A chromium oxide composite material added with an activator and a preparation method and application thereof

Abstract

The application discloses a chromium oxide composite material added with an activator, which is prepared from CrO3 and the activator through ball milling and high-temperature solid-phase reaction in sequence; and the activator is an electrochemical active material based on a metal oxide with a melting point higher than that of CrO3. The application can effectively improve the specific energy, specific capacity and high-rate discharge performance of the obtained composite material by adding the activator in the preparation process of the chromium oxide material, and can provide a new idea for the research and development of a high-performance battery system; and the preparation method is relatively simple and convenient to operate, and is suitable for popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of electrode materials and their preparation technology, specifically relating to a chromium oxide composite material with added activator and its preparation and application. Background Technology

[0002] Although lithium-ion batteries are becoming increasingly widely used, lithium primary batteries still hold significant research and application value due to their high energy density, high operating voltage, and long storage life. Currently used cathode materials for lithium primary batteries (such as manganese dioxide, thionyl chloride, carbon fluoride, and iron disulfide) each face insurmountable technical challenges. For example, Li / MnO2 batteries suffer from poor temperature adaptability, Li / SOCl2 batteries exhibit slow kinetics, and Li / CF2 batteries... X The battery's rate performance is poor; there is an urgent need to further develop lithium primary battery cathode materials with good overall performance.

[0003] Chromium oxide cathode materials are used in both lithium primary batteries and lithium-ion batteries, exhibiting high discharge capacity and a high discharge voltage plateau (3.0V, vs. Li). + Chromium oxide batteries offer advantages such as high conductivity (e.g., Cr3O8 / Cr2O5), but their application has long been limited to low-current discharge due to their low conductivity, restricting their range of applications. With in-depth research on chromium oxide materials, researchers have discovered that the preparation conditions play a crucial role in determining the type of chromium oxide obtained and its electrochemical performance. Under pure-phase conditions, the electrochemical performance is Cr3O8 > Cr2O5 > CrO2. Related studies also indicate that, theoretically, amorphous chromium oxide materials have a higher specific surface area and therefore may have higher specific energy. Currently, the preparation conditions of pure-phase chromium oxide materials, especially Cr3O8, are the most extensively studied. Patent CN108609656A discloses a method for synthesizing pure-phase Cr3O8 or Cr8O2. 21 This method, which does not require high pressure or a pure oxygen environment, can obtain pure phase Cr3O8 or Cr8O by controlling the temperature fluctuation range in air. 21 However, it is difficult to precisely control temperature fluctuations, often resulting in mixed-phase chromium oxide materials that are hard to achieve the desired effect.

[0004] In recent years, to improve the conductivity or specific capacity of chromium oxides, researchers have combined prepared chromium oxide materials with copper, carbon nanotubes, and other materials. For example, patent CN112201773A discloses a method for preparing copper-coated chromium oxide materials, which coats the surface of chromium oxide materials with copper to improve their conductivity, but this results in a decrease in the initial discharge specific capacity. Patent CN112968176A discloses a chromium oxide / CNTS composite material, which combines the prepared chromium oxide material with carbon nanotubes through high-energy ball milling, improving the material's conductivity, but without improving its high-rate discharge performance, only its low-current discharge performance. Therefore, further exploration of chromium oxide-based composite materials and their preparation processes that can effectively solve the problems of low discharge capacity and poor rate performance of chromium oxide materials is of significant research and application value. Summary of the Invention

[0005] The main objective of this invention is to address the problems and shortcomings of existing technologies by providing a chromium oxide composite material with added activator, which can effectively solve the problems of low discharge capacity and poor discharge rate performance of existing chromium oxide materials; moreover, the preparation method involved is relatively simple and easy to operate, and is suitable for widespread application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A chromium oxide composite material with added activator is obtained by sequentially ball milling and high-temperature solid-state reaction of CrO3 and activator as raw materials; the activator is a metal oxide-based electrochemically active material with a melting point higher than CrO3.

[0008] Preferably, the activator has a melting point greater than 400°C.

[0009] Furthermore, the activator may be selected from one or more of the following: LiMnO4 (spinel type), V2O5, LiCoO2, MnO2, PbO2, silver powder, copper powder, Co3O4, Co2O3, etc.

[0010] In the above scheme, the mass ratio of CrO3 to activator is 100:(1-30).

[0011] Preferably, the mass ratio of CrO3 to activator is 100:(5-10); more preferably, it is 100:10.

[0012] In the above scheme, the CrO3 is a flake-like material; the activator used is a solid powder.

[0013] In the above scheme, the ball milling rate is 200-350 r / min, and the time is 2-5 h.

[0014] Preferably, the ball milling process employs planetary ball milling.

[0015] In the above scheme, the high-temperature solid-phase reaction temperature is 200-400℃, the time is 6-48h, and the reaction atmosphere can be argon, nitrogen, air or oxygen atmosphere, etc.; preferably, it is an oxygen atmosphere.

[0016] In the above scheme, chromium oxide CrO3 is very sensitive to water. Therefore, the mixing of CrO3 with the activator and the ball milling jar packaging process should be carried out in an anhydrous drying room to prevent chromium oxide CrO3 from coming into contact with moisture and to avoid affecting the chromium oxide composite material.

[0017] The chromium oxide composite material with added activator obtained according to the above scheme has chromium oxide crystal phase Cr3O8; its electrochemical performance and processing performance are significantly improved.

[0018] The above-mentioned method for preparing a chromium oxide composite material with added activator specifically includes the following steps:

[0019] 1) After mixing chromium oxide CrO3 with the activator, transfer it into a planetary ball mill jar for ball milling. The mixing and transfer of materials should be carried out in an anhydrous drying room.

[0020] 2) Place the mixture obtained in step 1) in a tube furnace and calcine it at a temperature of 200-400℃ for 6-48 hours;

[0021] 3) Transfer the calcined product obtained in step 2) into a planetary ball mill jar for secondary ball milling. After pulverization, pass it through a 200-mesh sieve to obtain the chromium oxide composite material with added activator.

[0022] In the above scheme, the heating rate used in step 2) is 5-10℃ / min.

[0023] In the above scheme, the calcination atmosphere used in step 2) is air, argon, nitrogen or oxygen, etc.

[0024] Preferably, when using an oxygen atmosphere in step 2), the flow rate of oxygen is 10-100 mL / min.

[0025] Preferably, the calcination temperature in step 2) is 250–300°C; more preferably, it is 260–280°C.

[0026] In the above scheme, the primary ball milling uses a rotation speed of 200-350 r / min and a time of 2-5 h; the secondary ball milling uses a rotation speed of 300-400 r / min and a time of 2-5 h.

[0027] The chromium oxide composite material with added activator obtained according to the above scheme is used as the positive electrode active material of lithium primary battery. The specific application steps include: mixing the positive electrode active material, conductive carbon and binder in proportion to prepare a uniform slurry, and then setting it on the surface of a metal substrate to prepare a positive electrode sheet.

[0028] In the above scheme, the adhesive can be one or more of PVDF, PTFE, SBR, etc.; the metal substrate can be a conductive metal material such as aluminum foil, aluminum mesh or stainless steel foil.

[0029] In the above scheme, the mass ratio of the positive electrode active material, conductive carbon and binder is (7-8):(2-1):1.

[0030] The principle of this invention is as follows:

[0031] This invention involves ball milling CrO3 with an activator followed by calcination. During calcination, CrO3 undergoes melting, boiling, decomposition, and solidification to obtain chromium oxide materials. The introduced activator remains a solid powder throughout the calcination process. On one hand, it acts as a physical barrier, influencing the solidification and crystallization process of the chromium oxide materials. On the other hand, it provides crystallization sites for the chromium oxide materials and induces the growth of chromium oxide crystals, improving the crystal form of the chromium oxide in the resulting composite material (resulting in a composite material dominated by the Cr3O8 phase). This effectively improves its electrochemical properties, such as capacitance and discharge rate. Simultaneously, it reduces the hardness of the solidified chromium oxide materials, facilitating pulverization and processing.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1) This invention introduces an activator to participate in the solidification and crystallization process of chromium oxides, effectively controlling the crystal form of the obtained chromium oxide materials and significantly improving the rate discharge performance of the obtained chromium oxide-based materials;

[0034] 2) The introduced activator has good conductivity and is composited with chromium oxide using a high-temperature solid-state method. During the composite process, the activator is uniformly dispersed in the bulk phase of the chromium oxide material to form a conductive network, which can further and effectively improve the conductivity of the chromium oxide material.

[0035] 3) By introducing an activator during the preparation of chromium oxides, the hardness of the resulting chromium oxide-based composite material can be adjusted simultaneously, which facilitates crushing and processing as well as electrode preparation;

[0036] 4) Introducing an activator while preparing chromium oxide materials, and using a one-step high-temperature solid-state method to prepare chromium oxide composite materials and simultaneously optimize their performance, can greatly simplify the production process and is suitable for widespread application. Attached Figure Description

[0037] Figure 1The discharge curves of the five groups of batteries obtained from Application Example 1, Application Example 2, Application Example 3, Application Example 4 and Comparative Example 1 at a current density of 100 mA / g are shown respectively.

[0038] Figure 2 The discharge curves of four sets of batteries in Application Examples 2, 5, 6 and 7 at a current density of 100 mA / g are shown.

[0039] Figure 3 The rate discharge curve of the CR2032 coin cell obtained from Example 2 is shown.

[0040] Figure 4 The high-current discharge curve of the CR2032 coin cell obtained in Application Example 2 and Comparative Example 1 is shown.

[0041] Figure 5 The discharge curves of the CR2032 coin cells obtained in Example 8 and Comparative Example 2 at a current density of 100 mA / g are shown.

[0042] Figure 6 The discharge curves of CR2032 coin cells obtained in Comparative Example 1, Example 2 (Application Example 2), Example 9 (Application Example 9), and Example 10 (Application Example 10) at a current density of 100 mA / g are shown.

[0043] Figure 7 The XRD patterns of the chromium oxide composite materials obtained in Example 2 and Comparative Example 1 are shown. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] In the following examples, the chromium trioxide used has a purity of 99.99 wt% and is a flaky solid; the activator used is manganese dioxide powder, lead dioxide powder, or vanadium pentoxide powder; its purity is 99.99% and its particle size is 3-10 μm.

[0046] Example 1

[0047] A chromium oxide composite material with added activator is prepared by the following steps:

[0048] 1) Weigh 30g of chromium trioxide (CrO3) and 0.3g of manganese dioxide (the mass ratio of chromium trioxide to activator is 100:1), mix them, and put them into a ball mill jar. Ball mill for 3 hours at 300r / min. The steps of weighing the materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0049] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 270℃ at a heating rate of 5℃ / min, and hold it at 270℃ for 24 hours.

[0050] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0051] Example 2

[0052] A chromium oxide composite material with added activator is prepared by the following steps:

[0053] 1) Weigh 30g of chromium trioxide (CrO3) and 3g of manganese dioxide (the mass ratio of chromium trioxide to activator is 100:10), mix them, put them into a ball mill jar, and ball mill them for 3 hours at 300r / min; the steps of weighing materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0054] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 270℃ at a heating rate of 5℃ / min, and hold it at 270℃ for 24 hours.

[0055] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0056] Example 3

[0057] A chromium oxide composite material with added activator is prepared by the following steps:

[0058] 1) Weigh 30g of chromium trioxide (CrO3) and 4.5g of manganese dioxide (the mass ratio of chromium trioxide to activator is 100:15), mix them, put them into a ball mill jar, and ball mill them for 3 hours at 300r / min. The steps of weighing the materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0059] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 270℃ at a heating rate of 5℃ / min, and hold it at 270℃ for 24 hours.

[0060] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0061] Example 4

[0062] A chromium oxide composite material with added activator is prepared by the following steps:

[0063] 1) Weigh 30g of chromium trioxide (CrO3) and 9g of manganese dioxide (the mass ratio of chromium trioxide to activator is 100:30), mix them, put them into a ball mill jar, and ball mill them for 3 hours at 300r / min. The steps of weighing the materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0064] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 270℃ at a heating rate of 5℃ / min, and hold it at 270℃ for 24 hours.

[0065] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0066] Example 5

[0067] A chromium oxide composite material with added activator is prepared by the following steps:

[0068] 1) Weigh 30g of chromium trioxide (CrO3) and 3g of manganese dioxide (chromium trioxide and activator in a mass ratio of 100:10), mix them, and put them into a ball mill jar. Ball mill for 3 hours at 300r / min. The steps of weighing materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0069] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 280℃ at a heating rate of 5℃ / min, and hold it at 280℃ for 24 hours.

[0070] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0071] Example 6

[0072] A chromium oxide composite material with added activator is prepared by the following steps:

[0073] 1) Weigh 30g of chromium trioxide (CrO3) and 3g of manganese dioxide (the mass ratio of chromium trioxide to activator is 100:10), mix them, put them into a ball mill jar, and ball mill them for 3 hours at 300r / min. The steps of weighing the materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0074] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 290℃ at a heating rate of 5℃ / min, and hold it at 290℃ for 24 hours.

[0075] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0076] Example 7

[0077] A chromium oxide composite material with added activator is prepared by the following steps:

[0078] 1) Weigh 30g of chromium trioxide (CrO3) and 3g of manganese dioxide (the mass ratio of chromium trioxide to activator is 100:10), mix them, put them into a ball mill jar, and ball mill them for 3 hours at 300r / min. The steps of weighing the materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0079] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 300℃ at a heating rate of 5℃ / min, and hold it at 300℃ for 24 hours.

[0080] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0081] Example 8

[0082] A chromium oxide composite material with added activator is prepared by the following steps:

[0083] 1) Weigh 30g of chromium trioxide (CrO3) and 3g of manganese dioxide (the mass ratio of chromium trioxide to manganese dioxide is 100:10), mix them, put them into a ball mill jar, and ball mill them for 3 hours at 300r / min. The steps of weighing the materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0084] 2) Transfer the mixture obtained from ball milling into a tube furnace, and heat it to 300°C at a heating rate of 5°C / min under air atmosphere, and hold it at 300°C for 24 hours;

[0085] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0086] Example 9

[0087] A chromium oxide composite material with added activator is prepared by the following steps:

[0088] 1) Weigh 30g of chromium trioxide (CrO3) and 3g of lead dioxide (the mass ratio of chromium trioxide to activator is 100:10), mix them, put them into a ball mill jar, and ball mill them for 3 hours at 300r / min; the steps of weighing materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0089] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 270℃ at a heating rate of 5℃ / min, and hold it at 270℃ for 24 hours.

[0090] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0091] Example 10

[0092] A chromium oxide composite material with added activator is prepared by the following steps:

[0093] 1) Weigh 30g of chromium trioxide (CrO3) and 4.5g of vanadium pentoxide (the mass ratio of chromium trioxide to activator is 100:15), mix them, and put them into a ball mill jar. Ball mill at 300r / min for 3h. The steps of weighing materials and transferring them into the ball mill jar are carried out in a drying room with a temperature of 20-25℃, humidity of less than 1%, and dew point temperature of ≤-40℃.

[0094] 2) Transfer the mixture obtained from ball milling into a tube furnace, and under the protection of an oxygen atmosphere with an oxygen flow rate of 20 mL / min, heat it to 270℃ at a heating rate of 5℃ / min, and hold it at 270℃ for 24 hours.

[0095] 3) The product obtained by calcination in step 2) is transferred into a ball mill jar and pulverized at 300 r / min for 2 h. After passing through a 200 mesh sieve, the chromium oxide composite material with added activator is obtained.

[0096] Application Examples 1-10

[0097] The chromium oxide composite materials with added activators obtained in Examples 1-10 were used as positive electrode materials in the preparation of CR2032 coin cells. The specific steps included:

[0098] Electrode sheets were prepared by mixing the positive electrode material (chromium oxide composite material with added activator obtained in Examples 1-10), PVDF, and superconducting carbon black in a mass ratio of 8:1:1. First, the positive electrode material and superconducting carbon black were mixed evenly in a mortar. PVDF was pre-dispersed in NMP to prepare a 4wt% PVDF solution. The mixed positive electrode material and superconducting carbon black were transferred into a coating tube containing 4% PVDF solution and shaken on an oscillator for 18 min to obtain a positive electrode slurry. This slurry was then evenly coated onto a 16μm thick aluminum foil (coating thickness 100μm) and placed in a vacuum drying oven at 100℃ for 5 h. The resulting positive electrode sheet was punched into a 12mm diameter positive electrode sheet. The mass of the obtained positive electrode sheet and the blank aluminum foil were weighed and recorded. A lithium metal sheet was used as the negative electrode, polypropylene as the separator, and the electrolyte system was 1mol / L LiPF6 FEC:DMC = 3:7. CR2032 coin cells were assembled in an argon-filled glove box. The discharge curve is shown in [Figure number missing]. Figure 1 .

[0099] Comparative Example 1

[0100] A chromium oxide material is prepared using a method largely the same as in Example 1, except that the activator described in Example 1 is not added. The prepared chromium oxide material is then used as the positive electrode material to prepare a CR2032 coin cell, referring to the method described in the application example.

[0101] Comparative Example 2

[0102] A chromium oxide material is prepared using a method largely the same as in Example 8, except that the activator described in Example 8 is not added. The prepared chromium oxide material is then used as the positive electrode material to prepare a CR2032 coin cell, referring to the method described in the application example.

[0103] Figure 1 The figures show the discharge curves of five battery groups obtained from Application Example 1, Application Example 2, Application Example 3, Application Example 4, and Comparative Example 1 at a current density of 100 mA / g. Figure 1As can be seen, Comparative Example 1 has a discharge specific capacity of 314 mAh / g at a current density of 100 mA / g, while Application Example 2 has a discharge specific capacity of 357 mAh / g, an increase of 43 mA / g. The discharge specific capacities of Application Examples 3 and 4 are slightly lower than those of Comparative Example 1. This is because the discharge specific capacity of the activator itself is lower than that of the chromium oxide material. As the activator content in the composite material increases, the discharge specific capacity of the composite chromium oxide material will decrease.

[0104] Figure 2 The figures show the discharge curves of four battery groups (Application Examples 2, 5, 6, and 7) at a current density of 100 mA / g. Figure 2 It can be seen that the electrochemical performance of the obtained chromium oxide composite material gradually decreases with the increase of calcination temperature, indicating that the preparation temperature has a significant impact on the electrochemical performance of the obtained chromium oxide-based composite material.

[0105] Figure 3 To obtain the rate discharge curve of the CR2032 coin cell obtained in Example 2, from... Figure 3 It can be seen that the discharge specific capacity at a current density of 10 mA / g is 372 mAh / g. When the current density is increased to 100 mA / g, the capacity retention rate is 95.97%; when the current density is increased to 300 mA / g, the capacity retention rate is 81.4%; and when the current density is increased to 700 mA / g, the capacity retention rate is 68.2%. The chromium oxide composite material with added activator obtained in Example 2 has a significantly improved rate performance, and it can still maintain a very considerable capacity and voltage plateau even at high current discharge.

[0106] Figure 4 To apply the high-current discharge curves of the CR2032 coin cell obtained in Example 2 and Comparative Example 1, from... Figure 4 As can be seen, at a current density of 600 mA / g, the discharge specific capacity of the battery obtained in Example 2 is 325 mAh / g, while the discharge specific capacity of the battery obtained in Comparative Example 1 is 312 mAh / g; at a current density of 1500 mA / g, the discharge specific capacity of the battery obtained in Example 2 is 296 mAh / g, while the discharge specific capacity of the battery obtained in Comparative Example 1 is 229 mAh / g, and the voltage plateau of Comparative Example 1 is lower than that of Example 2. The chromium oxide composite material with added activator obtained in Example 2 has a significantly improved rate performance, and can still maintain a very considerable capacity and voltage plateau even at high current discharge.

[0107] Figure 5 This is a discharge curve of the CR2032 coin cell obtained in Example 8 and Comparative Example 2 at a current density of 100 mA / g. Figure 5 It can be seen that the discharge specific capacity of the battery obtained in Comparative Example 2 is lower than that in Example 8, indicating that the activator can still function in an air atmosphere.

[0108] Figure 6 The discharge curves of CR2032 coin cells obtained in Comparative Example 1, Example 2 (Application Example 2), Example 9 (Application Example 9), and Example 10 (Application Example 10) at a current density of 100 mA / g are shown. The results show that the discharge specific capacity of the battery obtained in Comparative Example 1 is lower than that of Examples 9 and 10.

[0109] Figure 7 The XRD patterns of the chromium oxide composite materials obtained in Example 2 and Comparative Example 1 are shown. The results indicate that the chromium oxide composite material obtained in Example 2 exhibits obvious diffraction peaks at 14.461°, 15.459°, 18.052°, and 22.341°, corresponding to the (060), (220), (240), and (310) crystal planes of Cr3O8, respectively, and there is no Cr8O 21 The obvious diffraction peaks indicate that the crystal form of the chromium oxide in the chromium oxide composite material obtained in Example 2 is consistent with Cr3O8; the chromium oxide material obtained in Comparative Example 1 shows obvious diffraction peaks at 15.243°, 17.925°, 19.868°, and 22.169°, corresponding to Cr8O8 respectively. 21 The (002), (0-12), (110), and (-1-12) crystal planes indicate that the chromium oxide in the chromium oxide material obtained in Comparative Example 1 is a transition crystal form Cr8O. 21 The above results indicate that the introduction of the activator described in this invention can effectively regulate the crystallization process of chromium oxide materials, making their crystal form closer to Cr3O8, which is beneficial to improving the electrochemical performance of the obtained chromium oxide-based composite materials.

[0110] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for using a chromium oxide composite material with added activator as the positive electrode active material of a lithium primary battery, characterized in that, The specific application steps include: mixing the positive electrode active material, conductive carbon and binder in a certain proportion to prepare a uniform slurry, and then setting it on the surface of a metal substrate to prepare a positive electrode sheet; the activator is a metal oxide-based electrochemical active material with a melting point higher than CrO3, namely MnO2; The mass ratio of CrO3 to activator is 100:(1~10); The preparation steps of the chromium oxide composite material with added activator include: 1) mixing chromium oxide CrO3 with activator and ball milling once; 2) calcining the mixed material obtained in step 1) at a temperature of 200~400℃; 3) ball milling the calcined product obtained in step 2) a second time, crushing and sieving to obtain the chromium oxide composite material with added activator. The calcination time is 6~24h.

2. The method according to claim 1, characterized in that, The activator has a melting point greater than 400°C.

3. The method according to claim 1, characterized in that, The ball milling rate in step 1) is 200~350 r / min, and the time is 2~5 h.

4. The method according to claim 1, characterized in that, The calcination atmosphere used in step 2) is air, argon, nitrogen or oxygen.

5. The method according to claim 1, characterized in that, The secondary ball milling rate in step 3) is 300~400 r / min, and the time is 2~5 h.

Images