Lithium phosphate sputtering target material with conductivity and preparation method thereof

Abstract

The invention relates to the technical field of target materials and target material manufacturing, in particular to a lithium phosphate sputtering target material with conductivity and a preparation method thereof. The lithium phosphate sputtering target material with conductivity comprises the following preparation steps of powder preparation, back tube roughening treatment, plasma spraying, target material polishing and target material refinement, and the lithium phosphate sputtering target material prepared through the method has excellent density and low resistivity, can be well suitable for a subsequent sputtering process, and can be used for preparing the lithium phosphate sputtering target material with conductivity. And the requirement for reactive sputtering of a DC or MF power supply of a client can be met, and the application range is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of target materials and target material manufacturing, and in particular to a conductive lithium phosphate sputtering target material and a preparation method thereof. Background Art

[0002] All-solid-state thin-film lithium-ion batteries have received widespread attention at home and abroad in recent years due to their high power density, low self-discharge rate, excellent charge and discharge cycle performance, arbitrary shape and size design, no solution leakage, no explosion, and safe use. Some countries have achieved industrial production. This type of battery has shown broad application prospects both in civilian and military applications.

[0003] Lithium phosphate is the most stable and widely used solid electrolyte in solid-state thin-film batteries. Its preparation is the key to all-solid-state thin-film batteries, and the corresponding film performance directly determines the capacity and performance of the battery. Therefore, the quality of the target material is also particularly important.

[0004] Patent technology document CN201811447256.1 discloses a process for preparing sputtering targets based on plasma spraying technology. The process for preparing sputtering targets uses plasma spraying technology to prepare targets, and has a high density (relative density>93%) and a high purity comparable to that of the initial powder material. Compared with hot pressing or sintering methods, the preparation process of the present invention can not only meet the large-size target preparation requirements required for thin-film battery production, but also be used for target production of electrode materials. Lithium phosphate rotary sputtering target is a new type of sputtering target. As a good conductor for vacuum sputtering, thin films are prepared by magnetron sputtering to improve the energy storage and cycle times of all-solid-state thin-film lithium-ion batteries. The film layer has good density, but the conductivity of lithium phosphate targets is often poor, which is bound to affect the conductivity of subsequent sputtered films. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a conductive lithium phosphate sputtering target and a preparation method thereof, so as to solve the problem of poor conductivity of traditional lithium phosphate targets.

[0006] Based on the above purpose, the present invention provides a method for preparing a conductive lithium phosphate sputtering target, comprising the following steps:

[0007] (1) Powder preparation: lithium phosphate powder and conductive composite powder are mixed, ball-milled, and dried to obtain a mixed powder;

[0008] (2) Back tube roughening treatment: The back tube is subjected to surface treatment to obtain a back tube with a roughened surface;

[0009] (3) Plasma spraying: using a plasma sprayer, the mixed powder prepared in step (1) is evenly sprayed onto the back tube to obtain a crude target material;

[0010] (4) Target polishing: Use 60-400 mesh diamond abrasive belt to polish the surface of the rough target;

[0011] (5) Target finishing: Turn both ends of the polished target and finish it;

[0012] The preparation steps of the conductive composite powder are as follows:

[0013] Titanium, aluminum, tantalum powder and lithium phosphate powder are mixed, ball-milled, molded, sintered, crushed, and ground to obtain conductive composite powder;

[0014] The conductive powder has a porous structure, and the pore size thereof is 500nm-20μm.

[0015] Furthermore, the weight percentage of the lithium phosphate powder and the conductive composite powder in step (1) is 95%-98%: 2%-5%.

[0016] Furthermore, the particle size of the lithium phosphate powder in step (1) is 100-500 nm, and the purity is not less than 4N.

[0017] Furthermore, in step (1), the ball milling speed is 500-700 rpm and the time is 8-10 h.

[0018] Furthermore, the surface treatment in step (2) includes back tube sandblasting roughening treatment and back tube priming treatment.

[0019] Furthermore, the back tube priming treatment is performed by arc spraying.

[0020] Furthermore, the specific parameters of the plasma spraying in step (3) are powder feeding amount 10-100 g / min, argon flow rate 1000-5000 L / H, hydrogen flow rate 100-1500 L / H, and carrier gas flow rate 50-500 L / H.

[0021] Furthermore, the weight percentage of the titanium, aluminum, tantalum powder and lithium phosphate powder is 20%: 30-40%: 30%: 10-20%.

[0022] Furthermore, the forming is carried out by compression molding with a pressure of 20-40T.

[0023] Furthermore, the specific parameters of the sintering are keeping warm at 200° C. for 2 hours, keeping warm at 700° C. for 4 hours, keeping warm at 1000° C. for 4 hours, and finally keeping warm at 1450° C. for 4 hours.

[0024] Furthermore, the present invention also provides a conductive lithium phosphate sputtering target material, and the conductive lithium phosphate sputtering target material is prepared by the above-mentioned method for preparing the conductive lithium phosphate sputtering target material.

[0025] Beneficial effects of the present invention:

[0026] The present invention prepares the sputtering target material by plasma spraying. Compared with the traditional hot pressing sintering method for preparing the sputtering target material, the final product has high density, high purity and controllable size.

[0027] The present invention significantly improves the conductivity of the lithium phosphate target material by adding titanium, aluminum and tantalum powders into the lithium phosphate powder.

[0028] The present invention forms a powder with a porous structure by compounding titanium, aluminum, tantalum powder and lithium phosphate powder, and then mixes the powder with lithium phosphate powder, so that the density and conductivity of the lithium phosphate target are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description.

[0030] Figure 1 This is the conductive lithium phosphate sputtering target prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0032] Example 1: A conductive lithium phosphate sputtering target is prepared as follows:

[0033] (1) 20 g of titanium, 30 g of aluminum, 30 g of tantalum powder and 20 g of lithium phosphate powder were mixed, ball-milled, pressed at 20 ° C., then kept at 200 ° C. for 2 h, kept at 700 ° C. for 4 h, kept at 1000 ° C. for 4 h, and finally kept at 1450 ° C. for 4 h for sintering, crushing, and grinding to obtain a conductive composite powder;

[0034] (2) 95 g of lithium phosphate powder and 5 g of conductive composite powder were mixed, ball-milled at 500 rpm for 8 h, and dried to obtain a mixed powder;

[0035] (3) The back tube is first subjected to a surface roughening treatment by sandblasting, and then arc spraying is used for primer to obtain a surface roughened back tube;

[0036] (4) using plasma spraying technology, the mixed powder prepared in step (2) is evenly sprayed onto the surface roughened back tube to obtain a target rough product, wherein the plasma spraying powder feeding amount is 10 g / min, the argon flow rate is 1000 L / H, the hydrogen flow rate is 100-L / H, and the carrier gas flow rate is 50 L / H;

[0037] (5) Use a 60-mesh diamond abrasive belt to polish the surface of the rough target material, and finally turn both ends of the polished target material and perform fine finishing.

[0038] Example 2: A conductive lithium phosphate sputtering target material is prepared as follows:

[0039] (1) 20 g of titanium, 35 g of aluminum, 30 g of tantalum powder and 15 g of lithium phosphate powder were mixed, ball-milled, pressed at 30 °C, then kept at 200 °C for 2 h, kept at 700 °C for 4 h, kept at 1000 °C for 4 h, and finally kept at 1450 °C for 4 h for sintering, crushing, and grinding to obtain a conductive composite powder;

[0040] (2) 97 g of lithium phosphate powder and 3 g of conductive composite powder were mixed, ball-milled at 600 rpm for 9 h, and dried to obtain a mixed powder;

[0041] (3) The back tube is first subjected to a surface roughening treatment by sandblasting, and then arc spraying is used for primer to obtain a surface roughened back tube;

[0042] (4) using plasma spraying technology to evenly spray the mixed powder prepared in step (2) onto the surface roughened back tube to obtain a target rough product, wherein the plasma spraying powder feeding amount is 60 g / min, the argon flow rate is 3000 L / H, the hydrogen flow rate is 1000 L / H, and the carrier gas flow rate is 300 L / H;

[0043] (5) Use a 200-mesh diamond abrasive belt to polish the surface of the rough target material, and finally turn both ends of the polished target material and perform fine finishing.

[0044] Example 3: A conductive lithium phosphate sputtering target is prepared as follows:

[0045] (1) 20 g of titanium, 40 g of aluminum, 30 g of tantalum powder and 10 g of lithium phosphate powder were mixed, ball-milled, pressed at 30 °C, then kept at 200 °C for 2 h, kept at 700 °C for 4 h, kept at 1000 °C for 4 h, and finally kept at 1450 °C for 4 h for sintering, crushing, and grinding to obtain a conductive composite powder;

[0046] (2) 95 g of lithium phosphate powder and 5 g of conductive composite powder were mixed, ball-milled at 650 rpm for 10 h, and dried to obtain a mixed powder;

[0047] (3) The back tube is first subjected to a surface roughening treatment by sandblasting, and then arc spraying is used for primer to obtain a surface roughened back tube;

[0048] (4) using plasma spraying technology, the mixed powder prepared in step (2) is evenly sprayed onto the surface roughened back tube to obtain a target rough product, wherein the plasma spraying powder feeding amount is 90 g / min, the argon flow rate is 4000 L / H, the hydrogen flow rate is 1500 L / H, and the carrier gas flow rate is 400 L / H;

[0049] (5) Use a 300-mesh diamond abrasive belt to polish the surface of the rough target material, and finally turn both ends of the polished target material and perform fine finishing.

[0050] Example 4: A conductive lithium phosphate sputtering target is prepared as follows:

[0051] (1) 20 g of titanium, 40 g of aluminum, 30 g of tantalum powder and 10 g of lithium phosphate powder were mixed, ball-milled, pressed at 40 °C, then kept at 200 °C for 2 h, kept at 700 °C for 4 h, kept at 1000 °C for 4 h, and finally kept at 1450 °C for 4 h for sintering, crushing, and grinding to obtain a conductive composite powder;

[0052] (2) 98 g of lithium phosphate powder and 2 g of conductive composite powder were mixed, ball-milled at 700 rpm for 10 h, and dried to obtain a mixed powder;

[0053] (3) The back tube is first subjected to a surface roughening treatment by sandblasting, and then arc spraying is used for primer to obtain a surface roughened back tube;

[0054] (4) using plasma spraying technology to evenly spray the mixed powder prepared in step (2) onto the surface roughened back tube to obtain a rough target material, wherein the plasma spraying powder feeding amount is 100 g / min, the argon flow rate is 5000 L / H, the hydrogen flow rate is 1500 L / H, and the carrier gas flow rate is 500 L / H;

[0055] (5) Use a 400-mesh diamond abrasive belt to polish the surface of the rough target material, and finally turn both ends and fine-tune the polished target material.

[0056] Comparative Example 1: A lithium phosphate sputtering target material, which is specifically prepared as follows:

[0057] (1) 20 g of titanium, 35 g of aluminum, and 30 g of tantalum powder were mixed and ball-milled to obtain a conductive mixed powder;

[0058] (2) 97 g of lithium phosphate powder and 3 g of conductive mixed powder were mixed, ball-milled at 600 rpm for 9 h, and dried to obtain a mixed powder;

[0059] (3) The back tube is first subjected to a surface roughening treatment by sandblasting, and then arc spraying is used for primer to obtain a surface roughened back tube;

[0060] (4) using plasma spraying technology to evenly spray the mixed powder prepared in step (2) onto the surface roughened back tube to obtain a target rough product, wherein the plasma spraying powder feeding amount is 60 g / min, the argon flow rate is 3000 L / H, the hydrogen flow rate is 1000 L / H, and the carrier gas flow rate is 300 L / H;

[0061] (5) Use a 200-mesh diamond abrasive belt to polish the surface of the rough target material, and finally turn both ends of the polished target material and perform fine finishing.

[0062] Comparative Example 2: A lithium phosphate sputtering target material, which is specifically prepared as follows:

[0063] (1) 97 g of lithium phosphate powder, 0.71 g of titanium, 1.24 g of aluminum, and 1.05 g of tantalum powder were mixed, ball-milled at 600 rpm for 9 h, and dried to obtain a mixed powder;

[0064] (2) The back tube is first subjected to a surface roughening treatment by sandblasting, and then arc spraying is used for primer to obtain a surface roughened back tube;

[0065] (3) using plasma spraying technology, the mixed powder prepared in step (1) is evenly sprayed onto the surface roughened back tube to obtain a target rough product, wherein the plasma spraying powder feeding amount is 60 g / min, the argon flow rate is 3000 L / H, the hydrogen flow rate is 1000 L / H, and the carrier gas flow rate is 300 L / H;

[0066] (4) Use a 200-mesh diamond abrasive belt to polish the surface of the rough target material, and finally turn both ends of the polished target material and perform fine finishing.

[0067] Comparative Example 3: A lithium phosphate sputtering target material, which is specifically prepared as follows:

[0068] (1) ball milling 100 g of lithium phosphate powder at 600 rpm for 9 h and drying to obtain a mixed powder;

[0069] (2) The back tube is first subjected to a surface roughening treatment by sandblasting, and then arc spraying is used for primer to obtain a surface roughened back tube;

[0070] (3) using plasma spraying technology, the mixed powder prepared in step (1) is evenly sprayed onto the surface roughened back tube to obtain a target rough product, wherein the plasma spraying powder feeding amount is 60 g / min, the argon flow rate is 3000 L / H, the hydrogen flow rate is 1000 L / H, and the carrier gas flow rate is 300 L / H;

[0071] (4) Use a 200-mesh diamond abrasive belt to polish the surface of the rough target material, and finally turn both ends of the polished target material and perform fine finishing.

[0072] Performance Testing

[0073] Density: obtained by drainage method, the test results are shown in Table 1;

[0074] Resistivity: The four-probe method was used for testing. The test results are shown in Table 1.

[0075] Table 1 Performance test results

[0076]

[0077]

[0078] Data analysis shows that the conductive lithium phosphate sputtering target of the present invention has excellent compactness and low resistivity, and its density is not less than 4.3 g / cm 3 , the resistivity is not higher than 1Ω·cm, which is well suitable for the subsequent sputtering process, so that the sputtered film has excellent conductivity.

[0079] It can be seen from Example 2 and Comparative Examples 1-3 in Table 1 that the present invention greatly improves the conductivity of the lithium phosphate target by adding titanium, aluminum and tantalum powders to the lithium phosphate powder, and the conductivity of the lithium phosphate target obtained by compounding titanium, aluminum, tantalum powders and lithium phosphate powder to form a powder with a porous structure and mixing it with lithium phosphate powder is further improved. This is probably because the porous structure provides a larger specific surface area, and the pre-mixing improves the compatibility between the raw materials, thereby improving the density thereof, and the evenly dispersed titanium, aluminum and tantalum powders can form an interconnected conductive network, thereby further improving its conductivity.

[0080] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A method for preparing a conductive lithium phosphate sputtering target, characterized in that: The following steps are involved: (1) Powder preparation: lithium phosphate powder and conductive composite powder are mixed, ball-milled, and dried to obtain a mixed powder; (2) Back tube roughening treatment: The back tube is subjected to surface treatment to obtain a back tube with a roughened surface; (3) Plasma spraying: using a plasma sprayer, the mixed powder prepared in step (1) is evenly sprayed onto the backing tube to obtain a crude target material; (4) Target polishing: Use a 60-400 mesh diamond abrasive belt to polish the surface of the rough target; (5) Target finishing: Turn both ends of the polished target and finish it; The preparation steps of the conductive composite powder are as follows: Titanium, aluminum, tantalum powder and lithium phosphate powder are mixed, ball-milled, molded, sintered, crushed, and ground to obtain conductive composite powder; The conductive composite powder has a porous structure with a pore size of 500nm-20μm.

2. The method for preparing a conductive lithium phosphate sputtering target according to claim 1, characterized in that: The weight percentages of the lithium phosphate powder and the conductive composite powder in step (1) are 95%-98%: 2%-5%.

3. The method for preparing a conductive lithium phosphate sputtering target according to claim 1, characterized in that: The particle size of the lithium phosphate powder in step (1) is 100-500 nm, and the purity is not less than 4N.

4. The method for preparing a conductive lithium phosphate sputtering target according to claim 1, characterized in that: The surface treatment in step (2) includes back tube sandblasting roughening treatment and back tube priming treatment.

5. The method for preparing a conductive lithium phosphate sputtering target according to claim 1, characterized in that: The specific parameters of the plasma spraying in step (3) are powder feeding amount 10-100 g / min, argon flow rate 1000-5000 L / H, hydrogen flow rate 100-1500 L / H, and carrier gas flow rate 50-500 L / H.

6. The method for preparing a conductive lithium phosphate sputtering target according to claim 1, characterized in that: The weight percentages of the titanium, aluminum, tantalum powder and lithium phosphate powder are 20%: 30-40%: 30%: 10-20%.

7. The method for preparing a conductive lithium phosphate sputtering target according to claim 1, characterized in that: The molding is performed by compression molding with a pressure of 20-40T.

8. The method for preparing a conductive lithium phosphate sputtering target according to claim 1, characterized in that: The specific parameters of the sintering are: keeping at 200° C. for 2 hours, keeping at 700° C. for 4 hours, keeping at 1000° C. for 4 hours, and finally keeping at 1450° C. for 4 hours.

9. A conductive lithium phosphate sputtering target, characterized in that: The conductive lithium phosphate sputtering target is prepared by the method for preparing a conductive lithium phosphate sputtering target according to any one of claims 1 to 8.

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