mixed with deionized water and stirred evenly to obtain a slurry; The slurry is coated on the current collector and dried to obtain the battery electrode.

3. The battery pole piece according to claim 2, It is characterized in that The mass ratio of the battery active material, the conductive agent and the sodium humate in the dry mix is ​​7-9:0.5-2:0.5-2.

5.

4. The battery pole piece according to claim 2 or 3, It is characterized in that The mass ratio of the dry mix to deionized water is 1.8-9.5:

1.

5. A battery electrode, It is characterized in that The battery electrode is prepared by the following steps: The battery active material and the conductive agent are mixed uniformly to obtain a dry blend; Mixing sodium humate and deionized water to obtain a binder slurry; mixing the dry mixture with the binder slurry to obtain an electrode slurry; The electrode slurry is evenly coated on the current collector and dried to obtain the electrode plate.

6. The battery pole piece according to claim 5, It is characterized in that The mass ratio of the battery active material to the conductive agent is 7-9.5:0.5-3.

7. The battery pole piece according to claim 5, It is characterized in that The mass content of sodium humate in the binder slurry is 10-90%.

8. The battery pole piece according to any one of claims 5 to 7, It is characterized in that The mass ratio of the dry mix to the binder slurry is 8-9.5:0.5-2.

9. A battery, It is characterized in that A battery electrode comprising the battery electrode as described in any one of claims 2 to 8.

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