Process for preparing lithium alloy negative electrode for solid-state battery by electrodeposition method

Abstract

The invention discloses a process for preparing a lithium alloy negative electrode for a solid-state battery through an electro-deposition method, and relates to the field of lithium alloy negative electrode piece preparation, the process comprises the following steps: S1, firstly, a lithium piece and a deposition metal piece are respectively fixed in an electro-deposition device, the lithium piece is connected with an anode of an external power supply, and the deposition metal piece is connected with a cathode of the external power supply; according to the process for preparing the lithium alloy negative electrode for the solid-state battery through the electro-deposition method, a deposited metal sheet is immersed into lithium-containing electro-deposition liquid for electro-deposition treatment, and the lithium content in the lithium alloy negative electrode and the surface morphology of the electrode are controlled by controlling the current density, the deposition time and the electro-deposition process; the lithium alloy negative electrode prepared by the method can achieve the purpose of accurately controlling the lithium loading amount in the negative electrode and the bulk phase uniformity of the lithium alloy, an all-solid-state battery assembled by using the alloy prepared by the process as the negative electrode shows excellent electrochemical performance, and the process method is simple, efficient, low in cost and suitable for large-scale continuous preparation.

Description

Technical Field

[0001] The present invention relates to a lithium alloy negative electrode sheet preparation technology, and in particular to a process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method. Background Art

[0002] All-solid-state lithium batteries have become a strong competitor for the next generation of batteries due to their high energy density and high safety. In order to give full play to the high energy density advantage of solid-state batteries, solid-state lithium batteries generally use metallic lithium as the battery negative electrode. Due to the poor chemical stability between the lithium metal negative electrode and the solid electrolyte, all-solid-state batteries with lithium metal as the negative electrode exhibit low initial capacity and short cycle life. Continuous side reactions at the interface between the negative electrode and the electrolyte further lead to a series of problems such as electrolyte decomposition and negative electrode pulverization, ultimately leading to battery failure.

[0003] The current solution in the industry is to use other metals to alloy with lithium to prepare lithium alloys as negative electrodes, alleviate side reactions and improve the electrochemical performance of the negative electrode. The alloying process generally uses methods such as rolling and melting, but the high pressure and high temperature of the equipment will greatly increase the industrial production cost of the battery, and the uniformity of the prepared alloy depends on the mutual diffusion between lithium metal and other metal elements, which will lead to poor uniformity of the two phases of the electrode and the inability to accurately control the lithium content in the alloy. In the alloying process, metallic lithium is generally used as the lithium source. The storage and transportation of highly chemically active metallic lithium will further increase the cost of battery manufacturing.

[0004] Therefore, a process for synthesizing a uniform lithium alloy anode with a specific lithium loading at room temperature and pressure is necessary. Summary of the invention

[0005] The purpose of the present invention is to provide a process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method, so as to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method, comprising the following steps:

[0007] S1. First, a lithium sheet and a deposition metal sheet are fixed inside an electrodeposition device respectively, wherein the lithium sheet is connected to a positive electrode of an external power source, and the deposition metal sheet is connected to a negative electrode of an external power source;

[0008] S2, then injecting the prepared electrodeposition solution into the electrodeposition device, applying power to perform electrodeposition, and obtaining a crude lithium alloy negative electrode sheet after the electrodeposition is completed;

[0009] S3. The crude lithium alloy negative electrode sheet is then cleaned by an electrodeposition device. After cleaning, it is allowed to stand and dry for 1 to 10 hours at 20 to 50° C. to obtain a lithium alloy negative electrode.

[0010] Furthermore, the deposited metal sheet in S1 is a pure metal sheet or an alloy metal sheet, the pure metal sheet is one of a metal indium sheet, a metal tin sheet, a metal copper sheet, a metal nickel sheet, a metal zinc sheet, a metal iron sheet, and a metal aluminum sheet, and the constituent elements of the alloy metal sheet are at least two of the elements lithium, indium, tin, copper, nickel, zinc, iron, aluminum, and carbon.

[0011] Furthermore, the preparation method of the electrodeposition solution described in S2 comprises the following steps: adding a solute into a solvent and mixing them uniformly to obtain the electrodeposition solution;

[0012] The molar concentration of the electrodeposition solution is 0.1 to 5 mol / L;

[0013] The solute is one or more of lithium bis(trifluoromethanesulfonyl imide), lithium bis(fluorosulfonyl imide), lithium hexafluorophosphate, lithium nitrate, lithium tris(pentafluorophenyl) trifluorophosphate, and lithium bis(oxalate)borate;

[0014] The solvent is one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene glycol dimethyl ether, 1,3-dioxolane, methyl butyrate, dimethyl carbonate, and ethyl acetate.

[0015] Furthermore, the electrodeposition process in S2 is constant current electrodeposition, and the discharge system is constant current, and the current density is 0.01-50 mA / cm 2 , the electrodeposition time is 0.1~50h.

[0016] Furthermore, the electrodeposition process in S2 is pulse electrodeposition, and its discharge system is alternating power on and power off, and the power on time is T on The time is 0.1~3600s, and the current is 0.01~1A / cm 2 , power-off time T off 0.1~3600s.

[0017] Furthermore, the electrodeposition process in S2 is reverse pulse electrodeposition, and its discharge system is to cycle according to forward power-on, reverse power-on, and power-off, and the forward power-on time T on The time is 0.1s~3600s, and the current is 0.01~1A / cm 2 , reverse power-on time TR on The duration is 0.05~60s, and the current is 0.01~1A / cm 2 , power-off time T off 0.1~3600s.

[0018] Further, the electrodeposition device comprises an electrodeposition box and a cleaning box, the bottom of the inner wall of the electrodeposition box is fixedly connected with a lithium sheet, the tops of the electrodeposition box and the cleaning box are overlapped with a same splash-proof cover plate, the bottom of the splash-proof cover plate is provided with a transverse driving mechanism, the transverse driving mechanism is provided with an electric telescopic rod, the telescopic end of the electric telescopic rod is fixedly connected with a gantry frame 1, the interior of the gantry frame 1 is rotatably connected with a placement rack, both sides of the top of the placement rack are provided with fixing mechanisms for limiting and fixing the deposited metal sheet, and one side of the gantry frame is also provided with a liquid removal mechanism, the liquid removal mechanism is used to drive the placement rack to rotate and remove liquid;

[0019] A second gantry is fixedly connected between the two sides of the electrodeposition box, a vertical driving mechanism is arranged between the second gantry and the splash-proof cover plate, and the vertical driving mechanism is used to drive the splash-proof cover plate to move up and down;

[0020] The cleaning box is provided with a spray cleaning mechanism, and the spray cleaning mechanism is used to clean the crude lithium alloy negative electrode sheet;

[0021] The electrodeposition box and the cleaning box are both provided with avoidance slots at positions near the tops on opposite sides thereof;

[0022] The spray cleaning mechanism comprises a solution tank fixedly mounted on the cleaning box, a power pump fixedly mounted inside the solution tank, a liquid outlet end of the power pump fixedly connected to a liquid guide tube, the other end of the liquid guide tube passes through the cleaning box and extends to the inside of the cleaning box, and one end of the liquid guide tube extending to the inside of the cleaning box is fixedly connected to a plurality of spray nozzles;

[0023] The dehydration mechanism includes a driving motor fixedly installed on the top of the gantry, the output end of the driving motor is fixedly connected to a driving pulley, the outer surface of the driving pulley is connected to a driven pulley through a transmission belt, the interior of the driven pulley is coaxially fixedly connected to a rotating shaft, and one end of the rotating shaft is fixedly connected to the placement frame, and a protective cover is provided on one side of the gantry, and the protective cover is used to shield and protect the driving pulley, the driven pulley and the transmission belt.

[0024] Furthermore, the lateral driving mechanism includes two fixed plates fixedly installed on the bottom of the splashproof cover plate, a guide rod 1 is fixedly connected between the opposite sides of the two fixed plates, and a servo motor 1 is fixedly connected to one of the fixed plates, a threaded rod 1 is fixedly connected to the output end of the servo motor 1, a driving block is threadedly connected to the outer surface of the threaded rod 1, and the driving block is movably sleeved on the outer surface of the guide rod 1.

[0025] Furthermore, the vertical driving mechanism includes a driving nut, a servo motor and a guide rod. The driving nut is rotatably installed on the top of the gantry. The internal thread of the driving nut is connected to the threaded rod. The servo motor is fixedly installed on the top of the inner wall of the gantry. The output end of the servo motor is fixedly connected to a driving gear. The outer surface of the driving gear is meshed with a driven gear. The driven gear is fixedly sleeved on the outer surface of the driving nut. The guide rod is fixedly installed on the top of the splashproof cover and movably passes through the gantry.

[0026] Furthermore, the fixing mechanism includes an L-shaped frame fixedly installed on the top of the placement rack, the L-shaped frame is provided with a threaded hole, the internal thread of the threaded hole is connected to a threaded rod three, the bottom end of the threaded rod three is rotatably connected to an abutment block, and the top end of the threaded rod three is fixedly connected to a handwheel.

[0027] Compared with the prior art, the present invention provides an electroplating method for preparing a lithium alloy negative electrode for a solid-state battery. The electroplating treatment is performed by immersing a deposited metal sheet in a lithium-containing electroplating solution, and the current density, deposition time, and electroplating process are controlled to control the lithium content in the lithium alloy negative electrode and the surface morphology of the electrode. The lithium alloy negative electrode prepared by the present invention can achieve the purpose of accurately controlling the lithium loading in the negative electrode and the uniformity of the lithium alloy bulk phase. The all-solid-state battery assembled with the alloy prepared by the process as the negative electrode exhibits excellent electrochemical properties. The process method is simple, efficient, and low-cost, and is suitable for large-scale continuous preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0029] Figure 1 A three-dimensional schematic diagram of the overall structure provided by an embodiment of the present invention;

[0030] Figure 2 A three-dimensional schematic diagram of another state of the overall structure provided by an embodiment of the present invention;

[0031] Figure 3 A bottom view of the splash-proof cover plate and the placement rack provided in an embodiment of the present invention;

[0032] Figure 4 A top view of the structures such as the lateral drive mechanism and the placement rack provided in an embodiment of the present invention;

[0033] Figure 5 A top view of the structures such as the dehydration mechanism and the fixing mechanism provided in an embodiment of the present invention;

[0034] Figure 6 A top view of the vertical drive mechanism and splash-proof cover provided in an embodiment of the present invention;

[0035] Figure 7 A schematic diagram of the internal structure of an electrodeposition box and a cleaning box provided in an embodiment of the present invention;

[0036] Figure 8 A schematic diagram of the internal structure of a cleaning box provided in an embodiment of the present invention;

[0037] Fig. 9 A schematic diagram of the structure of an electrodeposition box and a lithium sheet provided in an embodiment of the present invention;

[0038] Fig.10 A schematic diagram of the internal structure of a solution tank provided in an embodiment of the present invention;

[0039] Fig.11 This is a SEM image of the lithium-indium alloy prepared in Example 1 of the present invention;

[0040] Fig.12 This is the XRD pattern of the lithium-indium alloy prepared in Example 1 of the present invention;

[0041] Fig.13 This is a cycle diagram of a lithium-indium alloy solid-state symmetrical battery prepared in Example 1 of the present invention;

[0042] Fig.14 The S-NCM811 / / lithium-indium alloy solid-state full battery cycle performance prepared in Example 1 of the present invention;

[0043] Fig.15 A process flow chart for preparing a lithium alloy negative electrode for a solid-state battery provided in an embodiment of the present invention.

[0044] Description of reference numerals:

[0045] 1. Electrodeposition box; 2. Cleaning box; 3. Lithium sheet; 4. Splash-proof cover;

[0046] 5. lateral drive mechanism; 501. fixed plate; 502. guide rod 1; 503. servo motor 1; 504. threaded rod 1; 505. drive block;

[0047] 6. Electric telescopic rod; 7. Gantry frame 1; 8. Placement rack;

[0048] 9. Fixing mechanism; 901. L-shaped frame; 902. Threaded rod three; 903. Abutment block; 904. Hand wheel;

[0049] 10. Deliquidation mechanism; 1001. Driving motor; 1002. Driving pulley; 1003. Transmission belt; 1004. Driven pulley;

[0050] 11. Gantry 2;

[0051] 12. Vertical drive mechanism; 1201. Drive nut; 1202. Servo motor 2; 1203. Guide rod 2; 1204. Threaded rod 2; 1205. Driving gear; 1206. Driven gear;

[0052] 13. Spray cleaning mechanism; 1301. Solution tank; 1302. Power pump; 1303. Liquid guide tube; 1304. Spray nozzle;

[0053] 14. Avoidance groove. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0055] The specific implementation methods are as follows:

[0056] Cut 0.01-5mm thick lithium metal foil into a circle with a diameter of 10-100mm or a square with a side length of 1-100mm as an anode sheet. Cut the metal sheet to be deposited into a circle with a diameter of 10-100mm or a square with a side length of 1-100mm as a cathode sheet. The metal sheet is one or more of metal indium, metal tin, metal copper, metal nickel, metal zinc, metal iron, metal aluminum and alloys thereof.

[0057] The preparation method of the electrodeposition solution is as follows: a certain mass of solute is weighed as a lithium source for deposition, and the selected solute is one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium nitrate (LiNO3), lithium tris(pentafluorophenyl) trifluorophosphate (LiFAP), and lithium bis(oxalate)borate (LiBOB), preferably LiTFSI, LiFSI, or LiPF6. PF6 is added to a certain volume of solvent; the solvent is one or more of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), ethylene glycol dimethyl ether (DEM), 1,3-dioxolane (DOL), methyl butyrate (MB), dimethyl carbonate (DMC), ethyl acetate (EC), preferably a mixture of DOL and DME, the volume ratio of DME:DOL is 1:0.1-10, and the volume ratio is preferably 1:1. The molar mass of the solute is 0.1-5 mol / L, preferably 1 mol / L.

[0058] Fix the positive and negative poles at the two ends of the electrodeposition tank, connect the lithium plate to the positive pole of the external power supply, connect the deposition metal plate to the negative pole of the external power supply, and inject the configured electrodeposition solution into the electrodeposition tank. Use constant current electrodeposition, pulse electrodeposition, reverse pulse electrodeposition and their combination deposition methods to conduct electrodeposition.

[0059] The prepared lithium alloy negative electrode sheet is taken out and immersed in a solvent for cleaning. The cleaned electrode sheet is dried at a temperature of 20 to 50° C., preferably 30° C., for 1 to 10 hours, preferably 8 hours.

[0060] According to the preparation process of the lithium alloy negative electrode sheet, the specific embodiments are as follows:

[0061] Embodiment 1:

[0062] See also Figure 11-15 , Constant current preparation process of lithium indium alloy negative electrode for solid-state battery

[0063] (1) Cut a 1 mm thick pure lithium sheet into a 50×50 mm square sheet;

[0064] (2) Cutting a pure indium sheet with a thickness of 0.1 mm into a 50×50 mm square sheet;

[0065] (3) Weigh 287.09 g of Li TFSI and dilute the volume to 1 L using a solvent with a volume ratio of DME:DOL = 1:1 to prepare an electrodeposition solution;

[0066] (4) placing the cut lithium sheet and indium sheet into the electrodeposition tank with both ends close to the inner wall of the tank, connecting the lithium sheet to the positive electrode of the external power supply, and connecting the indium sheet to the negative electrode of the external power supply, and injecting the electrodeposition solution;

[0067] (5) Set constant current deposition with a current density of 0.1 A / cm 2 , the lithium-indium alloy sheet was obtained by applying power for 8.3 hours;

[0068] (6) The prepared lithium-indium alloy sheet was subjected to SEM test, and the morphology was as follows: Fig.11 As shown in the figure, it can be seen that the alloy sheet still maintains a flat surface after electrodeposition;

[0069] (7) The prepared lithium-indium alloy sheet was subjected to XRD test. The test results are as follows: Fig.12 As shown;

[0070] (8) The prepared lithium-indium alloy sheet was cut into 10 mm diameter discs, and a symmetrical battery was prepared using LiZrTaCl as a solid electrolyte for testing. The test results are shown in FIG. Fig.13 As shown;

[0071] (9) The positive electrode mixture in the assembled all-solid-state battery is composed of S-NCM811, LiZrTaCl and CNTs, with a mass ratio of 70:30:5, and the positive electrode material surface loading is 7 mg / cm2. 40 mg LPSC l-651 is used as the buffer layer. 70 mg LiZrTaCl is used as the solid electrolyte layer. The assembled all-solid-state battery is charged and discharged under a pressure of 100 MPa. The charge and discharge voltage range is 2.2 to 3.7 V, the current is 1C, and the nominal specific capacity is 200 mA / g. The test results are as follows Fig.14 shown.

[0072] Embodiment 2:

[0073] This example adjusts the ratio of the anode and cathode based on the above example, and the specific process is as follows:

[0074] (1) Cut a 0.5 mm thick pure lithium sheet into a 50×100 mm square sheet;

[0075] (2) Cutting a pure indium sheet with a thickness of 0.3 mm into a 50×100 mm square sheet;

[0076] (3) Weigh 287.09 g of LiTFSI and dilute to 1 L using a solvent with a volume ratio of DME:DOL of 1:1 to prepare an electrodeposition solution;

[0077] (4) placing the cut lithium sheet and indium sheet close to the wall of the electrodeposition tank at both ends of the electrodeposition tank, connecting the lithium sheet to the positive electrode of the external power supply, and the indium sheet to the negative electrode of the external power supply, respectively, and injecting the electrodeposition solution;

[0078] (5) Set constant current deposition with a current density of 0.1A / dm 2 , the lithium-indium alloy sheet was obtained by applying power for 8.3 hours;

[0079] Embodiment 3:

[0080] This example adjusts the ratio of the electrodeposition solution based on the above example, and the specific process is as follows:

[0081] (1) Cut a 0.5 mm thick pure lithium sheet into a 50×100 mm square sheet;

[0082] (2) Cutting a pure indium sheet with a thickness of 0.3 mm into a 50×100 mm square sheet;

[0083] (3) Weigh 151.9 g of Li PF6 and dissolve it in a solvent with a volume ratio of DMC:EC:EMC of 1:1:1 to make a 1 L electrodeposition solution;

[0084] (4) placing the cut lithium sheet and indium sheet close to the wall of the electrodeposition tank at both ends of the electrodeposition tank, connecting the lithium sheet to the positive electrode of the external power supply, and the indium sheet to the negative electrode of the external power supply, respectively, and injecting the electrodeposition solution;

[0085] (5) Set constant current deposition with a current density of 0.1A / dm 2 , the lithium-indium alloy sheet was obtained by applying power for 8.3 hours;

[0086] Embodiment 4:

[0087] This example adjusts the current process based on the above example, and the specific process is as follows:

[0088] (1) Cut a 0.5 mm thick pure lithium sheet into a 50×100 mm square sheet;

[0089] (2) Cutting a pure indium sheet with a thickness of 0.3 mm into a 50×100 mm square sheet;

[0090] (3) Weigh 151.9 g of Li PF6 and dissolve it in a solvent with a volume ratio of DMC:EC:EMC of 1:1:1 to make a 1 L electrodeposition solution;

[0091] (4) placing the cut lithium sheet and indium sheet close to the wall of the electrodeposition tank at both ends of the electrodeposition tank, connecting the lithium sheet to the positive electrode of the external power supply, and the indium sheet to the negative electrode of the external power supply, respectively, and injecting the electrodeposition solution;

[0092] (5) Setting a pulse current process for lithium deposition, the pulse current conduction time is T on The current is 1A / dm 2 , power-off time T off The discharge time is 0.1s, and the lithium-indium alloy sheet is obtained after 10 discharge cycles.

[0093] Embodiment 5:

[0094] This example adjusts the current process based on the above example, and the specific process is as follows:

[0095] (1) Cut a 0.5 mm thick pure lithium sheet into a 50×100 mm square sheet;

[0096] (2) Cutting a pure indium sheet with a thickness of 0.3 mm into a 50×100 mm square sheet;

[0097] (3) Weigh 151.9 g of Li PF6 and dissolve it in a solvent with a volume ratio of DMC:EC:EMC of 1:1:1 to make a 1 L electrodeposition solution;

[0098] (4) placing the cut lithium sheet and indium sheet close to the wall of the electrodeposition tank at both ends of the electrodeposition tank, connecting the lithium sheet to the positive electrode of the external power supply, and the indium sheet to the negative electrode of the external power supply, respectively, and injecting the electrodeposition solution;

[0099] (5) Set the reverse pulse current process for lithium deposition, and the forward power-on time of the pulse current is T on The forward current is 1A / dm 2 , reverse power-on time TR on The reverse current is 2A / dm 2 , power-off time T off The discharge time is 0.1s, and the lithium-indium alloy sheet is obtained after 10 discharge cycles.

[0100] Embodiment 6:

[0101] This example adjusts the electroplating process based on Example 3, and the specific process is as follows:

[0102] (1) Cut a 0.5 mm thick pure lithium sheet into a 50×100 mm square sheet;

[0103] (2) Cutting a pure indium sheet with a thickness of 0.3 mm into a 50×100 mm square sheet;

[0104] (3) Weigh 151.9 g of Li PF6 and dissolve it in a solvent with a volume ratio of DMC:EC:EMC of 1:1:1 to make a 1 L electrodeposition solution;

[0105] (4) placing the cut lithium sheet and indium sheet close to the wall of the electrodeposition tank at both ends of the electrodeposition tank, connecting the lithium sheet to the positive electrode of the external power supply, and the indium sheet to the negative electrode of the external power supply, respectively, and injecting the electrodeposition solution;

[0106] (5) adding a stirring paddle device to the electrodeposition tank to stir the electrodeposition solution until the electrodeposition is completed, and the stirring paddle speed is 100 r / min;

[0107] (6) Set constant current deposition with a current density of 0.1A / dm 2 , the lithium-indium alloy sheet was obtained by applying power for 8.3 hours;

[0108] Embodiment 7:

[0109] This example adjusts the electroplating process based on Example 3, and the specific process is as follows:

[0110] (1) Cut a 0.5 mm thick pure lithium sheet into a 50×100 mm square sheet;

[0111] (2) Cutting a pure indium sheet with a thickness of 0.3 mm into a 50×100 mm square sheet;

[0112] (3) Weigh 151.9 g of Li PF6 and dissolve it in a solvent with a volume ratio of DMC:EC:EMC of 1:1:1 to make a 1 L electrodeposition solution;

[0113] (4) Place the cut lithium sheet and indium sheet close to the wall of the electrodeposition tank and place them at both ends of the temperature-controlled electrodeposition tank, connect the lithium sheet to the positive pole of the external power supply, and connect the indium sheet to the negative pole of the external power supply, inject the electrodeposition solution, and adjust the temperature to 60°C;

[0114] (5) Set constant current deposition with a current density of 0.1A / dm 2 , and the lithium-indium alloy sheet was obtained by applying power for 8.3 hours.

[0115] Embodiment 8:

[0116] See also Figure 1-10 and Fig.15 , a process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method, comprising the following steps:

[0117] S1. First, a lithium sheet and a deposition metal sheet are fixed inside an electrodeposition device respectively, the lithium sheet is connected to the positive electrode of an external power supply, and the deposition metal sheet is connected to the negative electrode of the external power supply;

[0118] S2, then injecting the prepared electrodeposition solution into the electrodeposition device, applying power to perform electrodeposition, and obtaining a crude lithium alloy negative electrode sheet after the electrodeposition is completed;

[0119] S3. The crude lithium alloy negative electrode sheet is then cleaned by an electrodeposition device. After cleaning, it is allowed to stand and dry for 1 to 10 hours at 20 to 50° C. to obtain a lithium alloy negative electrode.

[0120] The S1 deposited metal sheet is a pure metal sheet or an alloy metal sheet. The pure metal sheet is one of metal indium sheet, metal tin sheet, metal copper sheet, metal nickel sheet, metal zinc sheet, metal iron sheet and metal aluminum sheet. The alloy metal sheet is composed of at least two elements of lithium, indium, tin, copper, nickel, zinc, iron, aluminum and carbon.

[0121] S2 A method for preparing an electrodeposition solution, comprising the following steps: adding a solute into a solvent and mixing the mixture uniformly to obtain an electrodeposition solution;

[0122] The molar concentration of the electrodeposition solution is 0.1 to 5 mol / L;

[0123] The solute is one or more of lithium bis(trifluoromethanesulfonyl imide), lithium bis(fluorosulfonyl imide), lithium hexafluorophosphate, lithium nitrate, lithium tris(pentafluorophenyl) trifluorophosphate, and lithium bis(oxalate)borate;

[0124] The solvent is one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene glycol dimethyl ether, 1,3-dioxolane, methyl butyrate, dimethyl carbonate, and ethyl acetate.

[0125] The S2 electrodeposition process is a constant current electrodeposition process, and its discharge system is a constant current, and the current density is 0.01~50mA / cm 2 , the electrodeposition time is 0.1~50h.

[0126] The S2 electrodeposition process is pulse electrodeposition, and its discharge system is alternating power on and power off, and the power on time is T on The time is 0.1~3600s, and the current is 0.01~1A / cm 2 , power-off time T off 0.1~3600s.

[0127] The S2 electrodeposition process is reverse pulse electrodeposition, and its discharge system is to cycle through forward power-on, reverse power-on, and power-off. The forward power-on time is T on The time is 0.1s~3600s, and the current is 0.01~1A / cm 2 , reverse power-on time TR on The duration is 0.05~60s, and the current is 0.01~1A / cm 2 , power-off time T off 0.1~3600s.

[0128] The working environment of the electrodeposition device is a dehydrated and deoxygenated environment. The electrodeposition device includes an electrodeposition box 1 and a cleaning box 2. A lithium sheet 3 is fixedly connected to the bottom of the inner wall of the electrodeposition box 1. A sewage outlet is provided at the bottom of the cleaning box 2. The electrodeposition box 1 is provided with an electrodeposition liquid outlet. The tops of the electrodeposition box 1 and the cleaning box 2 are overlapped with the same splash-proof cover plate 4. A transverse driving mechanism 5 is provided at the bottom of the splash-proof cover plate 4. An electric telescopic rod 6 is provided on the transverse driving mechanism 5. The telescopic end of the electric telescopic rod 6 is fixedly connected to a gantry frame 7. The internal rotation of the gantry frame 7 is connected to a placement rack 8. Both sides of the top of the placement rack 8 are provided with a fixing mechanism 9 for limiting and fixing the deposited metal sheet. A liquid removal mechanism 10 is also provided on one side of the gantry. The liquid removal mechanism 10 is used to drive the placement rack 8 to rotate and remove liquid.

[0129] A gantry 11 is fixedly connected between the two sides of the electrodeposition box 1, and a vertical driving mechanism 12 is provided between the gantry 11 and the splash-proof cover plate 4, and the vertical driving mechanism 12 is used to drive the splash-proof cover plate 4 to move up and down;

[0130] The cleaning box 2 is provided with a spray cleaning mechanism 13, which is used to clean the crude lithium alloy negative electrode sheet;

[0131] The electrodeposition box 1 and the cleaning box 2 are both provided with avoidance grooves 14 at positions near the tops on opposite sides thereof;

[0132] The spray cleaning mechanism 13 includes a solution tank 1301 fixedly mounted on the cleaning box 2, a power pump 1302 fixedly mounted inside the solution tank 1301, a liquid outlet end of the power pump 1302 is fixedly connected with a liquid guide tube 1303, the other end of the liquid guide tube 1303 passes through the cleaning box 2 and extends to the inside of the cleaning box 2, one end of the liquid guide tube 1303 extending to the inside of the cleaning box 2 is fixedly connected with a plurality of spray nozzles 1304, and the top of the solution tank 1301 is fixedly connected with a liquid injection port. Through the arrangement of the spray cleaning mechanism 13, the electrodeposition liquid on the surface of the rough lithium alloy negative electrode sheet obtained by the electrodeposition treatment can be cleaned, thereby improving the cleanliness of the rough lithium alloy negative electrode sheet, and preventing the electrodeposition liquid from dripping onto the ground of the working environment when the rough lithium alloy negative electrode sheet is subsequently transferred, thereby causing environmental pollution and reducing the burden of workers cleaning the ground.

[0133] The dehydration mechanism 10 includes a driving motor 1001 fixedly mounted on the top of the gantry 7, the output end of the driving motor 1001 is fixedly connected to a driving pulley 1002, the outer surface of the driving pulley 1002 is connected to a driven pulley 1004 through a transmission belt 1003, the interior of the driven pulley 1004 is coaxially fixedly connected to a rotating shaft, and one end of the rotating shaft is fixedly connected to the placement rack 8, and a protective cover is provided on one side of the gantry 7, the protective cover is used to shield and protect the driving pulley 1002, the driven pulley 1004 and the transmission belt 1003, through the setting of the dehydration mechanism 10, the placement rack 8 can be driven to rotate, so that after the deposited metal sheet in the placement rack 8 is electroplated, the placement rack 8 is driven to rotate, and the electroplating liquid adsorbed on the surface of the placement rack 8 and the rough lithium alloy negative electrode sheet inside the placement rack 8 is quickly thrown into the electroplating box 1 by the action of centrifugal force, so as to realize the recovery of the electroplating liquid and avoid the waste of the electroplating liquid.

[0134] The transverse driving mechanism 5 includes two fixed plates 501 fixedly installed on the bottom of the splash-proof cover plate 4, a guide rod 502 is fixedly connected between the opposite sides of the two fixed plates 501, and a servo motor 503 is fixedly connected to one of the fixed plates 501, a threaded rod 504 is fixedly connected to the output end of the servo motor 503, a driving block 505 is threadedly connected to the outer surface of the threaded rod 504, and the driving block 505 is movably sleeved on the outer surface of the guide rod 502, and the electric telescopic rod 6 is fixedly installed on the driving block 505. Through the setting of the transverse driving mechanism 5, the placement rack 8 can be driven to transfer from the electrodeposition box 1 and the cleaning box 2, so that after the deposited metal sheet in the placement rack 8 is electroplated, the obtained crude lithium alloy negative electrode sheet can be transferred from the electrodeposition box 1 to the cleaning box 2, so as to clean the negative electrode sheet after electrodeposition and clean the electrodeposition liquid adsorbed on its surface.

[0135] The vertical driving mechanism 12 includes a driving nut 1201, a servo motor 1202 and a guide rod 1203. The driving nut 1201 is rotatably installed on the top of the gantry 11, and the internal thread of the driving nut 1201 is connected to the threaded rod 1204. The servo motor 1202 is fixedly installed on the top of the inner wall of the gantry 11. The output end of the servo motor 1202 is fixedly connected to a driving gear 1205. The outer surface of the driving gear 1205 is meshed with a driven gear 1206. The driven gear 1206 is fixedly sleeved on the outer surface of the driving nut 1201. The guide rod 1203 is fixedly installed on the top of the splashproof cover 4 and movably passes through the gantry. The vertical driving mechanism 12 is used to drive the splashproof cover 4 and the placement frame 8 and other structures to be lifted and lowered.

[0136] The fixing mechanism 9 includes an L-shaped frame 901 fixedly installed on the top of the placement rack 8, and a threaded hole is opened on the L-shaped frame 901. The internal thread of the threaded hole is connected to a threaded rod three 902, and the bottom end of the threaded rod three 902 is rotatably connected to an abutment block 903, and the top end of the threaded rod three 902 is fixedly connected to a handwheel 904. Through the setting of the fixing mechanism 9, the deposited metal sheet placed in the placement rack 8 can be limited and fixed, thereby improving the stability of the deposited metal sheet and preventing the deposited metal sheet from falling off during subsequent electroplating treatment and rotating liquid spinning.

[0137] Working principle: When the electrodeposition device is used to perform electrodeposition treatment on the deposited metal sheet, the vertical drive mechanism 12 is first started, and the output end of the servo motor 1202 in the vertical drive mechanism 12 rotates clockwise, driving the driving gear 1205 to rotate, and driving the driven gear 1206 meshing therewith to rotate, and at the same time, driving the driving nut 1201 to rotate, and under the limiting effect of the guide rod 1203 on the splash-proof cover plate 4 and the threaded rod 1204, the threaded rod 1204 moves upward along the axial direction of the driving nut 1201, and drives the splash-proof cover plate 4 to move upward, and when the splash-proof cover plate 4 moves upward to a suitable position, the vertical drive mechanism 12 is closed;

[0138] At this time, the cleaning box 2 and the electrodeposition box 1 are in an open state, which is convenient for the staff to inject an appropriate amount of prepared electrodeposition liquid into the electrodeposition box 1, and then place the deposited metal sheet to be processed in the placement rack 8, and drive the threaded rod 3 902 to rotate and move in the threaded hole by rotating the hand wheel 904, and drive the abutment block 903 to move until the bottom of the abutment block 903 moves to abut against the top of the deposited metal sheet placed in the placement rack 8, so that the deposited metal sheet is limited and fixed through the cooperation of the placement rack 8 and the fixing mechanism 9;

[0139] Next, the vertical drive mechanism 12 is started again to rotate the output end of its servo motor counterclockwise, indirectly driving the splash-proof cover plate 4 to move downward until the bottom of the splash-proof cover plate 4 overlaps with the top of the cleaning box 2 and the electrodeposition box 1, and then the electric telescopic rod 6 is started to extend its telescopic end, driving the gantry frame 7 to move downward, and driving the placement rack 8 and the deposited metal sheet placed inside the placement rack 8 to move downward until the deposited metal sheet is completely immersed in the electrodeposition liquid in the electrodeposition box 1, and then the lithium sheet 3 in the electrodeposition box 1 is connected to the positive electrode of the external power supply, and the deposited metal sheet is connected to the negative electrode of the external power supply, and power is turned on for electrodeposition treatment, and a crude lithium alloy negative electrode sheet is obtained after the electrodeposition is completed;

[0140] After the electrodeposition treatment is completed, the placement rack 8 and the crude lithium alloy negative electrode sheet inside the placement rack 8 are first moved upward by the extension of the electric telescopic rod 6, so that they are completely out of the electrodeposition liquid, and then the driving motor 1001 is started, and the output end of the driving motor 1001 rotates, driving the active pulley 1002 to rotate, and the kinetic energy is transmitted to the driven pulley 1004 through the transmission belt 1003, and then the placement rack 8 and the crude lithium alloy negative electrode sheet inside the placement rack 8 are driven to rotate through the rotating shaft. During the rotation process, the electrodeposition liquid adsorbed on the surface of the placement rack 8 and the crude lithium alloy negative electrode sheet is quickly thrown into the electrodeposition box 1 by the action of centrifugal force, so as to realize the recovery of the electrodeposition liquid and avoid the waste of the electrodeposition liquid;

[0141] Then, the vertical drive mechanism 12 is started again, and the output end of the servo motor 1202 rotates clockwise, indirectly driving the splash-proof cover plate 4 and the placement rack 8 to move upward, until the bottom of the placement rack 8 moves to above the cleaning box 2 and the electrodeposition box 1, and then the transverse drive mechanism 5 is started, and the output end of the transverse drive mechanism 5 rotates clockwise, driving the threaded rod 1 504 to rotate synchronously, and under the limiting effect of the guide rod 1 502 on the drive block 505, the drive block 505 moves along the axial direction of the threaded rod 1 504 close to the side of the cleaning box 2, and drives the placement rack 8 and the crude lithium alloy negative electrode sheet to move synchronously, until the placement rack 8 moves to just above the cleaning box 2, and then the transverse drive mechanism 5 is closed, and the vertical drive mechanism 12 is started again, and the output end of the servo motor 1202 rotates clockwise. The clockwise rotation indirectly drives the splash-proof cover plate 4 to move down until it abuts against the top of the cleaning box 2. At this time, the placement rack 8 is located inside the cleaning box 2. Then, the deliquescence mechanism 10 and the spray cleaning mechanism 13 are started. The ethylene glycol dimethyl ether in the solution tank 1301 is transported to the spray nozzle 1304 through the liquid guide tube 1303 by the power pump 1302 in the spray cleaning mechanism 13. Finally, the ethylene glycol dimethyl ether is sprayed onto the crude lithium alloy negative electrode sheet in the placement rack 8 by multiple spray nozzles 1304 to clean the crude lithium alloy negative electrode sheet. At the same time, the placement rack 8 and the crude lithium alloy negative electrode sheet are driven to rotate by the deliquescence mechanism 10, which is conducive to the spray cleaning mechanism 13 to evenly rinse and clean the crude lithium alloy negative electrode sheet, thereby effectively improving the cleaning effect and efficiency of the crude lithium alloy negative electrode sheet.

[0142] When the crude lithium alloy negative electrode sheet is cleaned, the deliquoring mechanism 10 is used to drive the crude lithium alloy negative electrode sheet to rotate again, and the centrifugal force is used to shake off the solution adsorbed on the surface of the crude lithium alloy negative electrode sheet, so as to achieve rapid deliquoring, thereby avoiding the solution from dripping and polluting the workshop environment during the process of transporting the crude lithium alloy negative electrode sheet to the storage room (the temperature environment in the storage room is 20-50°C, and it is left to dry for 1-10 hours) after cleaning.

[0143] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method, characterized in that: The steps include: S1. First, a lithium sheet and a deposition metal sheet are fixed inside an electrodeposition device respectively, wherein the lithium sheet is connected to a positive electrode of an external power source, and the deposition metal sheet is connected to a negative electrode of an external power source; S2, then injecting the prepared electrodeposition solution into the electrodeposition device, applying power to perform electrodeposition, and obtaining a crude lithium alloy negative electrode sheet after the electrodeposition is completed; S3. The crude lithium alloy negative electrode sheet is then cleaned by an electrodeposition device. After cleaning, it is allowed to stand and dry for 1 to 10 hours at 20 to 50° C. to obtain a lithium alloy negative electrode.

2. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 1, characterized in that: S1 The deposited metal sheet is a pure metal sheet or an alloy metal sheet, the pure metal sheet is one of a metal indium sheet, a metal tin sheet, a metal copper sheet, a metal nickel sheet, a metal zinc sheet, a metal iron sheet, and a metal aluminum sheet, and the constituent elements of the alloy metal sheet are at least two of the elements lithium, indium, tin, copper, nickel, zinc, iron, aluminum, and carbon.

3. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 1, characterized in that: S2 The method for preparing the electrodeposition solution comprises the following steps: adding a solute into a solvent and mixing the mixture uniformly to obtain the electrodeposition solution; The molar concentration of the electrodeposition solution is 0.1 to 5 mol / L; The solute is one or more of lithium bis(trifluoromethanesulfonyl imide), lithium bis(fluorosulfonyl imide), lithium hexafluorophosphate, lithium nitrate, lithium tris(pentafluorophenyl) trifluorophosphate, and lithium bis(oxalate)borate; The solvent is one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene glycol dimethyl ether, 1,3-dioxolane, methyl butyrate, dimethyl carbonate, and ethyl acetate.

4. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 1, characterized in that: The electrodeposition process described in S2 is constant current electrodeposition, and its discharge system is constant current, and the current density is 0.01~50mA / cm 2 , the electrodeposition time is 0.1~50h.

5. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 1, characterized in that: The electrodeposition process described in S2 is pulse electrodeposition, and its discharge system is alternating power on and power off, and the power on time is T on The time is 0.1~3600s, and the current is 0.01~1A / cm 2 , power-off time T off 0.1~3600s.

6. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 1, characterized in that: The electrodeposition process described in S2 is reverse pulse electrodeposition, and its discharge system is to cycle according to forward power-on, reverse power-on, and power-off. The forward power-on time T on The time is 0.1s~3600s, and the current is 0.01~1A / cm 2 , reverse power-on time TR on The duration is 0.05~60s, and the current is 0.01~1A / cm 2 , power-off time T off 0.1~3600s.

7. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 1, characterized in that: The electrodeposition device comprises an electrodeposition box (1) and a cleaning box (2), wherein a lithium sheet (3) is fixedly connected to the bottom of the inner wall of the electrodeposition box (1), and the tops of the electrodeposition box (1) and the cleaning box (2) are overlapped with a same splash-proof cover plate (4), and a transverse driving mechanism (5) is arranged at the bottom of the splash-proof cover plate (4), and an electric telescopic rod (6) is arranged on the transverse driving mechanism (5), and the telescopic end of the electric telescopic rod (6) is fixedly connected to a gantry frame (7), and the interior of the gantry frame (7) is rotatably connected to a placement rack (8), and both sides of the top of the placement rack (8) are provided with fixing mechanisms (9) for limiting and fixing the deposited metal sheet, and a dehydration mechanism (10) is also arranged on one side of the gantry, and the dehydration mechanism (10) is used to drive the placement rack (8) to rotate and dehydrate; A same gantry frame 2 (11) is fixedly connected between the two sides of the electrodeposition box (1), and a vertical driving mechanism (12) is provided between the gantry frame 2 (11) and the splash-proof cover plate (4), and the vertical driving mechanism (12) is used to drive the splash-proof cover plate (4) to move up and down; The cleaning box (2) is provided with a spray cleaning mechanism (13), and the spray cleaning mechanism (13) is used to clean the crude lithium alloy negative electrode sheet; The electrodeposition box (1) and the cleaning box (2) are both provided with avoidance grooves (14) at positions near the top ends on opposite sides thereof; The spray cleaning mechanism (13) comprises a solution tank (1301) fixedly mounted on the cleaning tank (2); a power pump (1302) is fixedly mounted inside the solution tank (1301); a liquid outlet end of the power pump (1302) is fixedly connected to a liquid guide tube (1303); the other end of the liquid guide tube (1303) passes through the cleaning tank (2) and extends to the inside of the cleaning tank (2); one end of the liquid guide tube (1303) extending to the inside of the cleaning tank (2) is fixedly connected to a plurality of spray nozzles (1304); The dehydration mechanism (10) comprises a driving motor (1001) fixedly mounted on the top of a gantry frame (7); the output end of the driving motor (1001) is fixedly connected to a driving pulley (1002); the outer surface of the driving pulley (1002) is connected to a driven pulley (1004) via a transmission belt (1003); the interior of the driven pulley (1004) is coaxially fixedly connected to a rotating shaft, and one end of the rotating shaft is fixedly connected to a placement frame (8).

8. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 7, characterized in that: The transverse driving mechanism (5) comprises two fixing plates (501) fixedly mounted on the bottom of the splash-proof cover plate (4), a guide rod (502) being fixedly connected between opposite sides of the two fixing plates (501), and a servo motor (503) being fixedly connected to one of the fixing plates (501), a threaded rod (504) being fixedly connected to the output end of the servo motor (503), a driving block (505) being threadedly connected to the outer surface of the threaded rod (504), and the driving block (505) being movably sleeved on the outer surface of the guide rod (502).

9. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 8, characterized in that: The vertical drive mechanism (12) comprises a driving nut (1201), a second servo motor (1202) and a second guide rod (1203); the driving nut (1201) is rotatably mounted on the top of the second gantry (11), and the internal thread of the driving nut (1201) is connected to the second threaded rod (1204); the second servo motor (1202) is fixedly mounted on the top of the inner wall of the second gantry (11); the output end of the second servo motor (1202) is fixedly connected to a driving gear (1205); the outer surface of the driving gear (1205) is meshed with a driven gear (1206); the driven gear (1206) is fixedly sleeved on the outer surface of the driving nut (1201); and the second guide rod (1203) is fixedly mounted on the top of the splash-proof cover plate (4) and movably passes through the gantry.

10. The process for preparing a lithium alloy negative electrode for a solid-state battery by an electrodeposition method according to claim 9, characterized in that: The fixing mechanism (9) comprises an L-shaped frame (901) fixedly mounted on the top of the placement frame (8), the L-shaped frame (901) is provided with a threaded hole, the inner thread of the threaded hole is connected to a threaded rod three (902), the bottom end of the threaded rod three (902) is rotatably connected to an abutment block (903), and the top end of the threaded rod three (902) is fixedly connected to a hand wheel (904).

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