CN103268954B - LiSiPON (lithium silicon phosphorus) lithium-ion battery solid electrolyte film, and preparation method and application thereof - Google Patents

Abstract

The invention discloses a preparation method of a LiSiPON lithium ion battery solid electrolyte film. It is a LiSiPON film with a thickness of 80nm~150nm obtained by bombarding Li ₃ PO ₄ and Si ₃ N ₄ with an ion beam with a volume flow ratio of N 2 : Ar of 1: _5-1 . The invention also discloses the application of the LiSiPON lithium-ion battery solid-state electrolyte film in the preparation of miniature all-solid-state lithium battery materials. Through experiments, it is found that increasing the ratio of N ₂ can effectively increase the nitrogen content in the film, and when the optimal ratio: the flow ratio of nitrogen and argon is 1:1, the ion conductivity can reach 6.8×10 ^-6 S/cm. Combined with thin-film electrodes, it can be assembled into an all-solid-state thin-film lithium-ion battery. The method of the present invention not only has low cost and simple process, but also the prepared thin film is dense and uniform, and the preparation conditions are highly controllable, which is convenient for large-scale commercial production.

Description

LiSiPON lithium ion battery solid electrolyte film and its preparation method and application

technical field

The invention belongs to the technical field of all-solid-state thin-film lithium-ion batteries. In particular, it involves the preparation of LiSiPON by ion beam assisted deposition (IBAD), using low-energy nitrogen ions to bombard a composite target composed of Li ₃ PO ₄ and Si ₃ N ₄ to obtain an electrolyte film with high nitrogen content.

Background technique

With the continuous development of electronic devices in the direction of miniaturization and light weight, there is an urgent need for micro-sized chemical power sources to match them. Especially for the development of Micro-Electronic Mechanical Systems (MEMS) technology, micro-batteries have attracted people's attention. The series of micro batteries that have been researched so far include: micro zinc-nickel batteries, micro all-solid lithium batteries, micro solar cells, micro thermoelectric batteries, micro fuel cells, etc. Among them, the miniature all-solid-state lithium battery is considered to be one of the most suitable power sources, because lithium is the lightest metal element and has the largest electronegativity, which can provide high specific energy. This kind of battery is expected to be used in small satellites, portable electronic equipment space technology, defense industry and so on. Due to its advantages of high specific energy, good cycle performance and high safety, all-solid-state thin-film lithium batteries meet the requirements of energy miniaturization and light weight, and have gradually become a research hotspot.

As the key material of all-solid-state thin-film lithium-ion batteries, the solid-state electrolyte film is between the positive and negative electrodes and is the medium for transferring ions. Therefore, it must have high ionic conductivity, low electronic conductivity, wide electrochemical window and The positive and negative electrodes have good stability. Many electrode film materials for all-solid-state thin-film lithium batteries have been reported at home and abroad, but the research on electrolyte films lags behind electrode films. This has become a heavy fetter that restricts the further improvement and improvement of all-solid-state thin-film lithium batteries and moves from the laboratory to the market. Therefore, the development of high-performance, low-cost electrolyte films is of great significance for the development of all-solid-state thin-film batteries.

In 1992, Bates et al. of Oak Ridge National Laboratory reported for the first time a relatively stable amorphous inorganic thin film electrolyte material LiPON (Lithium phosphorous oxynitride), which played a very important role in improving the performance of thin film lithium batteries. role. LiPON has good electrochemical stability, and the room temperature electrochemical window (VS. Li) can reach more than 5.5V. Such a wide electrochemical window is very convenient for charging and discharging in practical applications; There is no phase change in the range of 247-413K; the electronic conductivity is lower than 10 ^-14 S/cm, and the self-discharge of LiPON-based thin-film batteries is negligible when stored for 12 months. In addition to its high electrochemical stability, LiPON also has particularly high mechanical stability. During the cycle, it will not appear dendrites, cracking, or powdering like cathode materials. Generally, LiPON is obtained by magnetron sputtering Li ₃ PO ₄ target under N ₂ atmosphere. The chemical composition of LiPON obtained under different experimental conditions is different, and it is concluded that the conductivity of the film increases with the pressure of N ₂ in the reaction atmosphere or the N in LiPON increase with increasing content. South Korea SJLee et al. used (1-x)Li ₃ PO ₄ ·xLi ₂ SiO ₃ as the target material to prepare Li-Si-PON oxynitride thin film electrolyte by radio frequency magnetron sputtering under nitrogen atmosphere. The study found that with the increase of Si content, the ionic conductivity of the film increased, up to 1.24×10 ^-5 S/cm. Since the ion beam assisted deposition can precisely control the beam intensity and beam energy, a thin film with a higher nitrogen content can be obtained, thereby further improving the ion conductivity. Therefore, the article uses a Kaufmann ion source to bombard Li ₃ PO ₄ and Si ₃ N ₄ composite targets with low-energy ion beams to prepare LiSiPON.

Contents of the invention

In the present invention, the nitrogen content is increased by designing a composite target, and a Li ₃ PO ₄ round target with a diameter of 50.8 mm is fixed on a Si ₃ N ₄ square target with a side length of 69.5 mm. The use of Si ₃ N ₄ can effectively introduce Si elements without other effects on the film composition, and N can be sputtered from the target, which can increase the nitrogen content in the film. Due to the addition of Si, the cross-linked structure of LiPON is changed, and the stability and ionic conductivity of the film are further improved. LiSiPON thin film has excellent stability, electrochemical performance, and low cost, no pollution to the environment. These excellent properties make it a very potential thin-film battery electrolyte material, which has great social and potential economic benefits in the field of new energy materials.

To achieve the above object, the present invention discloses a LiSiPON lithium ion battery solid electrolyte film. At the same time, the preparation method of LiSiPON thin film is also disclosed. Technical content of the present invention is as follows:

A LiSiPON lithium-ion battery solid electrolyte film, characterized in that it is bombarded by ion beams with a N ₂ : Ar volume flow ratio of 1:5-1 on Li ₃ PO ₄ and Si ₃ N ₄ , and the obtained thickness is 80nm~150nm LiSiPON film.

The LiSiPON lithium-ion battery solid electrolyte film of the present invention preferably has a volume ratio of nitrogen and argon flow of 1:1.

The present invention further discloses a preparation method of LiSiPON lithium-ion battery solid electrolyte film, which is characterized in that it is carried out according to the following steps:

(1) Before depositing the film, fix the circular Li ₃ PO ₄ target on the square Si ₃ N ₄ target, sputter the synthesized target with Ar ⁺ , and use N ⁺ for auxiliary bombardment;

(2) Thin films were deposited on single-sided polished (100) single-crystal silicon wafer substrates. Mechanical pumps and molecular pumps were used to control the background vacuum of 2.8×10 ^-4 Pa~3.0×10 ^-4 Pa during the experiment. Measured by the ionization gauge, pure N ₂ and Ar ₂ are selected as the sputtering gas during the deposition process, and the flow rate is controlled by a mass flow controller to be 3 standard milliliters/minute (sccm)~6 standard milliliters/minute (sccm); the deposition process The total working pressure is 1.0×10 ^-2 Pa~1.2×10 ^-2 Pa;

(3) Experimentally control the flow ratio of N ₂ and Ar at 1:5~1:1.

The (100) single-crystal silicon wafer of the single-side polishing of the present invention is first cleaned with acetone and ethanol ultrasonically for 15 minutes, and sent into the vacuum deposition chamber immediately after drying; Ar ⁺ cleans the sample for 5 min~10min. When depositing a thin film, adjust the nitrogen-argon ratio and accurately control the sputtering time of each sample. The process parameters of the sputtering ion source: sputtering energy 0.9keV~1.1keV, sputtering beam current 15mA~20mA.

The preparation method of a preferred LiSiPON lithium-ion battery solid-state electrolyte film of the present invention is as follows:

Using the ion beam-assisted deposition equipment in the FJL560CIZ ultra-high vacuum magnetron and ion beam combined sputtering system, before depositing the thin film, the circular Li ₃ PO ₄ is fixed on the square Si ₃ N ₄ target, placed in the equipment for sputtering The location of the target. When depositing thin films, the computer program can be used to accurately control the sputtering time of the target. The substrate is a single-sided polished (100) single-crystal silicon wafer, which is ultrasonically cleaned with acetone and absolute ethanol for 15 minutes before film formation, and placed on a rotatable sample stage after drying. The background vacuum is up to 2.8×10 ^-4 Pa during film coating, while the Ar ⁺ sputtering target is supplemented by low energy N ⁺ bombardment, the total working pressure is kept at 1.2×10 ^-2 Pa during the whole deposition process. Sputtering ion source process parameters: sputtering energy 1.1keV, sputtering beam current 20mA. Control the flow rate of the incoming gas to control the flow ratio of N ₂ and Ar to be 1:1, choose pure N ₂ and Ar ₂ as the sputtering gas, and use a mass flow controller to control the flow of N ₂ to 2 sccm and the flow of Ar to 2 sccm. The sputtering time is 2h, and the thickness of the film is about 100nm.

The preparation method of another preferred LiSiPON lithium-ion battery solid-state electrolyte film of the present invention is as follows:

Using the ion beam-assisted deposition equipment in the FJL560CIZ ultra-high vacuum magnetron and ion beam combined sputtering system, before depositing the thin film, the circular Li ₃ PO ₄ is fixed on the square Si ₃ N ₄ target, placed in the equipment for sputtering The position of the target. When depositing thin films, the computer program can be used to accurately control the sputtering time of the target. The substrate is a single-sided polished (100) single-crystal silicon wafer, which is ultrasonically cleaned with acetone and absolute ethanol for 15 minutes before film formation, and placed on a rotatable sample stage after drying. When coating, the background vacuum is higher than 3×10 ^-4 Pa, while the Ar ⁺ sputtering target is assisted with low-energy N ⁺ bombardment, the total working pressure is kept at 1.2×10 ^-2 Pa throughout the deposition process. Sputtering ion source process parameters: sputtering energy 1.1keV, sputtering beam current 20mA. Control the flow rate of the incoming gas to control the flow ratio of N ₂ and Ar to be 1:2, select pure N ₂ and Ar ₂ as the sputtering gas, and use a mass flow controller to control the flow of N ₂ to 1 sccm and the flow of Ar to 2 sccm. The sputtering time is 2h, and the thickness of the film is about 100nm.

The method of LiSiPON film test prepared by the present invention is as follows:

The invention makes full use of the bombardment effect of the ion beam, precisely controls the composition of the film, and obtains a smooth and dense film. In this experiment, thin films were prepared under three different ratios of nitrogen and argon, and structural tests, stability tests and electrochemical tests were carried out. The experimental results under each condition were obtained and a series of performance analyzes were carried out, and the nitrogen-argon ratio with better electrochemical performance was obtained. The present invention carries out X-ray diffraction (XRD) structure analysis, X-ray energy dispersive spectrum (EDS) analysis, X-ray photoelectron energy spectrum (XPS) analysis to the synthetic thin film, adopts vacuum tube furnace (OTF-1200X) to test thin film in different Stability under oxygen concentration, using electrochemical workstation for AC impedance test.

The invention relates to the use of ion beam assisted deposition technology (IBAD), design and use of composite targets to prepare a new type of thin film lithium electrolyte film, the conductivity of lithium ions can reach 6.8×10 ^-6 S/cm, and use ion beam assisted deposition technology to control The purpose of feeding gas nitrogen and argon flow ratio is to find the relationship between gas flow and nitrogen content in the film. Bombard a composite target composed of Li ₃ PO ₄ and Si ₃ N ₄ with Ar ⁺ , and deposit thin films on a single-sided polished Si (100) substrate, using mechanical pumps and molecular pumps, with a background vacuum of 2.8×10 ^-4 Pa~3.0 ×10 ^-4 Pa, the pressure value is measured by the ionization gauge, and the sputtering gas used in the deposition process is pure Ar and N ₂ . The mass flow controller is used to control the flow rate to 3sccm~6 sccm; the working pressure during the deposition process is about 1.2×10 ^-2 Pa, and the process parameters of the sputtering ion source are: sputtering energy 0.9keV~1.1keV, sputtering beam current 15mA~ 20mA. Its process parameters: discharge voltage: 40V~45V, discharge current: 0.4A~0.8A, filament current: 6A~8A, acceleration voltage: 190V ~200V, acceleration current: 1mA ~4mA.

Results of the tests of the present invention:

Figure 1 is a schematic diagram of a composite target composed of Li ₃ PO ₄ and Si ₃ N ₄ , Figure 2 is a schematic diagram of the Au/LiSiPON/Au sandwich structure (top view and side view), which is used for the determination of ionic conductivity; Figure 3 is LiSiPON The XRD diffraction pattern of the film shows that the main form of the film is amorphous, and there are more gaps in the framework of the amorphous film to facilitate the transport and conduction of lithium ions; Elemental analysis, the figure shows that the bombardment of low-energy nitrogen ions effectively implants N and Si into the film. When the nitrogen-argon ratio is 1:1, the nitrogen content in the film is the highest, followed by the nitrogen-argon ratio of 1:2; Figure 5 Electrolyte From the XPS spectrum of the film, it can be seen that N has entered into the Li ₃ PO ₄ molecular framework, and the formation of interlaced P—N< structure contributes to the improvement of the mobility of Li ⁺ ; Figure 6 shows the AC impedance spectrum of 1# , the relatively high nitrogen content is beneficial to improve its ionic conductivity.

The performance of the LiSiPON film product prepared by the present invention is as follows:

Through experiments, it is found that increasing the amount of N ₂ can effectively increase the nitrogen content in the film, and the films under different conditions all contain a large amount of Si. And when the optimal ratio: the flow ratio of nitrogen and argon is 1:1, the ion conductivity can reach 6.8×10 ^-6 S/cm. The prepared LiSiPON film changes the distribution of orthophosphate anions and forms an interlaced interconnection structure due to the introduction of Si and N. The skeleton of the amorphous film has more voids to facilitate the movement and conduction of lithium ions, reducing the activation energy of lithium ion migration. Thereby improving the lithium ion conductivity.

The above results prove that the "thin-film lithium electrolyte LiSiPON prepared by ion beam assisted deposition technology" of the present invention has good electrochemical properties, further optimizes the manufacturing process, improves the performance of the film, and will have important application prospects in the further development of all-solid-state thin-film batteries .

The invention further discloses the application of the LiSiPON lithium-ion battery solid-state electrolyte film in the preparation of miniature all-solid-state lithium battery materials.

The miniaturization of a large number of portable consumer electronic devices, such as mobile phones, cameras and notebook computers, urgently requires the development of matching thin-film batteries. The results obtained in thin film electrode materials are relatively abundant, while the research on electrolyte materials is slightly inferior. The preparation method of LiSiPON provided by the invention can be applied to all solid-state thin-film lithium batteries as an electrolyte film. This method uses ion beam assisted deposition to effectively avoid the situation that magnetron sputtering coating is easy to cause uneven heating and cracking of the target, while electron beam evaporation coating needs to use tungsten boat to melt Li ₃ PO ₄ raw material, which will introduce tungsten element Pollution; and the preparation process is easy to control and has no pollution to the environment, which is of great significance to actual production. At the same time, a film with a high nitrogen content can be obtained by bombarding with a low-energy nitrogen ion beam. By simply superimposing the target material and doping silicon, the ion conductivity of the electrolyte film is effectively improved. The lithium ion conductivity measured by the AC impedance technique is 6.8×10 ^-6 S/cm, higher than the ionic conductivity of LiPON prepared by JBBates et al. using magnetron sputtering. Due to the incorporation of Si, the stability of the film has been improved, the physical and chemical properties have been significantly improved, and the cost is low. It is expected to be put into use in the commercial production of thin film batteries in the future.

Description of drawings

Figure 1: Schematic diagram of the composite target composed of Li ₃ PO ₄ and Si ₃ N ₄ in this series;

Figure 2: Schematic diagram of the Au/LiSiPON/Au sandwich structure in this series (top view and side view);

Figure 3: XRD diffraction patterns of LiSiPON films in this series;

Figure 4: Energy dispersive spectrum and element content table of LiSiPON thin films in this series;

Figure 5: XPS spectra of LiSiPON films in this series;

Figure 6: AC impedance spectrum of Au/ LiSiPON /Au in this series;

Figure 7: FJL560CI2 ultra-high vacuum RF magnetron and ion beam combined sputtering system;

1. Molecular pump, 2. Rotatable water-cooled target platform, 3. Li ₃ PO ₄ and Si ₃ N ₄ targets, 4. Auxiliary target, 5. Sputtering ion source, 6. Low energy auxiliary bombardment source, 7. Gas inlet , 8. Sample baffle, 9. Rotatable water-cooled sample stage, 10. Sample.

Detailed ways:

The present invention will be further described below in conjunction with specific examples, and the following examples are only used to illustrate the present invention rather than limit the present invention.

In order to further understand the content, characteristics and effects of the present invention, the description is as follows in conjunction with the accompanying drawings:

Equipment used: FJL560CI2 ultra-high vacuum radio frequency magnetron and ion beam combined sputtering system is used to synthesize LiSiPON electrolyte thin film. This system is jointly developed by Tianjin Normal University and Shenyang Scientific Instrument Factory of Chinese Academy of Sciences. Its structure is shown in Figure 7. The sputtering target is a 99.99% high-purity circular Li ₃ PO ₄ target with a diameter of 50.9 mm and a thickness of 3 mm, and a 99.99% high-purity square Si ₃ N ₄ target with a side length of 69.5×69.5 mm and a thickness of 3 mm. The circular Li ₃ PO ₄ target was fixed on the square Si ₃ N ₄ target to form a composite target. The sample is placed on the controllable sample rotating turntable sample stage 10 in the vacuum chamber; the pumping system is completed by the mechanical pump and the HTFB turbomolecular pump 1, the air pressure value is measured by the ionization gauge, Ar enters the vacuum chamber through the gas inlet 7, and the Ar And the intake flow of _N2 is controlled by mass flow meter. A computer program precisely controls the sputtering time for each sample. The same bombardment energy and ion source parameters were used for different samples.

Specific synthetic process parameters:

The N ₂ flows are: 2sccm, 1sccm, 0.4sccm; the Ar flow is kept at 2sccm; (Nitrogen and Argon ratios are 1:1, 1:2, 1:5). Background vacuum: 2.8×10 ^-4 Pa; working pressure: 0.012 Pa; sputtering ion source process parameters: sputtering energy 1.1keV, sputtering beam current 20mA. Its process parameters: discharge voltage: 40V, discharge current: 0.8A, filament current: 7A, acceleration voltage: 200V, acceleration current: 4mA. It should be noted that other models of ion beam assisted deposition (IBAD) equipment can be used.

Example 1

Synthesize LiSiPON electrolyte film by adjusting Ar, _N flow ratio:

(1) Before the experiment, the Si wafer was ultrasonically cleaned with acetone and absolute alcohol for 15 min, dried and put into the coating chamber.

(2) Fix the circular Li ₃ PO ₄ target on the square Si ₃ N ₄ target, place it on the target platform A in the vacuum chamber, and evacuate the chamber so that the background vacuum in the chamber is 2.8×10 ^{- 4Pa} .

(3) Use a mass flow meter to control the Ar intake flow rate to keep it at about 20 sccm, turn on the ion gun power supply, sputtering energy 500eV, sputtering beam current 20mA, and accelerating current 5mA. Bombard the samples for at least 5 min. Power off the ion gun.

(4) Turn on the sputtering ion source, control the Ar intake flow rate with a mass flow meter to keep it at about 2 sccm, open the N ₂ intake valve, and control the flow rate to 2 sccm, 1 sccm, and 0.4 sccm respectively, and the corresponding sample is 1# , 2#, 3#. The sputtering energy is 1.1keV, and the sputtering beam current is 20mA. The accelerating voltage is 200V, and the accelerating current is 4mA.

(5) At this time, keep the working air pressure at about 0.012 Pa. The sputtering time of each sample was controlled by a computer program to be 2 hours. Films of different samples can be obtained by changing the ratio of the gas flow rate of each sample.

(6) The film is in the high vacuum chamber, and the chamber is not opened until the temperature drops below 100°C.

Synthesize LiSiPON electrolyte film by adjusting Ar, _N flow ratio:

Deposition parameters: N ₂ flow rate: 2sccm, 1sccm, 0.4sccm; Ar flow rate maintained at 2sccm; background vacuum: 2.8×10 ^-4 Pa; working pressure: 0.012 Pa; sputtering ion source process parameters: sputtering energy 1.1keV, sputtering beam current 20mA. Its process parameters: discharge voltage: 40V, discharge current: 0.8A, filament current: 7A, acceleration voltage: 200V, acceleration current: 4mA. The deposition time is controlled at about 7200s.

For the optimal conditions, the preparatory work before the experiment is as described in steps (1) to (3), and then as shown in step (4), change the ratio of nitrogen to argon to deposit films with different nitrogen contents. The obtained film was stored in a dry box for testing of film thickness, structure, element content, etc.

Example 2

For the purpose of measuring the ionic conductivity of the thin film electrolyte, Au, LiSiPON film and Au were sequentially deposited on the Si(100) substrate to form an Au/LiSiPON/Au "sandwich" structure (as shown in Figure 2). The specific implementation steps are as follows:

(1) Before the experiment, the sputtering target was adjusted to the Au target, and the Si wafer was ultrasonically cleaned with acetone and absolute alcohol for 15 min, dried and put into the coating chamber.

(2) Vacuum the chamber so that the background vacuum in the chamber is 2.8×10 ^-4 Pa.

(3) Use a mass flow meter to control the Ar intake flow rate to keep it at about 20 sccm, turn on the ion gun power supply, sputtering energy 500eV, sputtering beam current 20mA, and accelerating current 5mA. Bombard the samples for at least 5 min. Power off the ion gun.

(4) Turn on the sputtering ion source, and use a mass flow meter to control the Ar intake flow to keep it at about 20 sccm. The sputtering energy is 1keV, and the sputtering beam current is 20mA. The accelerating voltage is 200V, and the accelerating current is 2mA. Sputtering time is 1h.

(5) Adjust the sputtering target to the composite target of Li ₃ PO ₄ and Si ₃ N ₄ (as described in Example 1), turn on the sputtering ion source, adjust the flow rate of Ar to 2 sccm, and the flow rate of N ₂ to 2 sccm, and sputter The energy is 1.1keV, and the sputtering beam current is 20mA. The accelerating voltage is 200V, and the accelerating current is 4mA. Sputtering time is 2h.

(6) The sputtering target position is adjusted to the Au target by computer control, the sputtering ion source is turned on, and the Ar flow rate is controlled to 20 sccm. The sputtering energy is 1keV, and the sputtering beam current is 20mA. The accelerating voltage is 200V, and the accelerating current is 2mA. Sputtering time is 1h.

(7) The film is in the high vacuum chamber, and the chamber is not opened until the temperature drops below 100°C.

The present invention uses the nanomechanical testing system of MTS, X-ray diffraction (XRD) instrument, X-ray energy dispersive spectrum (EDS) analyzer, and X-ray photoelectron spectroscopy (XPS) analysis for the films synthesized under various process conditions. The physical properties including film thickness, structure, chemical composition and element content were characterized by the instrument. In the experiment, the Princeton VersaSTAT4 multifunctional electrochemical workstation was used to conduct AC impedance analysis on the LiSiPON film, and the measurement frequency was from 0.1 Hz to 100 KHz. The test data results are shown in the table below, the main results are as follows:

1. In terms of physical properties: LiSiPON thin film, like LiPON, presents an amorphous structure. Increasing the amount of N ₂ can effectively increase the nitrogen content in the film, and the films under different conditions all contain a lot of Si. XPS patterns show that N presents two different structures in the film.

2. In terms of chemical properties: films with relatively high nitrogen content have relatively high ionic conductivity, which is 6.8×10 ^-6 S/cm. The introduction of N improves the ionic conductivity of the original system. As N ₂ The increase of the flow rate, the simultaneous increase of the N content and the ionic conductivity in the electrolyte film further confirmed that the nitrogen content in the film affects the transport and migration of lithium ions, thereby affecting the conductivity.

In general: The composite target composed of Li ₃ PO ₄ and Si ₃ N ₄ can be bombarded with low-energy nitrogen ions to obtain a dense and uniform thin film electrolyte LiSiPON. The test of structural composition and chemical composition proves that the N content in the film is proportional to the N ₂ flow rate. In direct proportion, the doping of N and Si is beneficial to the improvement of electrical conductivity. When the N ₂ :Ar ratio is 1:1, the nitrogen content in the film is the highest, and the ion conductivity can reach 6.8×10 ^-6 S/cm, which provides a basis for the application of thin film lithium-ion batteries. Further, the electrolyte film with excellent physical and electrochemical properties can be prepared by controlling the process parameters.

Example 3

Application of LiSiPON as Electrolyte Film in All-Solid Thin Film Lithium Batteries

Preparation of LiCoO ₂ /LiSiPON/Li All-Solid Thin Film Battery

(1) LiCoO ₂ thin film electrodes were plated on Si(110) substrates by radio frequency magnetron sputtering before the experiment, and the sputtering time was 4h.

(2) Use ion beam assisted deposition equipment to coat thin film electrolyte, adjust the sputtering target to Li ₃ PO ₄ and Si ₃ N ₄ composite target (as described in Example 1), and vacuum the chamber to make the The background vacuum is 2.8×10 ^-4 Pa.

(3) Turn on the sputtering ion source, adjust the Ar flow rate to 2 sccm, the N ₂ flow rate to 2 sccm, the sputtering energy to 1.1keV, and the sputtering beam current to 20mA. The accelerating voltage is 200V, and the accelerating current is 4mA. Sputtering time is 5h.

(4) The film is in the high vacuum chamber, and the chamber is not opened until the temperature drops below 100°C.

(5) Place the thin film in a vacuum thermal evaporation equipment, and vapor-deposit metal lithium thin-film electrodes for 1 h.

(6) Use RF magnetron sputtering to sputter Li ₃ PO ₄ film on the film as a protective layer for about 1h. So far assembled into a complete all-solid-state thin-film lithium-ion battery.

The LiSiPON film prepared by the ion beam assisted deposition (IBAD) method disclosed and proposed by the present invention can obtain an electrolyte film with better electrochemical performance under the condition of a suitable nitrogen-argon gas flow ratio, and the ion conductivity can reach 6.8×10 ^{- 6} S/cm, which can be applied to the preparation of thin-film lithium-ion batteries.

Those skilled in the art can realize it by referring to the content of this article and appropriately changing the raw materials and process parameters. The methods and products of the present invention have been described through preferred implementation examples, and those skilled in the art can obviously make changes or appropriate changes and combinations to the methods and products described herein without departing from the content, spirit and scope of the present invention to realize The technology of the present invention. In particular, it should be pointed out that all similar substitutions and modifications will be obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the present invention.

Claims (3)

1. a preparation method for LiSiPON lithium ion battery solid electrolyte film, is characterized in that being undertaken by following step:

(1) before deposit film, by circular Li ₃pO ₄target is fixed on square Si ₃n ₄above target, use Ar ⁺sputtering synthesis target, uses N simultaneously ⁺carry out auxiliary bombardment;

(2) deposit film in (100) monocrystalline silicon piece substrate of single-sided polishing, adopt mechanical pump and molecular pump, during Control release, base vacuum is 2.8 × 10 ^-4pa ~ 3.0 × 10 ^-4pa, atmospheric pressure value is measured by ionization gauge, and in deposition process, sputter gas selects pure N ₂, Ar, controlling its flow with mass flow controller is 3 standard milliliters/minute (sccm) ~ 6 standard milliliters/minute (sccm); Operating air pressure total in deposition process is 1.0 × 10 ^-2pa ~ 1.2 × 10 ^-2pa;

(3) experiment control N ₂be 1:1 with the flow-rate ratio of Ar, obtain the LiSiPON film that thickness is 80nm ~ 150nm, form staggered interconnection structure; The Main Morphology of film is amorphous state, has more space and be convenient to lithium ion transport and conduction in the skeleton of noncrystal membrane; Described ion beam bombardment Li ₃pO ₄and Si ₃n ₄refer to Li ₃pO ₄and Si ₃n ₄composite target.

2. the preparation method of LiSiPON lithium ion battery solid electrolyte film described in claim 1, (100) monocrystalline silicon piece of single-sided polishing wherein, first cleans 15 minutes with acetone, EtOH Sonicate successively, sends into immediately in vacuum deposition chamber after drying up; Before deposit film, first use 500eV, the Ar of 5mA ⁺cleaning 5 min ~ 10min is carried out to sample, during deposit film, regulates nitrogen argon than the sputtering time also accurately controlling each sample, plasma sputter source technological parameter: sputtering energy 0.9keV ~ 1.1keV, sputtering line 15mA ~ 20mA.

3. the application of LiSiPON lithium ion battery solid electrolyte film described in claim 1 in the miniature solid lithium battery material of preparation.