Series of compounds selenium-phosphorus-chromium-lithium and selenium-phosphorus-vanadium-lithium, selenium-phosphorus-chromium-lithium and selenium-phosphorus-vanadium-lithium two-dimensional crystal, preparation method and application

Abstract

The invention relates to a series of compounds selenium phosphorus chromium lithium, selenium phosphorus vanadium lithium, selenium phosphorus chromium lithium and selenium phosphorus vanadium lithium two-dimensional crystals, and a preparation method and application thereof, the molecular general formula of the compounds is LiBP2Se6, in the formula, B is a transition element Cr or V, the chemical formula of selenium phosphorus chromium lithium is LiCrP2Se6, and the molecular weight is 594.71; the chemical formula of the selenium phosphorus vanadium lithium is LiVP2Se6, and the molecular weight is 593.65; the crystal is crystallized in a centrosymmetric space group and belongs to a monoclinic system, the space group is C2 / c, and LiCrP2Se6 cell parameters are as follows: a = 6.239 (12), b = 10.803 (2), c = 13.504 (2), alpha = gamma = 90 degrees, beta = 99.34 degrees and Z = 4; the cell parameters of LiVP2Se6 are as follows: a = 6.241 (12), b = 10.806 (10), c = 13.514 (11), alpha = gamma = 90 degrees, beta = 99.32 degrees, and Z = 4. The material is prepared by a high-temperature melt spontaneous crystallization method, a chemical vapor transport method or a fluxing agent method. The material has a good thermal neutron capture cross section, a proper band gap, a good electron energy band structure and effective charge transfer.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of two-dimensional scattered neutron source crystal materials at room temperature, and particularly relates to a series of compounds lithium selenium phospho-chromium, lithium selenium phospho-vanadium, two-dimensional crystals of lithium selenium phospho-chromium and lithium selenium phospho-vanadium, and preparation methods and applications thereof. Background Art

[0002] Neutron detectors utilize the property that certain nuclides decay into high-energy charged fragments after capturing neutrons, and provide signals that are easy to detect through ionization products. In practice, only 3 He, 10 B, and 6 Li combine high neutron capture cross-sections with detectable decay products, and these isotopes have been incorporated into various detector architectures. The detector of choice for decades has been 3 He gas-filled sensors. However, in the past two decades, the storage of 3 He has been greatly depleted, and there is no viable way to increase production to meet demand. Therefore, many alternative technologies have been attracted, including those containing 6 Li and 10 B, which are emerging technologies promising efficient detectors because the concentration of neutron-absorbing isotopes in solids is much higher. There are two types of neutron detectors: indirect conversion detectors and direct conversion detectors. The detection efficiency of indirectly converted thermal neutrons can reach up to about 40%. Direct conversion uses a single material for neutron capture and charge collection, making the detector geometry simpler, and the intrinsic thermal neutron detection efficiency is close to 100%. However, it must be extremely pure and have low carrier capture because the neutron flux can be very low and the number of excited state charges generated is very small. Materials used for direct conversion include LiInSe 2 and hexagonal boron nitride, both of which have serious defects that limit their performance and cannot fully meet the current requirements for the update and development of scattered neutron source materials. There is an urgent need to develop crystal materials with excellent neutron detection capabilities. Summary of the Invention

[0003] The object of the present invention is to provide compounds lithium selenium phospho-chromium and lithium selenium phospho-vanadium with the chemical formula LiBP 2 Se 6 (B = Cr / V).

[0004] Another object of the present invention is to provide two-dimensional crystals of lithium selenium phospho-chromium and lithium selenium phospho-vanadium with the formula LiBP 2 Se 6 (B = Cr / V).

[0005] Another object of the present invention is to provide LiBP 2 Se 6(B = Cr / V) Preparation method of lithium chromium selenium phosphide and lithium vanadium selenium phosphide crystals.

[0006] Another object of the present invention is to provide LiBP 2 Se 6 (B = Cr / V) Applications of lithium chromium selenium phosphide and lithium vanadium selenium phosphide crystals.

[0007] A series of compounds, lithium chromium selenium phosphide and lithium vanadium selenium phosphide, described in the present invention, the general molecular formula of the compound is LiBP 2 Se 6 , where B in the formula is a transition element Cr or V, the compound belongs to the monoclinic system, and crystallizes in the centrosymmetric space group: C2 / c. The chemical formula of lithium chromium selenium phosphide is LiCrP 2 Se 6 , with a molecular weight of 594.71, being a lithium chromium selenium phosphide crystal and a pure powder sample; the chemical formula of lithium vanadium selenium phosphide is LiVP 2 Se 6 , with a molecular weight of 593.65, being a lithium vanadium selenium phosphide crystal and a pure powder sample.

[0008] The preparation method of the series of compounds lithium chromium selenium phosphide and lithium vanadium selenium phosphide is carried out according to the following steps:

[0009] According to the general molecular formula LiBP 2 Se 6 , where B in the formula is a transition element Cr or V, mix Li∶B∶P∶Se in a molar ratio of 1∶1∶2∶6 evenly, grind, load into a quartz tube, evacuate to 10 -3 Pa and carry out melting and encapsulation, put it into a muffle furnace, heat it at a rate of 5 - 50 °C / h to 820 - 920 °C, keep it at a constant temperature for 48 - 96 h, cool it to 260 °C at a rate of 10 - 50 °C / h, take out the sample after cooling, and flaky LiCrP will be obtained on the tube wall 2 Se 6 and LiVP 2 Se 6 crystals or powder-like LiCrP can be obtained by crushing and grinding 2 Se 6 or LiVP 2 Se 6 compounds, where the Li source material is Li, LiCl, LiI or Li 2 Se; the Cr source material is Cr, CrCl 3 or CrI 3 ; the V source material is V, VCl 3 or VI 3 ; the P source material is P or P 2 Se 5 , and elemental Se.

[0010] A series of two-dimensional lithium selenium phospho-chromium and lithium selenium phospho-vanadium crystals, the molecular general formula of the crystals being LiBP 2 Se 6 , where B in the formula is a transition element Cr or V; the LiCrP 2 Se 6 two-dimensional crystal crystallizes in a centrosymmetric space group, belongs to the monoclinic system, the space group is C2 / c, and the unit cell parameters are: α = γ = 90°, β = 99.34°, Z = 4; the LiVP 2 Se 6 two-dimensional crystal crystallizes in a centrosymmetric space group, belongs to the monoclinic system, the space group is C2 / c, and the unit cell parameters are: α = γ = 90°, β = 99.32°, Z = 4.

[0011] The preparation method of the series of two-dimensional lithium selenium phospho-chromium and lithium selenium phospho-vanadium crystals is to prepare the crystals by the high-temperature melt spontaneous crystallization method, the chemical vapor transport method or the flux method:

[0012] The growth of the two-dimensional lithium selenium phospho-chromium and lithium selenium phospho-vanadium crystals by the high-temperature melt spontaneous crystallization method is carried out according to the following specific steps:

[0013] a. According to the molecular general formula LiBP 2 Se 6 , where B in the formula is a transition element Cr or V, mix Li∶B∶P∶Se in a molar ratio of 1∶1∶2∶6 evenly, grind, load into a quartz tube, evacuate to 10 -3 Pa and carry out melting and encapsulation, put it into a muffle furnace, heat it up to 820 - 920 °C at a rate of 5 - 50 °C / h, keep it at a constant temperature for 48 - 96 h, cool it down to 260 °C at a rate of 10 - 50 °C / h, take out the sample after cooling, and flaky LiCrP will be obtained on the tube wall 2 Se 6 and LiVP 2 Se 6 crystals or crush and grind to obtain powdery LiCrP 2 Se 6 or LiVP 2 Se 6 compounds; the Li source materials are Li, LiCl, LiI or Li 2 Se; the Cr source materials are Cr, CrCl 3 or CrI 3 ; the V source materials are V, VCl 3 or VI 3 ; the P source materials are P or P 2 Se 5 , and elemental Se;

[0014] Or directly according to the molar ratio of Li∶B∶P∶S = 1∶1∶2∶6, mix the Li source material, Cr source material or V source material, P source material and elemental Se evenly, then load them into a quartz glass tube with Φ25mm×240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 820 - 920 °C, and keep it at a constant temperature for 24 - 96 h, where the Li source material is Li, LiCl, LiI or Li 2 Se; the Cr source material is Cr, CrCl 3 or CrI 3 ; the V source material is V, VCl 3 or VI 3 ; the P source material is P or P 2 Se 5 , and elemental Se;

[0015] b. Load the pure-phase lithium chromium phosphorus selenide and lithium vanadium phosphorus selenide powders obtained in step a into a quartz glass tube with Φ25mm×240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 820 - 920 °C, and keep it at a constant temperature for 24 - 96 h;

[0016] c. Slowly cool the product in step b to room temperature at a rate of 1 - 10 °C / h, turn off the muffle furnace, cut it open after the quartz tube cools down, and obtain light gray transparent LiCrP 2 Se 6 or gray transparent LiVP 2 Se 6 two-dimensional crystals;

[0017] The chemical vapor transport method for growing lithium chromium phosphorus selenide and lithium vanadium phosphorus selenide two-dimensional crystals is specifically operated according to the following steps:

[0018] a. According to the molecular general formula LiBP 2 Se 6 , where B is a transition element Cr or V, mix evenly according to the molar ratio of Li∶B∶P∶Se = 1∶1∶2∶6, grind, load into a quartz tube, evacuate to 10 -3 Pa and perform melting and sealing, put it into a muffle furnace, heat it to 820 - 920 °C at a rate of 5 - 50 °C / h, keep it at a constant temperature for 48 - 96 h, cool it to 260 °C at a rate of 10 - 50 °C / h, take out the sample after cooling, and plate-like LiCrP will be obtained on the tube wall 2 Se 6 and LiVP 2 Se 6 crystals or crush and grind to obtain powdered LiCrP 2 Se 6 or LiVP 2 Se6 Compound; the Li source material is Li, LiCl, LiI or Li 2 Se; the Cr source material is Cr, CrCl 3 or CrI 3 ; the V source material is V, VCl 3 or VI 3 ; the P source material is P or P 2 Se 5 , and elemental Se;

[0019] b. Perform chemical vapor transport at a high temperature zone of 900 - 920 °C and a low temperature zone of 750 - 770 °C, and grow LiCrP 2 Se 6 or LiVP 2 Se 6 crystals. The growth period is 10 - 40 days. After the growth is completed, slowly cool to room temperature at a rate of 1 - 10 °C / h, turn off the tube furnace. After the quartz tube cools, cut it open to obtain light gray transparent LiCrP 2 Se 6 or gray transparent LiVP 2 Se 6 ;

[0020] The growth of lithium chromium phosphoselenide and lithium vanadium phosphoselenide two-dimensional crystals by the flux method is specifically carried out according to the following steps:

[0021] a. According to the molecular general formula LiBP 2 Se 6 , where B is a transition element Cr or V, mix evenly in a molar ratio of Li∶B∶P∶Se = 1∶1∶2∶6, grind, load into a quartz tube, evacuate to 10 -3 Pa and perform melting and encapsulation. Put it into a muffle furnace, heat it to 820 - 920 °C at a rate of 5 - 50 °C / h, keep it at a constant temperature for 48 - 96 h, cool it to 260 °C at a rate of 10 - 50 °C / h. After cooling, take out the sample, and plate-like LiCrP 2 Se 6 and LiVP 2 Se 6 crystals will be obtained on the tube wall or powder-like LiCrP 2 Se 6 or LiVP 2 Se 6 compounds; the Li source material is Li, LiCl, LiI or Li 2 Se; the Cr source material is Cr, CrCl 3 or CrI 3 ; the V source material is V, VCl 3 or VI 3; The P source material is P or P 2 Se 5 , and elemental Se;

[0022] b. Mix the compound obtained in step a with a flux in a mass ratio of 1:0.5 - 5, load it into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen - oxygen flame, and then place it in a crystal growth furnace, slowly raise the temperature to 820 - 920°C, and keep it at a constant temperature for 6 - 16 days. The flux is LiCl, LiI, CrCl 3 , CrI 3 , VCl 3 or VI 3 ;

[0023] c. Then cool it to room temperature at a rate of 1 - 10°C / h to obtain a light - gray transparent LiCrP 2 Se 6 or a gray - transparent LiVP 2 Se 6 two - dimensional crystal.

[0024] Application of the series of lithium chromium phosphoselenide and lithium vanadium phosphoselenide two - dimensional crystals in the preparation of direct neutron detectors.

[0025] The lithium chromium phosphoselenide and lithium vanadium phosphoselenide two - dimensional crystals described above are used in neutron detectors. The prepared neutron detector mainly includes a LiBP 2 Se 6 (B = Cr / V) scattered neutron source device, which is used to detect the traces of the interaction between atomic and sub - atomic particles and the surrounding environment.

[0026] Use of the lithium chromium phosphoselenide and lithium vanadium phosphoselenide two - dimensional crystals described above in the preparation of new neutron - scattering source crystal materials, nuclear reactor detection devices, medical imaging devices, or environmental monitoring devices.

[0027] A compound of lithium chromium phosphoselenide and lithium vanadium phosphoselenide according to the present invention, wherein the LiCrP 2 Se 6 compound is prepared according to the following chemical reaction formula:

[0028] (1) Li + Cr + 2P + 6Se = LiCrP 2 Se 6 ;

[0029] (2) Li + Cr + P 2 Se 5 + Se = LiCrP 2 Se 6 ;

[0030] (3) Li 2Se + 2Cr + 2P 2 Se 5 + Se = 2LiCrP 2 Se 6 ;

[0031] (4) LiCl + CrCl 3 + 2P + 6Se = LiCrP 2 Se 6 + 2Cl 2 ↑;

[0032] (5) LiCl + CrCl 3 + P 2 Se 5 + Se = LiCrP 2 Se 6 + 2Cl 2 ↑;

[0033] (6) LiI + CrI 3 + 2P + 6Se = LiCrP 2 Se 6 + 2I 2 ↑;

[0034] (7) LiI + CrI 3 + P 2 Se 5 + Se = LiCrP 2 Se 6 + 2I 2 ↑;

[0035] The LiVP 2 Se 6 compound is prepared according to the following chemical reaction formula:

[0036] (1) Li + V + 2P + 6Se = LiVP 2 Se 6 ;

[0037] (2) Li + V + P 2 Se 5 + Se = LiVP 2 Se 6 ;

[0038] (3) Li 2 Se + 2V + 2P 2 Se 5 + Se = 2LiVP 2 Se 6 ;

[0039] (4) LiCl + VCl 3 + 2P + 6Se = LiVP2 Se 6 +2Cl 2 ↑;

[0040] (5)LiCl + VCl 3 +P 2 Se 5 +Se = LiVP 2 Se 6 +2Cl 2 ↑;

[0041] (6)LiI + VI 3 +2P + 6Se = LiVP 2 Se 6 +2I 2 ↑;

[0042] (7)LiI + VI 3 +P 2 Se 5 +Se = LiVP 2 Se 6 +2I 2 ↑。

[0043] The present invention provides LiBP 2 Se 6 (B = Cr / V) two-dimensional crystals, wherein the LiCrP 2 Se 6 two-dimensional crystals crystallize in a centrosymmetric space group, belonging to the monoclinic system, with the space group C2 / c, wherein LiCrP 2 Se 6 The unit cell parameters are: α = γ = 90°, β = 99.34°, Z = 4; wherein the LiVP 2 Se 6 two-dimensional crystals crystallize in a centrosymmetric space group, belonging to the monoclinic system, with the space group C2 / c, and the unit cell parameters are: α = γ = 90°, β = 99.32°, Z = 4. By the method of the present invention, centimeter-sized lithium chromium selenium phosphide and lithium vanadium selenium phosphide two-dimensional crystals can be obtained; by using a large-sized quartz tube and prolonging the growth period, relatively larger-sized lithium chromium selenium phosphide and lithium vanadium selenium phosphide two-dimensional crystals can be obtained, and the crystals are not easily broken and are easy to store.

[0044] For the compounds lithium chromium selenium phosphide and lithium vanadium selenium phosphide and the lithium chromium selenium phosphide and lithium vanadium selenium phosphide two-dimensional crystals and the preparation method and application thereof of the present invention, during the crystal growth process, the crystals are easy to grow and are transparent without inclusions, having the advantages of relatively fast growth rate, low cost, and easy access to relatively large-sized crystals; the obtained LiBP 2 Se6 (B = Cr / V) two-dimensional crystals and devices have the advantages of easy peeling, good mechanical properties, not easy to break and deliquesce, easy to process and preserve, etc.; the LiBP 2 Se 6 (B = Cr / V) two-dimensional crystals can be used to fabricate neutron detection devices. Description of the Drawings

[0045] Figure 1 This is a comparison chart of the X-ray diffraction pattern of the crystal c direction of the present invention with the theoretical value (taking LiCrP 2 Se 6 as an example).

[0046] Figure 2 This is a schematic structural diagram of the crystal of the present invention (taking LiCrP 2 Se 6 as an example);

[0047] Figure 3 This is the pulse height spectrum of alpha particles obtained by Gaussian fitting of the crystal of the present invention (taking LiCrP 2 Se 6 as an example). Detailed Description of the Invention

[0048] Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features. Unless specifically stated, each feature is only an example of a series of equivalent or similar features. The above is only for helping to understand the present invention and should not be regarded as a specific limitation of the present invention.

[0049] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0050] Example 1

[0051] According to the reaction formula Li + Cr + 2P + 6Se = LiCrP 2 Se 6 Prepare the compound LiCrP 2 Se 6 :

[0052] According to the reaction formula, the Cr source material is Cr; the P source material is P; the Li source is Li and elemental Se are mixed evenly, ground, loaded into a quartz tube, evacuated to 10 -3 Pa and then melt-sealed, placed in a muffle furnace, heated to 850 °C at a rate of 5 °C / h, kept at a constant temperature for 96 h, cooled to 260 °C at a rate of 5 °C / h, and after cooling, the sample is taken out and mashed and ground to obtain a powdery LiCrP 2 Se 6 compound.

[0053] Example 2

[0054] According to the reaction formula Li + Cr + P 2 Se 5 + Se = LiCrP 2 Se 6 To prepare the compound LiCrP 2 Se 6 :

[0055] According to the reaction formula, the Cr source material is Cr; the P source material is P 2 Se 5 ; The Li source is a mixture of Li and elemental Se, which is ground evenly, loaded into a quartz tube, evacuated to 10 -3 Pa and then melt-sealed, placed in a muffle furnace, heated to 850 °C at a rate of 25 °C / h, held at a constant temperature for 96 h, cooled to 260 °C at a rate of 8 °C / h, and after cooling, the sample is taken out, mashed and ground to obtain powdery LiCrP 2 Se 6 Compound.

[0056] Example 3

[0057] According to the reaction formula Li 2 Se + 2Cr + 2P 2 Se 5 + Se = 2LiCrP 2 Se 6 To prepare the compound LiCrP 2 Se 6 :

[0058] According to the reaction formula, the Cr source material is Cr; the P source material is P 2 Se 5 ; The Li source is Li 2 Se and elemental Se are mixed evenly, ground, loaded into a quartz tube, evacuated to 10 -3 Pa and then melt-sealed, placed in a muffle furnace, heated to 900 °C at a rate of 50 °C / h, held at a constant temperature for 96 h, cooled to 260 °C at a rate of 15 °C / h, and after cooling, the sample is taken out, mashed and ground to obtain powdery LiCrP 2 Se 6 Compound.

[0059] Example 4

[0060] According to the reaction formula LiCl + CrCl 3 + 2P + 6Se = LiCrP 2 Se 6 + 2Cl 2 ↑ To prepare the compound LiCrP 2 Se 6 :

[0061] Using the reaction formula, the Cr source material is CrCl 3 ; the P source material is P, and the Li source is a mixture of LiCl and elemental Se. After mixing evenly, it is ground, loaded into a quartz tube, evacuated to 10 -3 Pa and then hermetically sealed by melting. It is placed in a muffle furnace and heated to 820 °C at a rate of 40 °C / h, held at a constant temperature for 48 h, cooled to 260 °C at a rate of 20 °C / h. After cooling, the sample is taken out, crushed and ground to obtain powdery LiCrP 2 Se 6 compound.

[0062] Example 5

[0063] Using the reaction formula LiCl + CrCl 3 + P 2 Se 5 + Se = LiCrP 2 Se 6 + 2Cl 2 ↑ to prepare the compound LiCrP 2 Se 6 :

[0064] Using the reaction formula, the Cr source material is CrCl 3 ; the P source material is P 2 Se 5 , the Li source is a mixture of LiCl and elemental Se. After mixing evenly, it is ground, loaded into a quartz tube, evacuated to 10 -3 Pa and then hermetically sealed by melting. It is placed in a muffle furnace and heated to 820 °C at a rate of 30 °C / h, held at a constant temperature for 50 h, cooled to 260 °C at a rate of 30 °C / h. After cooling, the sample is taken out, crushed and ground to obtain powdery LiCrP 2 Se 6 compound.

[0065] Example 6

[0066] Using the reaction formula LiI + CrI 3 + 2P + 6Se = LiCrP 2 Se 6 + 2I 2 ↑ to prepare the compound LiCrP 2 Se 6 :

[0067] Using the reaction formula, the Cr source material is CrI 3 ; the P source material is P, and the Li source is a mixture of LiI and elemental Se. After mixing evenly, it is ground, loaded into a quartz tube, evacuated to 10 -3Pa is melted and encapsulated, then placed in a muffle furnace. It is heated to 830 °C at a rate of 20 °C / h, held at a constant temperature for 70 h, cooled to 260 °C at a rate of 15 °C / h. After cooling, the sample is taken out, crushed and ground to obtain powdered LiCrP 2 Se 6 compound.

[0068] Example 7

[0069] According to the reaction formula LiI + CrI 3 + P 2 Se 5 + Se = LiCrP 2 Se 6 + 2I 2 ↑ to prepare the compound LiCrP 2 Se 6 :

[0070] According to the reaction formula, the Cr source material is CrI 3 ; the P source material is P 2 Se 5 , the Li source is a mixture of LiI and elemental Se. After mixing evenly, it is ground, placed in a quartz tube, evacuated to 10 -3 Pa and then melted and encapsulated. It is placed in a muffle furnace, heated to 835 °C at a rate of 25 °C / h, held at a constant temperature for 72 h, cooled to 260 °C at a rate of 30 °C / h. After cooling, the sample is taken out, crushed and ground to obtain powdered LiCrP 2 Se 6 compound.

[0071] Example 8

[0072] According to the reaction formula Li + V + 2P + 6Se = LiVP 2 Se 6 to prepare the compound LiVP 2 Se 6 :

[0073] According to the reaction formula, the V source material is V; the P source material is P, and the Li source is a mixture of Li and elemental Se. After mixing evenly, it is ground, placed in a quartz tube, evacuated to 10 -3 Pa and then melted and encapsulated. It is placed in a muffle furnace, heated to 850 °C at a rate of 30 °C / h, held at a constant temperature for 80 h, cooled to 260 °C at a rate of 35 °C / h. After cooling, the sample is taken out, crushed and ground to obtain powdered LiVP 2 Se 6 compound.

[0074] Example 9

[0075] According to the reaction formula Li + V + P 2 Se 5 + Se = LiVP2 Se 6 Preparation of compound LiVP 2 Se 6 :

[0076] According to the reaction formula, the V source material is V; the P source material is P 2 Se 5 , the Li source is a mixture of Li and elemental Se, which is ground, loaded into a quartz tube, evacuated to 10 -3 Pa and then melt-sealed, placed in a muffle furnace, heated to 840 °C at a rate of 5 °C / h, held at a constant temperature for 96 h, cooled to 260 °C at a rate of 10 °C / h, the sample is taken out after cooling, and mashed and ground to obtain powdered LiVP 2 Se 6 Compound

[0077] Example 10

[0078] According to the reaction formula Li 2 Se + 2V + 2P 2 Se 5 + Se = 2LiVP 2 Se 6 Preparation of compound LiVP 2 Se 6 :

[0079] According to the reaction formula, the V source material is V; the P source material is P 2 Se 5 , the Li source is Li 2 Se and elemental Se are mixed evenly, ground, loaded into a quartz tube, evacuated to 10 -3 Pa and then melt-sealed, placed in a muffle furnace, heated to 850 °C at a rate of 15 °C / h, held at a constant temperature for 76 h, cooled to 260 °C at a rate of 18 °C / h, the sample is taken out after cooling, and mashed and ground to obtain powdered LiVP 2 Se 6 Compound

[0080] Example 11

[0081] According to the reaction formula LiCl + VCl 3 + 2P + 6Se = LiVP 2 Se 6 + 2Cl 2 ↑ Preparation of compound LiVP 2 Se 6 :

[0082] According to the reaction formula, the V source material is VCl 3 ; the P source material is P, the Li source is a mixture of LiCl and elemental Se, which is ground, loaded into a quartz tube, evacuated to 10 -3Pa and perform melt encapsulation, then place it in a muffle furnace, heat it to 820 °C at a rate of 30 °C / h, keep it at a constant temperature for 56 h, cool it to 260 °C at a rate of 20 °C / h, take out the sample after cooling, and crush and grind it to obtain powdered LiVP 2 Se 6 Compound.

[0083] Example 12

[0084] According to the reaction formula LiCl + VCl 3 + P 2 Se 5 + Se = LiVP 2 Se 6 + 2Cl 2 ↑ to prepare the compound LiVP 2 Se 6 :

[0085] According to the reaction formula, use VCl as the V source material 3 ; use P as the P source material 2 S 5 , mix LiCl and elemental Se as the Li source evenly, grind them, put them into a quartz tube, evacuate to 10 -3 Pa and perform melt encapsulation, then place it in a muffle furnace, heat it to 820 °C at a rate of 50 °C / h, keep it at a constant temperature for 96 h, cool it to 260 °C at a rate of 25 °C / h, take out the sample after cooling, and crush and grind it to obtain powdered LiVP 2 Se 6 Compound.

[0086] Example 13

[0087] According to the reaction formula LiI + VI 3 + 2P + 6Se = LiVP 2 Se 6 + 2I 2 ↑ to prepare the compound LiVP 2 Se 6 :

[0088] According to the reaction formula, use VI as the V source material 3 ; use P as the P source material, use LiI and elemental Se as the Li source, mix them evenly, grind them, put them into a quartz tube, evacuate to 10 -3 Pa and perform melt encapsulation, then place it in a muffle furnace, heat it to 830 °C at a rate of 35 °C / h, keep it at a constant temperature for 96 h, cool it to 260 °C at a rate of 50 °C / h, take out the sample after cooling, and crush and grind it to obtain powdered LiVP 2 Se 6 Compound.

[0089] Example 14

[0090] According to the reaction formula LiI + VI 3 + P 2 Se 5 + Se = LiVP 2 Se 6 + 2I 2 ↑ Preparation of the compound LiVP 2 Se 6 :

[0091] According to the reaction formula, the V source material is VI 3 ; the P source material is P 2 Se 5 , the Li source is a mixture of LiI and elemental Se. After mixing evenly, it is ground, loaded into a quartz tube, evacuated to 10 -3 Pa and then melt-sealed. It is placed in a muffle furnace and heated to 840°C at a rate of 45°C / h, kept at a constant temperature for 60 h, cooled to 260°C at a rate of 40°C / h. After cooling, the sample is taken out and mashed and ground to obtain powdered LiVP 2 Se 6 Compound.

[0092] Example 15

[0093] For growing lithium chromium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0094] The pure-phase lithium chromium phosphorus selenide powder obtained in Example 1 is loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, and slowly heated to a temperature of 820°C and kept at a constant temperature for 24 h;

[0095] Slowly cooled to room temperature at a rate of 1°C / h, turn off the muffle furnace. After the quartz tube cools, cut it open to obtain a light gray transparent LiCrP 2 Se 6 Two-dimensional crystal.

[0096] Example 16

[0097] For growing lithium chromium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0098] The pure-phase lithium chromium phosphorus selenide powder obtained in Example 2 is loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, and slowly heated to a temperature of 900°C and kept at a constant temperature for 36 h;

[0099] Slowly cooled to room temperature at a rate of 4°C / h, turn off the muffle furnace. After the quartz tube cools, cut it open to obtain a light gray transparent LiCrP with dimensions of 12 mm × 15 mm2 Se 6 Two-dimensional crystal

[0100] Example 17

[0101] The lithium chromium phosphorus selenium crystal is grown by the high-temperature melt spontaneous crystallization method, and the specific operation is carried out according to the following steps:

[0102] Put the pure-phase lithium chromium phosphorus selenium compound powder obtained in Example 3 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 850°C, and keep it at a constant temperature for 60h;

[0103] Slowly cool it to room temperature at a rate of 5°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a light gray transparent LiCrP with a size of 11mm×13mm 2 Se 6 Two-dimensional crystal

[0104] Example 18

[0105] The lithium chromium phosphorus selenium crystal is grown by the high-temperature melt spontaneous crystallization method, and the specific operation is carried out according to the following steps:

[0106] Put the pure-phase lithium chromium phosphorus selenium compound powder obtained in Example 4 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 920°C, and keep it at a constant temperature for 96h;

[0107] Slowly cool it to room temperature at a rate of 10°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a light gray transparent LiCrP with a size of 12mm×11mm 2 Se 6 Two-dimensional crystal

[0108] Example 19

[0109] The lithium chromium phosphorus selenium crystal is grown by the high-temperature melt spontaneous crystallization method, and the specific operation is carried out according to the following steps:

[0110] Put the pure-phase lithium chromium phosphorus selenium compound powder obtained in Example 5 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 910°C, and keep it at a constant temperature for 72h;

[0111] Slowly cool it to room temperature at a rate of 8°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a light gray transparent LiCrP with a size of 12mm×15mm 2 Se 6Two-dimensional crystal.

[0112] Example 20

[0113] The lithium chromium phosphorus selenide crystal is grown by the high-temperature melt spontaneous crystallization method, and the specific operation is carried out according to the following steps:

[0114] The pure-phase lithium chromium phosphorus selenide powder obtained in Example 6 was loaded into a quartz glass tube with a diameter of Φ25mm×240mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, slowly heated to a temperature of 840 °C, and kept at a constant temperature for 50 h;

[0115] Slowly cooled to room temperature at a rate of 6 °C / h, the muffle furnace was turned off, and after the quartz tube was cooled, it was cut open to obtain a light gray transparent LiCrP with a size of 12mm×12mm 2 Se 6 Two-dimensional crystal.

[0116] Example 21

[0117] The lithium chromium phosphorus selenide crystal is grown by the high-temperature melt spontaneous crystallization method, and the specific operation is carried out according to the following steps:

[0118] The pure-phase lithium chromium phosphorus selenide powder obtained in Example 7 was loaded into a quartz glass tube with a diameter of Φ25mm×240mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, slowly heated to a temperature of 880 °C, and kept at a constant temperature for 80 h;

[0119] Slowly cooled to room temperature at a rate of 10 °C / h, the muffle furnace was turned off, and after the quartz tube was cooled, it was cut open to obtain a light gray transparent LiCrP with a size of 12mm×16mm 2 Se 6 Two-dimensional crystal.

[0120] Example 22

[0121] The lithium vanadium phosphorus selenide crystal is grown by the high-temperature melt spontaneous crystallization method, and the specific operation is carried out according to the following steps:

[0122] The pure-phase lithium vanadium phosphorus selenide powder obtained in Example 8 was loaded into a quartz glass tube with a diameter of Φ25mm×240mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, slowly heated to a temperature of 820 °C, and kept at a constant temperature for 24 h;

[0123] Slowly cooled to room temperature at a rate of 1 °C / h, the muffle furnace was turned off, and after the quartz tube was cooled, it was cut open to obtain a gray transparent LiVP with a size of 11mm×15mm 2 Se 6 Crystal.

[0124] Grey transparent LiVP 2 Se 6 Two-dimensional crystal;

[0125] Example 23

[0126] The lithium vanadium phosphoselenide crystal is grown by the high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0127] Put the pure-phase lithium vanadium phosphoselenide powder obtained in Example 9 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 850°C, and keep it at a constant temperature for 36h;

[0128] Slowly cool it to room temperature at a rate of 2°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a grey transparent LiVP with dimensions of 12mm×13mm 2 Se 6 Two-dimensional crystal.

[0129] Example 24

[0130] The lithium vanadium phosphoselenide crystal is grown by the high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0131] Put the pure-phase lithium vanadium phosphoselenide powder obtained in Example 10 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 870°C, and keep it at a constant temperature for 48h;

[0132] Slowly cool it to room temperature at a rate of 4°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a grey transparent LiVP with dimensions of 12mm×15mm 2 Se 6 Two-dimensional crystal;

[0133] Example 25

[0134] The lithium vanadium phosphoselenide crystal is grown by the high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0135] Put the pure-phase lithium vanadium phosphoselenide powder obtained in Example 11 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 890°C, and keep it at a constant temperature for 60h;

[0136] Slowly cool it to room temperature at a rate of 6°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a grey transparent LiVP with dimensions of 11mm×13mm 2 Se6 Two-dimensional crystal

[0137] Example 26

[0138] The lithium vanadium phosphorus selenide crystal is grown by the spontaneous crystallization method of high-temperature melt. The specific operation is carried out according to the following steps:

[0139] Put the pure-phase lithium vanadium phosphorus selenide powder obtained in Example 12 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 900°C, and keep it at a constant temperature for 70h;

[0140] Slowly cool it to room temperature at a rate of 8°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a gray transparent LiVP with a size of 12mm×11mm 2 Se 6 Two-dimensional crystal

[0141] Example 27

[0142] The lithium vanadium phosphorus selenide crystal is grown by the spontaneous crystallization method of high-temperature melt. The specific operation is carried out according to the following steps:

[0143] Put the pure-phase lithium vanadium phosphorus selenide powder obtained in Example 13 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 910°C, and keep it at a constant temperature for 80h;

[0144] Slowly cool it to room temperature at a rate of 10°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a gray transparent LiVP with a size of 12mm×17mm 2 Se 6 Two-dimensional crystal

[0145] Example 28

[0146] The lithium vanadium phosphorus selenide crystal is grown by the spontaneous crystallization method of high-temperature melt. The specific operation is carried out according to the following steps:

[0147] Put the pure-phase lithium vanadium phosphorus selenide powder obtained in Example 14 into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 920°C, and keep it at a constant temperature for 96h;

[0148] Slowly cool it to room temperature at a rate of 10°C / h, turn off the muffle furnace, cut it open after the quartz tube cools, and obtain a gray transparent LiVP with a size of 12mm×18mm 2 Se 6 Two-dimensional crystal

[0149] Example 29

[0150] For growing lithium chromium phosphorus selenium crystals by the spontaneous crystallization method of high-temperature melt, the specific operation is carried out according to the following steps:

[0151] According to the reaction formula Li + Cr + 2P + 6Se = LiCrP 2 Se 6 Directly weigh 0.266 g of Li, 1.992 g of Cr, 2.373 g of P and 7.369 g of Se. After mixing evenly, put them into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 850 °C, and keep it at a constant temperature for 80 h;

[0152] Slowly cool to room temperature at a rate of 1.5 °C / h, turn off the muffle furnace, and cut the quartz tube after cooling to obtain a light gray transparent LiCrP with a size of 12mm×13mm 2 Se 6 crystal.

[0153] Example 30

[0154] For growing lithium chromium phosphorus selenium crystals by the spontaneous crystallization method of high-temperature melt, the specific operation is carried out according to the following steps:

[0155] According to the reaction formula Li + Cr + P 2 Se 5 + Se = LiCrP 2 Se 6 Directly weigh 0.152 g of Li, 1.139 g of Cr, 10.007 g of P 2 Se 5 and 0.702 g of Se. After mixing evenly, put them into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 840 °C, and keep it at a constant temperature for 90 h;

[0156] Slowly cool to room temperature at a rate of 2.5 °C / h, turn off the muffle furnace, and cut the quartz tube after cooling to obtain a light gray transparent LiCrP with a size of 12mm×15mm 2 Se 6 crystal.

[0157] Example 31

[0158] For growing lithium chromium phosphorus selenium crystals by the spontaneous crystallization method of high-temperature melt, the specific operation is carried out according to the following steps:

[0159] According to the reaction formula Li 2 Se + 2Cr + 2P 2 Se5 +Se = 2LiCrP 2 Se 6 Directly weigh 0.937 g of Li 2 Se, 1.049 g of Cr, 9.217 g of P 2 Se 5 and 0.797 g of Se, mix them evenly, then load them into a quartz glass tube with Φ25mm×240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 850 °C, and keep it at a constant temperature for 96 h;

[0160] Slowly cool to room temperature at a rate of 2.0 °C / h, turn off the muffle furnace, cut it after the quartz tube cools down, and obtain light gray transparent LiCrP with dimensions of 11mm×13mm 2 Se 6 crystals.

[0161] Example 32

[0162] The method for growing lithium chromium phosphorus selenide crystals by spontaneous crystallization of high-temperature melt is specifically operated according to the following steps:

[0163] According to the reaction formula LiCl + CrCl 3 + 2P + 6Se = LiCrP 2 Se 6 + 2Cl 2 ↑ Directly weigh 1.118 g of LiCl, 4.176 g of CrCl 3 , 1.634 g of P and 5.073 g of Se, mix them evenly, then load them into a quartz glass tube with Φ25mm×240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 800 °C, and keep it at a constant temperature for 96 h;

[0164] Slowly cool to room temperature at a rate of 2.0 °C / h, turn off the muffle furnace, cut it after the quartz tube cools down, and obtain light gray transparent LiCrP with dimensions of 12mm×11mm 2 Se 6 crystals.

[0165] Example 33

[0166] The method for growing lithium chromium phosphorus selenide crystals by spontaneous crystallization of high-temperature melt is specifically operated according to the following steps:

[0167] According to the reaction formula LiCl + CrCl 3 + P 2 Se 5 + Se = LiCrP 2 Se 6 + 2Cl 2↑ Weigh directly 0.738 g of LiCl, 2.756 g of CrCl 3 , 7.949 g of P 2 Se 5 and 0.558 g of Se. After mixing them evenly, put them into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 810 °C, and keep it at a constant temperature for 96 h;

[0168] Slowly cool it to room temperature at a rate of 3.0 °C / h, turn off the muffle furnace. After the quartz tube cools down, cut it open to obtain light gray transparent LiCrP with a size of 12 mm × 15 mm 2 Se 6 crystals.

[0169] Example 34

[0170] For growing lithium chromium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0171] a. According to the reaction formula LiI + CrI 3 + 2P + 6Se = LiCrP 2 Se 6 + 2I 2 ↑ Weigh directly 1.365 g of LiI, 4.413 g of CrI 3 , 0.632 g of P and 5.59 g of Se. After mixing them evenly, put them into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 810 °C, and keep it at a constant temperature for 96 h;

[0172] b. Slowly cool it to room temperature at a rate of 3.0 °C / h, turn off the muffle furnace. After the quartz tube cools down, cut it open to obtain light gray transparent LiCrP with a size of 12 mm × 12 mm 2 Se 6 crystals.

[0173] Example 35

[0174] For growing lithium chromium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0175] a. According to the reaction formula LiI + CrI 3 + P 2 Se 5 + Se = LiCrP 2 Se 6 + 2I 2 ↑ Weigh directly 1.457 g of LiI, 4.71 g of CrI 3 , 4.973 g of P2 Se 5 and 0.86 g of Se were uniformly mixed, placed into a quartz glass tube with a size of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, slowly heated to a temperature of 800 °C, and kept at a constant temperature for 90 h;

[0176] b. It was slowly cooled to room temperature at a rate of 2.0 °C / h, the muffle furnace was turned off, and after the quartz tube cooled, it was cut open to obtain a light gray transparent LiCrP 2 Se 6 crystal.

[0177] Example 36

[0178] For growing lithium vanadium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0179] a. According to the reaction formula Li + V + 2P + 6Se = LiVP 2 Se 6 Directly weigh 0.266 g of Li, 1.992 g of V, 2.373 g of P and 7.369 g of Se, place them into a quartz glass tube with a size of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, slowly heated to a temperature of 850 °C, and kept at a constant temperature for 90 h;

[0180] b. It was slowly cooled to room temperature at a rate of 2.0 °C / h, the muffle furnace was turned off, and after the quartz tube cooled, it was cut open to obtain a gray transparent LiVP 2 Se 6 crystal.

[0181] Example 37

[0182] For growing lithium vanadium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0183] a. According to the reaction formula Li + V + P 2 Se 5 + Se = LiVP 2 Se 6 Directly weigh 0.152 g of Li, 1.139 g of V, 10.007 g of P 2 Se 5 and 0.702 g of Se, uniformly mixed, placed into a quartz glass tube with a size of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a muffle furnace, slowly heated to a temperature of 840 °C, and kept at a constant temperature for 80 h;

[0184] b. Slowly cool to room temperature at a rate of 1.5 °C / h, turn off the muffle furnace, cut it after the quartz tube cools, and obtain gray transparent LiVP with a size of 12 mm × 13 mm 2 Se 6 crystals.

[0185] Example 38

[0186] For the growth of lithium vanadium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0187] a. According to the reaction formula Li 2 Se + 2V + 2P 2 Se 5 + Se = 2LiVP 2 Se 6 Directly weigh 0.975 grams of Li 2 Se, 1.092 grams of V, 9.596 grams of P 2 Se 5 and 0.337 grams of Se, mix them evenly, put them into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 850 °C, and keep it at a constant temperature for 90 h;

[0188] b. Slowly cool to room temperature at a rate of 2.5 °C / h, turn off the muffle furnace, cut it after the quartz tube cools, and obtain gray transparent LiVP with a size of 12 mm × 15 mm 2 Se 6 crystals.

[0189] Example 39

[0190] For the growth of lithium vanadium phosphorus selenide crystals by the high-temperature melt spontaneous crystallization method, the specific operation is carried out according to the following steps:

[0191] a. According to the reaction formula LiCl + VCl 3 + 2P + 6Se = LiVP 2 Se 6 + 2Cl 2 ↑ Directly weigh 1.118 grams of LiCl, 4.176 grams of VCl 3 、1.634 grams of P and 5.073 grams of Se, mix them evenly, put them into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 810 °C, and keep it at a constant temperature for 96 h;

[0192] b. Slowly cool to room temperature at a rate of 2.0 °C / h, turn off the muffle furnace, cut it after the quartz tube cools, and obtain gray transparent LiVP with a size of 11 mm × 13 mm2 Se 6 Crystal

[0193] Example 40

[0194] The lithium vanadium phosphorus selenide crystal is grown by the spontaneous crystallization method of high-temperature melt. The specific operation is carried out according to the following steps:

[0195] a. According to the reaction formula LiCl + VCl 3 + P 2 Se 5 + Se = LiVP 2 Se 6 + 2Cl 2 ↑ Directly weigh 0.738 g of LiCl, 2.756 g of VCl 3 、7.949 g of P 2 Se 5 and 0.558 g of Se. After mixing evenly, load them into a quartz glass tube with a diameter of Φ25mm × 240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 820 °C, and keep it at a constant temperature for 96 h;

[0196] b. Slowly cool it to room temperature at a rate of 2.0 °C / h, turn off the muffle furnace, cut it open after the quartz tube cools down, and obtain a gray transparent LiVP with a size of 12mm × 11mm 2 Se 6 Crystal

[0197] Example 41

[0198] The lithium vanadium phosphorus selenide crystal is grown by the spontaneous crystallization method of high-temperature melt. The specific operation is carried out according to the following steps:

[0199] a. According to the reaction formula LiI + VI 3 + 2P + 6Se = LiVP 2 Se 6 + 2I 2 ↑ Directly weigh 1.365 g of LiI, 4.413 g of VI 3 、0.632 g of P and 5.59 g of Se. After mixing evenly, load them into a quartz glass tube with a diameter of Φ25mm × 240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 800 °C, and keep it at a constant temperature for 96 h;

[0200] b. Slowly cool it to room temperature at a rate of 3.0 °C / h, turn off the muffle furnace, cut it open after the quartz tube cools down, and obtain a gray transparent LiVP with a size of 12mm × 17mm 2 Se 6 Crystal

[0201] Example 42

[0202] For the growth of lithium vanadium phosphorus selenide crystals by the spontaneous crystallization method of high-temperature melt, the specific operation is carried out according to the following steps:

[0203] a. According to the reaction formula LiI + VI 3 + P 2 Se 5 + Se = LiVP 2 Se 6 + 2I 2 ↑ Weigh directly 1.457 grams of LiI, 4.71 grams of VI 3 、4.973 grams of P 2 Se 5 and 0.86 grams of Se, after mixing evenly, load them into a quartz glass tube with Φ25mm×240mm, evacuate to 10 - 3 Pa, seal with a hydrogen-oxygen flame, place it in a muffle furnace, slowly raise the temperature to 810°C, and keep it at a constant temperature for 96 hours;

[0204] b. Slowly cool it to room temperature at a rate of 3.0°C / h, turn off the muffle furnace, cut it open after the quartz tube cools down, and obtain a gray transparent LiVP 2 Se 6 crystal with a size of 12mm×18mm.

[0205] Example 43

[0206] For the growth of lithium chromium phosphorus selenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0207] After grinding 25 grams of the compound lithium chromium phosphorus selenide obtained in Example 1 evenly, load it into a quartz glass tube with Φ25mm×240mm, evacuate to 10 -3 Pa, seal with a hydrogen-oxygen flame, place it in a tube furnace, and raise the temperature to 950°C at a rate of 20°C / h, and keep it at a constant temperature for 24 hours until the raw materials melt;

[0208] Perform chemical vapor transport with a high-temperature zone of 900°C and a low-temperature zone of 750°C, and grow LiCrP 2 Se 6 crystals through a horizontal gradient temperature field. The growth period is 10 days. After the growth is completed, slowly cool it to room temperature at a rate of 1°C / h, turn off the tube furnace, cut it open after the quartz tube cools down, and obtain a light gray transparent LiCrP 2 Se 6 crystal with a size of 14mm×20mm.

[0209] Example 44

[0210] For the growth of lithium chromium phosphorus selenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0211] After grinding 25 g of the compound lithium selenium phosphide chromium obtained in Example 2 evenly, it was loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tube furnace, heated to 950 °C at a rate of 20 °C / h, and kept at a constant temperature for 24 h until the raw materials melted;

[0212] Chemical vapor transport was carried out at a high temperature zone of 900 °C and a low temperature zone of 760 °C, and LiCrP 2 Se 6 crystal growth was carried out through a horizontal gradient temperature field. The growth period was 12 days. After the growth was completed, it was slowly cooled to room temperature at a rate of 1 °C / h. The tube furnace was turned off. After the quartz tube cooled, it was cut open to obtain a light gray transparent LiCrP 2 Se 6 crystal.

[0213] Example 45

[0214] For the growth of lithium selenium phosphide chromium crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0215] After grinding 25 g of the compound lithium selenium phosphide chromium obtained in Example 3 evenly, it was loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tube furnace, heated to 950 °C at a rate of 20 °C / h, and kept at a constant temperature for 24 h until the raw materials melted;

[0216] Chemical vapor transport was carried out at a high temperature zone of 900 °C and a low temperature zone of 770 °C, and LiCrP 2 Se 6 crystal growth was carried out through a horizontal gradient temperature field. The growth period was 15 days. After the growth was completed, it was slowly cooled to room temperature at a rate of 1 °C / h. The tube furnace was turned off. After the quartz tube cooled, it was cut open to obtain a light gray transparent LiCrP 2 Se 6 crystal.

[0217] Example 46

[0218] For the growth of lithium selenium phosphide chromium crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0219] After grinding 25 g of the compound lithium selenium phosphide chromium obtained in Example 4 evenly, it was loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tube furnace, heated to 950 °C at a rate of 20 °C / h, and kept at a constant temperature for 24 h until the raw materials melted;

[0220] Perform chemical vapor transport at a high temperature zone of 910 °C and a low temperature zone of 750 °C, and grow LiCrP 2 Se 6 crystals. The growth cycle is 10 days. After the growth is completed, slowly cool it to room temperature at a rate of 1 °C / h, turn off the tube furnace, and cut it after the quartz tube cools to obtain light gray transparent LiCrP 2 Se 6 crystals.

[0221] Example 47

[0222] For growing lithium chromium phosphoselenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0223] After grinding 25 grams of the lithium chromium phosphoselenide compound obtained in Example 5 evenly, load it into a quartz glass tube with a diameter of Φ25mm × 240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a tube furnace, and raise the temperature to 950 °C at a rate of 20 °C / h, and keep it at a constant temperature for 24 h until the raw materials melt;

[0224] Perform chemical vapor transport at a high temperature zone of 910 °C and a low temperature zone of 760 °C, and grow LiCrP 2 Se 6 crystals. The growth cycle is 15 days. After the growth is completed, slowly cool it to room temperature at a rate of 1 °C / h, turn off the tube furnace, and cut it after the quartz tube cools to obtain light gray transparent LiCrP 2 Se 6 crystals.

[0225] Example 48

[0226] For growing lithium chromium phosphoselenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0227] After grinding 25 grams of the lithium chromium phosphoselenide compound obtained in Example 6 evenly, load it into a quartz glass tube with a diameter of Φ25mm × 240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame, place it in a tube furnace, and raise the temperature to 950 °C at a rate of 20 °C / h, and keep it at a constant temperature for 24 h until the raw materials melt;

[0228] Perform chemical vapor transport at a high temperature zone of 910 °C and a low temperature zone of 770 °C, and grow LiCrP 2 Se 6Crystal growth was carried out with a growth period of 10 days. After the growth was completed, it was slowly cooled to room temperature at a rate of 1 °C / h. The tubular growth furnace was turned off. After the quartz tube cooled down, it was cut open to obtain a light gray transparent LiCrP with dimensions of 10 mm × 20 mm 2 Se 6 crystal.

[0229] Example 49

[0230] For the growth of lithium chromium phosphorus selenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0231] After grinding 25 grams of the compound lithium chromium phosphorus selenide obtained in Example 7 evenly, it was loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm. The vacuum was pumped to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tubular growth furnace, and heated to 950 °C at a rate of 20 °C / h. It was kept at a constant temperature for 24 h until the raw materials melted;

[0232] Chemical vapor transport was carried out with a high-temperature zone of 920 °C and a low-temperature zone of 760 °C. LiCrP 2 Se 6 crystal growth was carried out through a horizontal gradient temperature field. The growth period was 20 days. After the growth was completed, it was slowly cooled to room temperature at a rate of 1 °C / h. The tubular growth furnace was turned off. After the quartz tube cooled down, it was cut open to obtain a light gray transparent LiCrP with dimensions of 20 mm × 20 mm 2 Se 6 crystal.

[0233] Example 50

[0234] For the growth of lithium vanadium phosphorus selenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0235] After grinding 30 grams of the compound lithium vanadium phosphorus selenide obtained in Example 8 evenly, it was loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm. The vacuum was pumped to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tubular growth furnace, and heated to 920 °C at a rate of 20 °C / h. It was kept at a constant temperature for 36 h until the raw materials melted;

[0236] Chemical vapor transport was carried out with a high-temperature zone of 900 °C and a low-temperature zone of 750 °C. LiVP 2 Se 6 crystal growth was carried out through a horizontal gradient temperature field. The growth period was 25 days. After the growth was completed, it was slowly cooled to room temperature at a rate of 3 °C / h. The tubular growth furnace was turned off. After the quartz tube cooled down, it was cut open to obtain a gray transparent LiVP with dimensions of 20 mm × 20 mm 2 Se 6 crystal.

[0237] Example 51

[0238] For growing lithium vanadium phosphorus selenide crystals by chemical vapor transport method, the specific operation is carried out according to the following steps:

[0239] After grinding 30 g of the compound lithium vanadium phosphorus selenide obtained in Example 9 evenly, it is loaded into a quartz glass tube with a diameter of Φ25 mm and a length of 240 mm, and evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tube-type growth furnace, heated to 920 °C at a rate of 20 °C / h, and kept at a constant temperature for 36 h until the raw materials melt;

[0240] b. Carry out chemical vapor transport with a high-temperature zone of 900 °C and a low-temperature zone of 760 °C, and grow LiVP 2 Se 6 crystals. The growth period is 25 days. After the growth is completed, it is slowly cooled to room temperature at a rate of 3 °C / h, the tube-type growth furnace is turned off, and after the quartz tube cools, it is cut open to obtain a gray transparent LiVP 2 Se 6 crystal.

[0241] Example 52

[0242] For growing lithium vanadium phosphorus selenide crystals by chemical vapor transport method, the specific operation is carried out according to the following steps:

[0243] After grinding 30 g of the compound lithium vanadium phosphorus selenide obtained in Example 10 evenly, it is loaded into a quartz glass tube with a diameter of Φ25 mm and a length of 240 mm, and evacuated to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tube-type growth furnace, heated to 920 °C at a rate of 20 °C / h, and kept at a constant temperature for 36 h until the raw materials melt;

[0244] Carry out chemical vapor transport with a high-temperature zone of 900 °C and a low-temperature zone of 770 °C, and grow LiVP 2 Se 6 crystals. The growth period is 25 days. After the growth is completed, it is slowly cooled to room temperature at a rate of 2 °C / h, the tube-type growth furnace is turned off, and after the quartz tube cools, it is cut open to obtain a gray transparent LiVP 2 Se 6 crystal.

[0245] Example 53

[0246] For growing lithium vanadium phosphorus selenide crystals by chemical vapor transport method, the specific operation is carried out according to the following steps:

[0247] After grinding 30 g of the compound lithium vanadium phosphorus selenide obtained in Example 11 evenly, it is loaded into a quartz glass tube with a diameter of Φ25 mm and a length of 240 mm, and evacuated to 10 -3Pa, encapsulated with a hydrogen-oxygen flame, placed in a tube furnace, heated to 920 °C at a rate of 20 °C / h, and held at a constant temperature for 36 h until the raw materials melted;

[0248] Perform chemical vapor transport at a high temperature zone of 910 °C and a low temperature zone of 750 °C, and grow LiVP 2 Se 6 crystals. The growth cycle is 25 days. After the growth is completed, slowly cool to room temperature at a rate of 4 °C / h, turn off the tube furnace, and cut it after the quartz tube cools to obtain a gray transparent LiVP 2 Se 6 crystal.

[0249] Example 54

[0250] For the growth of lithium vanadium phosphorus selenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0251] After grinding 30 g of the lithium vanadium phosphorus selenide compound obtained in Example 12 evenly, load it into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuate to 10 -3 Pa, encapsulated with a hydrogen-oxygen flame, placed in a tube furnace, heated to 920 °C at a rate of 20 °C / h, and held at a constant temperature for 36 h until the raw materials melted;

[0252] Perform chemical vapor transport at a high temperature zone of 910 °C and a low temperature zone of 760 °C, and grow LiVP 2 Se 6 crystals. The growth cycle is 25 days. After the growth is completed, slowly cool to room temperature at a rate of 3 °C / h, turn off the tube furnace, and cut it after the quartz tube cools to obtain a gray transparent LiVP 2 Se 6 crystal.

[0253] Example 55

[0254] For the growth of lithium vanadium phosphorus selenide crystals by the chemical vapor transport method, the specific operation is carried out according to the following steps:

[0255] After grinding 30 g of the lithium vanadium phosphorus selenide compound obtained in Example 13 evenly, load it into a quartz glass tube with a diameter of Φ25 mm × 240 mm, evacuate to 10 -3 Pa, encapsulated with a hydrogen-oxygen flame, placed in a tube furnace, heated to 920 °C at a rate of 20 °C / h, and held at a constant temperature for 36 h until the raw materials melted;

[0256] Perform chemical vapor transport at a high temperature zone of 910 °C and a low temperature zone of 770 °C, and grow LiVP 2 Se 6Crystal growth was carried out with a growth period of 20 days. After the growth was completed, it was slowly cooled to room temperature at a rate of 3 °C / h. The tubular growth furnace was turned off. After the quartz tube cooled down, it was cut open to obtain a gray transparent LiVP 2 Se 6 crystal.

[0257] Example 56

[0258] For the growth of lithium vanadium phosphorus selenide crystals by chemical vapor transport method, the specific operation is carried out according to the following steps:

[0259] After grinding 30 g of the lithium vanadium phosphorus selenide compound obtained in Example 14 evenly, it was loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm, and the vacuum was pumped to 10 -3 Pa, sealed with a hydrogen-oxygen flame, placed in a tubular growth furnace, and heated to 920 °C at a rate of 20 °C / h. After keeping the temperature constant for 36 h until the raw materials melted;

[0260] Chemical vapor transport was carried out with a high temperature zone of 920 °C and a low temperature zone of 760 °C. LiVP 2 Se 6 crystal growth was carried out with a growth period of 30 days. After the growth was completed, it was slowly cooled to room temperature at a rate of 3 °C / h. The tubular growth furnace was turned off. After the quartz tube cooled down, it was cut open to obtain a gray transparent LiVP 2 Se 6 crystal.

[0261] Example 57

[0262] For the growth of lithium chromium phosphorus selenide crystals by the flux method, the specific operation is carried out according to the following steps:

[0263] The lithium chromium phosphorus selenide compound obtained in Example 4 was mixed with the flux CrCl 3 in a mass ratio of 1:0.5 (12 g of pure phase, 12 g of CrCl 3 ) and ground evenly. It was loaded into a quartz glass tube with a diameter of Φ25 mm × 240 mm, and the vacuum was pumped to 10 -3 Pa, then sealed with a hydrogen-oxygen flame and placed in a crystal growth furnace, and slowly heated to 850 °C and kept the temperature constant for 6 days;

[0264] Then it was cooled to room temperature at a cooling rate of 3 °C / h to obtain a light gray transparent LiCrP 2 Se 6 crystal.

[0265] Example 58

[0266] For the growth of lithium chromium phosphorus selenide crystals by the flux method, the specific operation is carried out according to the following steps:

[0267] The compound obtained in Example 1 was mixed with the flux lithium chloride selenophosphate chromium (LiCl) at a mass ratio of 1:0.5, and was loaded into a quartz glass tube with a size of Φ25mm×240mm. After evacuating to 10 -3 Pa, it was sealed with a hydrogen-oxygen flame and then placed in a crystal growth furnace, slowly heated to 820 °C, and kept at a constant temperature for 6 days;

[0268] Then it was cooled to room temperature at a cooling rate of 1 °C / h to obtain a light gray transparent LiCrP with a size of 12mm×10mm 2 Se 6 two-dimensional crystal.

[0269] Example 59

[0270] For the growth of lithium chromium selenophosphate crystal by the flux method, the specific operation is carried out according to the following steps:

[0271] The compound lithium chromium selenophosphate obtained in Example 2 was mixed with the flux LiI at a mass ratio of 1:1, and was loaded into a quartz glass tube with a size of Φ25mm×240mm. After evacuating to 10 -3 Pa, it was sealed with a hydrogen-oxygen flame and then placed in a crystal growth furnace, slowly heated to 850 °C, and kept at a constant temperature for 10 days;

[0272] Then it was cooled to room temperature at a cooling rate of 3 °C / h to obtain a light gray transparent LiCrP with a size of 6mm×16mm 2 Se 6 two-dimensional crystal.

[0273] Example 60

[0274] For the growth of lithium chromium selenophosphate crystal by the flux method, the specific operation is carried out according to the following steps:

[0275] The compound lithium chromium selenophosphate obtained in Example 3 was mixed with the flux CrCl 3 at a mass ratio of 1:2, and was loaded into a quartz glass tube with a size of Φ25mm×240mm. After evacuating to 10 -3 Pa, it was sealed with a hydrogen-oxygen flame and then placed in a crystal growth furnace, slowly heated to 870 °C, and kept at a constant temperature for 11 days;

[0276] Then it was cooled to room temperature at a cooling rate of 10 °C / h to obtain a light gray transparent LiCrP with a size of 12mm×15mm 2 Se 6 two-dimensional crystal.

[0277] Example 61

[0278] For the growth of lithium chromium selenophosphate crystal by the flux method, the specific operation is carried out according to the following steps:

[0279] The compound lithium selenium phospho-chromide obtained in Example 5 was mixed with the flux LiCl at a mass ratio of 1:5 (6 g of pure phase, 30 g of LiCl), placed in a quartz glass tube with a diameter of Φ25mm×240mm, evacuated to 10 -3 Pa, then sealed with a hydrogen-oxygen flame and placed in a crystal growth furnace, slowly heated to 850 °C, and kept at a constant temperature for 16 days;

[0280] Then it was cooled to room temperature at a cooling rate of 9 °C / h to obtain a light gray transparent LiCrP 2 Se 6 crystal.

[0281] Example 62

[0282] For the growth of lithium selenium phospho-chromide crystals by the flux method, the specific operation is carried out according to the following steps:

[0283] The compound lithium selenium phospho-chromide obtained in Example 6 was mixed with the flux CrI 2 at a mass ratio of 1:1 (12 g of pure phase, 12 g of CrI 2 ), ground evenly, placed in a quartz glass tube with a diameter of Φ25mm×240mm, evacuated to 10 -3 Pa, then sealed with a hydrogen-oxygen flame and placed in a crystal growth furnace, slowly heated to 800 °C, and kept at a constant temperature for 10 days;

[0284] Then it was cooled to room temperature at a cooling rate of 5 °C / h to obtain a light gray transparent LiCrP 2 Se 6 crystal.

[0285] Example 63

[0286] For the growth of lithium selenium phospho-chromide crystals by the flux method, the specific operation is carried out according to the following steps:

[0287] The compound lithium selenium phospho-chromide obtained in Example 7 was mixed with the flux LiI at a mass ratio of 1:0.8 (15 g of pure phase, 12 g of LiI), placed in a quartz glass tube with a diameter of Φ25mm×240mm, evacuated to 10 -3 Pa, then sealed with a hydrogen-oxygen flame and placed in a crystal growth furnace, slowly heated to 800 °C, and kept at a constant temperature for 6 days;

[0288] Then it was cooled to room temperature at a cooling rate of 2 °C / h to obtain a light gray transparent LiCrP 2 Se 6 crystal.

[0289] Example 64

[0290] For the growth of lithium selenium phospho-vanadate crystals by the flux method, the specific operation is carried out according to the following steps:

[0291] Mix the lithium selenium phosphovanadate obtained in Example 8 with the flux LiCl at a mass ratio of 1:0.5, load it into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame and then place it in a crystal growth furnace, slowly raise the temperature to 820 °C, and keep the temperature constant for 6 days;

[0292] c. Then cool it to room temperature at a cooling rate of 1 °C / h to obtain a gray transparent LiVP 2 Se 6 two-dimensional crystal.

[0293] Example 65

[0294] For the growth of lithium selenium phosphovanadate crystals by the flux method, the specific operation is carried out according to the following steps:

[0295] Mix the lithium selenium phosphovanadate obtained in Example 9 with the flux LiI at a mass ratio of 1:2, load it into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame and then place it in a crystal growth furnace, slowly raise the temperature to 850 °C, and keep the temperature constant for 10 days;

[0296] Then cool it to room temperature at a cooling rate of 5 °C / h to obtain a gray transparent LiVP 2 Se 6 two-dimensional crystal.

[0297] Example 66

[0298] For the growth of lithium selenium phosphovanadate crystals by the flux method, the specific operation is carried out according to the following steps:

[0299] Mix the lithium selenium phosphovanadate obtained in Example 10 with the flux VI 3 at a mass ratio of 1:3, load it into a quartz glass tube with a diameter of Φ25mm×240mm, evacuate to 10 -3 Pa, seal it with a hydrogen-oxygen flame and then place it in a crystal growth furnace, slowly raise the temperature to 880 °C, and keep the temperature constant for 11 days;

[0300] Then cool it to room temperature at a cooling rate of 10 °C / h to obtain a gray transparent LiVP 2 Se 6 two-dimensional crystal.

[0301] Example 67

[0302] For the growth of lithium selenium phosphovanadate crystals by the flux method, the specific operation is carried out according to the following steps:

[0303] The compound obtained in Example 11 was mixed with the flux VCl 3 in a mass ratio of 1:3 (10 g of the pure phase and 30 g of VCl 3 ). The mixture was loaded into a quartz glass tube with a diameter of Φ25 mm and a length of 240 mm. After evacuating to 10 -3 Pa, it was sealed with a hydrogen-oxygen flame and then placed in a crystal growth furnace. It was slowly heated to 840 °C and kept at a constant temperature for 11 days;

[0304] Then, it was cooled to room temperature at a rate of 6 °C / h to obtain a gray transparent LiVP 2 Se 6 crystal with dimensions of 12 mm × 14 mm.

[0305] Example 68

[0306] For the growth of lithium vanadium phosphorus selenide crystals by the flux method, the specific operation is carried out according to the following steps:

[0307] The compound lithium vanadium phosphorus selenide obtained in Example 12 was mixed with the flux VI 3 in a mass ratio of 1:5. The mixture was loaded into a quartz glass tube with a diameter of Φ25 mm and a length of 240 mm. After evacuating to 10 -3 Pa, it was sealed with a hydrogen-oxygen flame and then placed in a crystal growth furnace. It was slowly heated to 900 °C and kept at a constant temperature for 14 days;

[0308] Then, it was cooled to room temperature at a rate of 7 °C / h to obtain a gray transparent LiVP 2 Se 6 two-dimensional crystal with dimensions of 7 mm × 15 mm.

[0309] Example 69

[0310] For the growth of lithium vanadium phosphorus selenide crystals by the flux method, the specific operation is carried out according to the following steps:

[0311] The compound lithium vanadium phosphorus selenide obtained in Example 14 was mixed with the flux VI 3 in a mass ratio of 1:1. The mixture was loaded into a quartz glass tube with a diameter of Φ25 mm and a length of 240 mm. After evacuating to 10 -3 Pa, it was sealed with a hydrogen-oxygen flame and then placed in a crystal growth furnace. It was slowly heated to 910 °C and kept at a constant temperature for 13 days;

[0312] Then, it was cooled to room temperature at a rate of 9 °C / h to obtain a gray transparent LiVP 2 Se 6 two-dimensional crystal with dimensions of 12 mm × 12 mm.

[0313] Example 70

[0314] For the growth of lithium vanadium phosphorus selenide crystals by the flux method, the specific operation is carried out according to the following steps:

[0315] The compound obtained in Example 13 was mixed with the flux VCl 3 in a mass ratio of 1:2 (10 g of the pure phase, 20 g of VI 3 ), and the mixture was loaded into a quartz glass tube with a diameter of Φ25 mm and a length of 240 mm. After evacuating to 10 -3 Pa, it was sealed with a hydrogen-oxygen flame and then placed in a crystal growth furnace. It was slowly heated to 840 °C and held at a constant temperature for 16 days;

[0316] Then, it was cooled to room temperature at a rate of 10 °C / h to obtain a gray transparent LiVP 2 Se 6 crystal with dimensions of 10 mm × 20 mm.

[0317] Example 71

[0318] The LiCrP 2 Se 6 crystal obtained in Example 15 was fabricated into a 7 mm × 7 mm LiCrP 2 Se 6 device. Using the α particles from a 241Am source as the indicator for the neutron capture reaction, the energy resolution of the compact two-dimensional LiCrP 2 Se 6 detector was determined to be 13%. Direct neutron detection was achieved using the LiCrP 2 Se 6 detector. Neutron detection tests were performed on the LiCrP 2 Se 6 crystal using a polyethylene moderator and a californium-252 source, and a clear response was observed, showing good neutron counting characteristics.

[0319] Example 72

[0320] The LiCrP 2 Se 6 crystal obtained in Example 43 was fabricated into a 10 mm × 10 mm LiCrP 2 Se 6 device. Using the α particles from a 241Am source as the indicator for the neutron capture reaction, the energy resolution of the compact two-dimensional LiCrP 2 Se 6 detector was determined to be 15%. Direct neutron detection was achieved using the LiCrP 2 Se 6 detector; Neutron detection tests were performed on the LiCrP 2 Se 6 crystal using a polyethylene moderator and a californium-252 source, and a clear response was observed, showing good neutron counting characteristics.

[0321] Example 73

[0322] The LiVP 2 Se 6 crystal obtained in Example 22 was fabricated into a 7 mm×7 mm LiVP 2 Se 6 device. Using the α-particles from a 241Am source as an indicator of the neutron capture reaction, the energy resolution of the compact two-dimensional LiVP 2 Se 6 detector was determined to be 12%. Direct neutron detection was achieved using the LiVP 2 Se 6 detector. Neutron detection tests were carried out on the LiVP 2 Se 6 crystal using a polyethylene moderator and a californium-252 source, and a clear response was observed, showing good neutron counting characteristics.

[0323] Example 74

[0324] The LiVP 2 Se 6 crystal obtained in Example 36 was fabricated into a 9 mm×9 mm LiVP 2 Se 6 device. Using the α-particles from a 241Am source as an indicator of the neutron capture reaction, the energy resolution of the compact two-dimensional LiVP 2 Se 6 detector was determined to be 13%. Direct neutron detection was achieved using the LiVP 2 Se 6 detector. Neutron detection tests were carried out on the LiVP 2 Se 6 crystal using a polyethylene moderator and a californium-252 source, and a clear response was observed, showing good neutron counting characteristics.

Claims

1. A series of compounds of lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium, characterized in that The molecular formula of the compound is LiBP2Se6, wherein B is a transition element Cr or V. The compound belongs to the monoclinic system and crystallizes in the centrosymmetric space group: C 2 / c The chemical formula of lithium selenium phosphorus chromium is LiCrP2Se6, the molecular weight is 594.71, and it is a pure sample of lithium selenium phosphorus chromium crystals and powder; the chemical formula of lithium selenium phosphorus vanadium is LiVP2Se6, the molecular weight is 593.65, and it is a pure sample of lithium selenium phosphorus vanadium crystals and powder.

2. The method for preparing the series of compounds of lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium according to claim 1, characterized in that Follow these steps: According to the molecular formula of LiBP2Se6, where B is the transition element Cr or V, the molar ratio of Li:B:P:Se=1:1:2:6 is mixed evenly, ground, put into a quartz tube, and evacuated to 10 -3 Pa and melt-package it, put it into a muffle furnace, heat it to 820-920 ℃ at a rate of 5-50 ℃ / h, keep it at a constant temperature for 48-96 h, and then reduce it to 260 ℃ at a rate of 10-50 ℃ / h. After cooling, take out the sample, and obtain flaky LiCrP2Se6 and LiVP2Se6 crystals on the tube wall or crush and grind to obtain powdered LiCrP2Se6 or LiVP2Se6 compounds, wherein the Li source material is Li, LiCl, LiI or Li2Se; the Cr source material is Cr, CrCl3 or CrI3; the V source material is V, VCl3 or VI3; the P source material is P or P2Se5, and elemental Se.

3. A series of lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium two-dimensional crystals, characterized in that The molecular formula of the crystal is LiBP2Se6, wherein B is a transition element Cr or V; the LiCrP2Se6 two-dimensional crystal is crystallized in a central symmetric space group, belongs to the monoclinic system, and has a space group of C 2 / c , the unit cell parameters are: a = 6.239(12) Å, b = 10.803(2) Å, c = 13.504(2) Å, α = γ = 90°, β = 99.34°, Z = 4; the LiVP2Se6 two-dimensional crystal is crystallized in a centrosymmetric space group, belongs to the monoclinic system, and the space group is C 2 / c , the unit cell parameters are: a = 6.241(12) Å, b = 10.806(10) Å, c = 13.514(11) Å, α = γ = 90°, β = 99.32°, Z = 4.

4. A method for preparing a series of lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium two-dimensional crystals as claimed in claim 3, characterized in that Crystals are prepared by spontaneous crystallization from high temperature melts, chemical vapor transport or flux methods: The high temperature melt spontaneous crystallization method grows lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium two-dimensional crystals, and the specific operation is carried out according to the following steps: a. Mix the molecular formula of LiBP2Se6, where B is the transition element Cr or V, and the molar ratio of Li:B:P:Se=1:1:2:6, grind, put into a quartz tube, and evacuate to 10 -3 Pa and melt packaging, put it into a muffle furnace, heat it to 820-920 ℃ at a rate of 5-50 ℃ / h, keep the temperature constant for 48-96 h, and then reduce it to 260 ℃ at a rate of 10-50 ℃ / h. Take out the sample after cooling, and obtain flaky LiCrP2Se6 and LiVP2Se6 crystals on the tube wall or crush and grind to obtain powdered LiCrP2Se6 or LiVP2Se6 compounds; the Li source material is Li, LiCl, LiI or Li2Se; the Cr source material is Cr, CrCl3 or CrI3; the V source material is V, VCl3 or VI3; the P source material is P or P2Se5, and elemental Se; Or directly mix the Li source material, Cr source material or V source material, P source material and single substance Se in a molar ratio of Li∶B∶P∶S=1∶1∶2∶6, put them into a Φ25 mm × 240 mm quartz glass tube, and evacuate to 10 -3 Pa is packaged with hydrogen-oxygen flame, placed in a muffle furnace, and slowly raised to a temperature of 820-920°C, and kept at a constant temperature for 24-96 h, wherein the Li source material is Li, LiCl, LiI or Li2Se; the Cr source material is Cr, CrCl3 or CrI3; the V source material is V, VCl3 or VI3; the P source material is P or P2Se5, and elemental Se; b. Put the pure phase of the compound selenium phosphorus chromium lithium and selenium phosphorus vanadium lithium powder obtained in step a into a Φ25 mm × 240 mm quartz glass tube and evacuate to 10 -3 Pa, encapsulated with hydrogen-oxygen flame, placed in a muffle furnace, slowly raised to 820-920 °C, and kept at this temperature for 24-96 h; c. Slowly cool the reaction mixture in step b to room temperature at a rate of 1-10 °C / h, turn off the muffle furnace, and cut the quartz tube after cooling to obtain a light gray transparent LiCrP2Se6 or gray transparent LiVP2Se6 two-dimensional crystal; The chemical vapor transport method for growing lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium two-dimensional crystals is specifically performed in the following steps: a. Mix the molecular formula of LiBP2Se6, where B is the transition element Cr or V, in a molar ratio of Li:B:P:Se=1:1:2:6, grind, put into a quartz tube, and evacuate to 10 -3 Pa and melt packaging, put it into a muffle furnace, heat it to 820-920 ℃ at a rate of 5-50 ℃ / h, keep the temperature constant for 48-96 h, and then reduce it to 260 ℃ at a rate of 10-50 ℃ / h. Take out the sample after cooling, and obtain flaky LiCrP2Se6 and LiVP2Se6 crystals on the tube wall or crush and grind to obtain powdered LiCrP2Se6 or LiVP2Se6 compounds; the Li source material is Li, LiCl, LiI or Li2Se; the Cr source material is Cr, CrCl3 or CrI3; the V source material is V, VCl3 or VI3; the P source material is P or P2Se5, and elemental Se; b. Chemical vapor transport is performed at 900-920°C in the high temperature zone and 750-770°C in the low temperature zone, and LiCrP2Se6 or LiVP2Se6 crystals are grown through a horizontal gradient temperature field. The growth cycle is 10-40 days. After the growth is completed, the temperature is slowly reduced to room temperature at a rate of 1-10°C / h, and the tubular growth furnace is closed. After the quartz tube is cooled, it is cut open to obtain light gray transparent LiCrP2Se6 or gray transparent LiVP2Se6; The flux method for growing lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium two-dimensional crystals is specifically performed in the following steps: a. Mix the molecular formula of LiBP2Se6, where B is the transition element Cr or V, and the molar ratio of Li:B:P:Se=1:1:2:6, grind, put into a quartz tube, and evacuate to 10 -3 Pa and melt packaging, put it into a muffle furnace, heat it to 820-920℃ at a rate of 5-50℃ / h, keep the temperature constant for 48-96 h, and then reduce it to 260℃ at a rate of 10-50℃ / h. After cooling, take out the sample, and obtain flaky LiCrP2Se6 and LiVP2Se6 crystals on the tube wall or crush and grind to obtain powdered LiCrP2Se6 or LiVP2Se6 compounds; the Li source material is Li, LiCl, LiI or Li2Se; the Cr source material is Cr, CrCl3 or CrI3; the V source material is V, VCl3 or VI3; the P source material is P or P2Se5, and elemental Se; b. The compound obtained in step a is mixed with a flux in a mass ratio of 1:0.5-5, placed in a quartz glass tube of Φ25 mm × 240 mm, and evacuated to 10 -3 After Pa, it is packaged with hydrogen-oxygen flame and placed in a crystal growth furnace, slowly raised to 820-920 ° C, and kept at a constant temperature for 6-16 days, wherein the flux is LiCl, LiI, CrCl3, CrI3, VCl3 or VI3; c. Then cool down to room temperature at a cooling rate of 1-10 ℃ / h to obtain light gray transparent LiCrP2Se6 or gray transparent LiVP2Se6 two-dimensional crystals.

5. Use of the series of lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium two-dimensional crystals as claimed in claim 3 in the preparation of direct neutron detectors.

6. Use of the lithium selenium phosphorus chromium and lithium selenium phosphorus vanadium two-dimensional crystal as described in claim 3 in the preparation of neutron scattering source crystal materials, nuclear reactor detection devices, medical imaging devices, or environmental monitoring devices.

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