CN103401001A - High-energy battery - Google Patents

Abstract

The invention relates to a high-energy battery, comprising a negative electrode, a molten salt electrolyte and a positive electrode, characterized in that the molten salt electrolyte is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt or LiNO ₃ -KNO ₃ - KNO ₂ -Ca(NO ₃ ) ₂ quaternary nitric acid eutectic salt; the high-energy battery is a high-temperature lithium battery. Among them, the mass percent of LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt is LiNO ₃ 0-65%, KNO ₃ 30-95%, Ca(NO ₃ ) ₂ 0-60%; and LiNO ₃ and Ca(NO ₃ ) ₂ are not 0 at the same time; the mass percentage of quaternary nitric acid eutectic salt is LiNO ₃ 10-70%, KNO ₃ 1-55%, KNO ₂ 10-80%, Ca(NO ₃ ) ₂ 1~27.3%. The invention discusses the performance of the composed battery, and the result shows that the high-temperature lithium battery can be used in the temperature range of 150-350°C, and produces a higher open-circuit voltage and a higher initial discharge voltage platform.

Description

a high energy battery

technical field

The invention relates to a high-energy battery, in particular to a high-temperature lithium battery, which belongs to the field of thermal batteries and is mainly oriented to the application in the field of power supply technology with an operating temperature between 150°C and 350°C.

Background technique

In recent years, with the reduction of energy sources, people must explore deeper formations in order to find new oil resources; geothermal energy is stored underground and is not affected by climatic conditions. It can be used as both base load energy and peak load energy. can be used. Therefore, it is becoming increasingly important to develop a high-temperature power source for powering oil, gas and geothermal exploration equipment.

In the field of oil and natural gas exploration, the operating temperature of exploration equipment can be as high as 200°C, and as the exploration depth continues to deepen, the operating temperature will be higher; in the field of geothermal exploration, the operating temperature of exploration equipment is usually between 200°C and 400°C. As we all know, the current commercial battery operating temperature is -55°C to 70°C, the highest can reach 200°C; the battery commonly used in the military field is a thermal battery, and its operating temperature is as high as 350°C to 550°C; The high-temperature battery between 350°C is still blank. Other fields, such as automotive tire testing systems, underground pressure gauges, etc., have extensive demand for high-temperature batteries.

Due to its low potential and extremely low mass density, lithium metal has become an ideal first choice for improving battery operating voltage and specific energy density as anode materials. At present, the battery used in oil and gas deep drilling exploration equipment is an improved Li-Mg/SOCl ₂ battery, whose working temperature is limited to 180°C, manufactured by Battery Engineering, Inc. (Canton, MA). The working temperature in geothermal drilling may exceed 300°C. Currently, an expensive metal vacuum Dewar bottle is used to isolate the Li-Mg/SOCl ₂ battery from the surrounding high temperature environment, but it is also accompanied by a substantial increase in production costs. and massive energy consumption. Therefore, it is urgent to develop a new type of economical and practical high-temperature lithium battery to gradually replace the traditional and backward batteries, so as to solve the problem of stable power supply of exploration equipment in the working environment of 150°C to 350°C.

In order to solve this problem, there are two main methods: (1) learn from the existing thermal battery technology, modify and improve the thermal battery technology so that it can work at 150 ° C ~ 350 ° C; (2) find another way to develop an alternative New technology using metal vacuum Dewar bottle. Because thermal battery technology is very mature, and the risk of developing new technology is very high, after weighing, it is generally believed that choosing the first method is a more sensible choice.

Thermal battery, also known as heat-activated battery, is a primary battery that uses molten salt as an electrolyte and uses an internal heat source to make the battery temperature reach a predetermined operating temperature. Heating reserves and long-term storage are two characteristics of thermal batteries. Thermal batteries are very reliable and durable. If sealed well, the storage life can reach 25 years or more. In addition, thermal batteries have the advantages of high specific energy, high specific power, fast discharge rate, and wide operating environment temperature.

The main objective of the present invention is to learn from thermal battery technology to develop a class of high-energy batteries that are used in working environments around 150°C to 350°C, especially as one of the high-energy batteries—the development of high-temperature lithium batteries, and to build the battery of the present invention. idea.

Contents of the invention

Daily commercial lithium batteries can only work at -55°C to 70°C, while thermal batteries work at temperatures as high as 350°C to 550°C, neither of which can be used in a working environment around 150°C to 350°C. In order to overcome this technical problem, the present invention provides a reference thermal battery technology. The purpose of the present invention is to provide a type of high-energy battery that can work in a working environment of about 150°C to 350°C. The high-energy battery refers especially to high-temperature lithium battery.

The technical solution adopted in the present invention is: the high-energy battery (high-temperature lithium battery) includes a negative electrode, a molten salt electrolyte and a positive electrode. The negative electrode material is Li-Mg-B alloy, Li(B) alloy, Li(Si) alloy, Li(Al) alloy and other lithium alloys, but it is by no means limited to this; the electrolyte material is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt or LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ quaternary nitric acid eutectic salt; positive electrode material can be MnO ₂ , V ₂ O ₅ , PbO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , CrO ₂ , Ag ₂ CrO ₄ and other oxide cathode materials compatible with nitrate, but not limited thereto, where MnO ₂ , V ₂ O ₅ , LiMn ₂ O ₄ , CrO ₂ and Ag ₂ CrO ₄ is preferred.

The components and component mass percentages of the LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt are:

LiNO ₃ , 0～65%;

KNO ₃ , 30-95%;

Ca(NO ₃ ) ₂ , 0～60%;

More preferably, described nitric acid eutectic salt comprises components and component mass percentages are:

LiNO ₃ , 5～60%;

KNO ₃ , 40-90%;

Ca(NO ₃ ) ₂ , 1-30%.

Component and component mass percent of described quaternary nitric acid eutectic salt are:

LiNO ₃ , 10-70%;

KNO ₃ , 1～55%;

KNO ₂ , 10-80%;

Ca(NO ₃ ) ₂ , 1-27.3%.

More preferably, the components and component mass percentages included in the quaternary nitric acid eutectic salt are:

LiNO ₃ , 10-65%;

KNO ₃ , 1～50%;

KNO ₂ , 10～75%;

Ca(NO ₃ ) ₂ , 5-25%.

Described nitric acid eutectic salt has following advantage and effect relative to prior art:

(1) The melting point of the eutectic salt of ternary nitric acid in the present invention is lower than 150°C (the lowest can be lower than 110°C, which is 109.4°C), and the thermal stability temperature is higher than 500°C (the highest thermal weight loss starting point is 638°C). Wide temperature range, can be used normally in the temperature range of 150 ~ 500 ℃, good stability;

(2) The nitric acid eutectic salt of the present invention not only overcomes the shortcoming of the high melting point of the binary nitric acid molten salt system, but also solves the instability problem caused by the high-temperature oxidation and decomposition of the nitrate system and nitrite;

(3) The nitric acid eutectic salt of the present invention can not only be used as a molten salt electrolyte material for a high-energy battery, or as a medium material for heat transfer: as a molten salt electrolyte material for a high-energy battery, the nitric acid eutectic salt can be used as A molten salt electrolyte material that can work at 150°C to 500°C; as a heat transfer medium material, it has the advantages of low melting point and high thermal stability temperature, that is, a wide operating temperature window, which can improve the limitation of the temperature limit on the total efficiency of the Rankine cycle.

The eutectic salt of LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid described in the present invention has a melting point between 109.4°C and 150°C, a thermal stability temperature higher than 500°C (the highest thermal weight loss starting point is 638°C), and an operating temperature of wide range. Used as a material for the above two aspects, the performance is superior to existing materials.

The exothermic peak starting point of the quaternary nitric acid eutectic salt described in the present invention is lower than 125°C, and the starting point of thermal weight loss is higher than 500°C.

The technical advantage and effect that the present invention has:

(1) Using the above scheme, the prepared high-temperature lithium battery can be used in the temperature range of 150-350°C;

(2) The high-temperature lithium battery can produce a higher open circuit voltage and a higher initial discharge voltage platform, such as: Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /MnO ₂ battery, It can generate an open circuit voltage of 3.1-3.4V, and at a discharge rate lower than 10mA/cm ² , the initial discharge voltage platform can be higher than 2.90V.

The high-temperature lithium battery provided by the invention can be used in the temperature range of 150°C to 350°C, and the battery can generate a higher open-circuit voltage and a higher initial discharge voltage platform.

Table 1 and Table 1 are respectively LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt or quaternary nitric acid eutectic salt components, exothermic peak onset temperature and thermogravimetric onset temperature ( ℃). It should be emphasized that the two components of LiNO ₃ and Ca(NO ₃ ) ₂ in Table 1 are not 0 at the same time;

Table 1

Table 2

Description of drawings

Fig. 1 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 1;

Fig. 2 is the relationship curve of the ion conductivity and temperature of the nitric acid eutectic salt prepared in embodiment 1;

Fig. 3 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 2;

Fig. 4 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 3;

Fig. 5 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 4;

Fig. 6 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 5;

Fig. 7 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 6;

Fig. 8 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 7;

Fig. 9 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 8;

Fig. 10 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 9;

11 is a DTA-TG curve diagram of the eutectic salt of nitric acid prepared in Example 10.

Fig. 12 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 11;

Fig. 13 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 12;

Fig. 14 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 13;

Fig. 15 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 14;

Fig. 16 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 15;

Fig. 17 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 16;

Fig. 18 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 17;

Fig. 19 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 18;

Fig. 20 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 19;

Fig. 21 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 20;

Fig. 22 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 21;

Fig. 23 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 22;

Fig. 24 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 23;

Fig. 25 is the DTA-TG curve figure of the nitric acid eutectic salt prepared in embodiment 24;

Fig. 26 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /MnO ₂ single cell at 200°C and a discharge rate of 10mA/cm ² ;

Fig. 27 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /V ₂ O ₅ single cell at 200°C and a discharge rate of 10mA/cm ² ;

Fig. 28 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /MnO ₂ single cell at 250°C and a discharge rate of 10mA/cm ² ;

Figure 29 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /MnO ₂ single cell at 300°C and a discharge rate of 10mA/cm ² ;

Figure 30 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /MnO ₂ single cell at 150°C and a discharge rate of 10mA/cm ² ;

Figure 31 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /MnO ₂ single cell at 350°C and a discharge rate of 10mA/cm ² ;

Fig. 32 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ /MnO ₂ single cell at 200°C and a discharge rate of 10mA/cm ² ;

Fig. 33 is the voltage-capacity curve of a Li-Mg-B alloy/LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ /MnO ₂ single cell at 250°C and a discharge rate of 10mA/cm ² ;

Detailed ways

A. A nitric acid eutectic salt, the components and component mass percentages included in the nitric acid eutectic salt are as follows: LiNO ₃ , 0-65%; KNO ₃ , 30-95%; Ca(NO ₃ ) ₂ , 0 ~60%. This nitrate eutectic salt can be used not only as a molten salt electrolyte for high-temperature batteries, but also as a medium material for heat transfer.

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 23%; KNO ₃ , 62%; Ca(NO ₃ ) ₂ , 15%.

The raw materials used include LiNO ₃ , KNO ₃ and Ca(NO ₃ ) ₂ ·4H ₂ O, and the purity of the raw materials is >99%. Weigh 2.3g LiNO ₃ , 6.2g KNO ₃ , 2.16g Ca(NO ₃ ) ₂ ·4H ₂ O, and measure 150ml of deionized water; pour each weighed component into deionized water, stir evenly and Ultrasonic dissolution; heat the uniformly mixed solution to 100°C for distillation; put the solute left over from the distillation into a high-temperature furnace, melt it at 140°C for 16 hours, and then cool to room temperature with the furnace; grind the cooled solid into powder, Sieve, and then seal and store to obtain the desired eutectic salt of nitric acid.

Using STA449F3DSC/DTA-TG synchronous thermal analyzer to conduct DTA-TG test on the nitric acid eutectic salt prepared in this example at a heating rate of 10K/min. The DTA-TG curve obtained from the test is shown in Figure 1. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 113.4°C (that is, the melting point of the molten salt), and the peak value is 121.4°C; in order to determine the thermal decomposition more accurately Temperature, we take the starting point of thermogravimetric weight loss as the thermal decomposition temperature of the molten salt (that is, the thermal stability temperature). Figure 1 shows that the thermogravimetric starting point of the molten salt is around 628°C.

The electrical conductivity of the eutectic salt of nitric acid prepared in this example was tested, and the test results are shown in Figure 2. The ionic conductivity of the molten salt electrolyte is close to 0.07S/cm even at 150°C, and nearly 0.5S/cm at 300°C. The nitric acid eutectic salt has potential application value in the field of molten salt electrolyte.

Example 2

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 13%; KNO ₃ , 67%; Ca(NO ₃ ) ₂ , 20%.

The raw materials used include LiNO ₃ , KNO ₃ and Ca(NO ₃ ) ₂ ·4H ₂ O, and the purity of the raw materials is >99%. Weigh 1.3g LiNO ₃ , 6.7g KNO ₃ , 2.88g Ca(NO ₃ ) ₂ 4H ₂ O, and measure 150ml of deionized water; pour each weighed component into deionized water, stir evenly and Ultrasonic dissolution; heat the uniformly mixed solution to 100°C for distillation; put the solute left over from the distillation into a high-temperature furnace, melt at 300°C for 16 hours, and then cool to room temperature with the furnace; grind the cooled solid into powder, Sieve, and then seal and store to obtain the desired eutectic salt of nitric acid.

Using STA449F3DSC/DTA-TG synchronous thermal analyzer to conduct DTA-TG test on the nitric acid eutectic salt prepared in this example at a heating rate of 10K/min. The DTA-TG curve obtained from the test is shown in Figure 3. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 109.4°C (that is, the melting point of the molten salt), and the peak value is 122.6°C; the starting point of the thermogravimetric weight loss is around 611°C.

Example 3

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 18%; KNO ₃ , 64.5%; Ca(NO ₃ ) ₂ , 17.5%. Refer to Example 1 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 4. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 118.6°C (that is, the melting point of the molten salt), and the peak value is 122.6°C; The onset of thermogravimetric weight loss is around 576°C.

Example 4

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 28%; KNO ₃ , 59.5%; Ca(NO ₃ ) ₂ , 12.5%. Refer to Example 1 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 5. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 111.8°C (that is, the melting point of the molten salt), and the peak value is 119.4°C; The onset point of thermogravimetric weight loss is around 627.6°C.

Example 5

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 33%; KNO ₃ , 57%; Ca(NO ₃ ) ₂ , 10%. Refer to Example 1 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 6. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 111.6°C (that is, the melting point of the molten salt), and the peak value is 121.1°C; The onset of thermogravimetric weight loss is around 602°C.

Example 6

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 30.5%; KNO ₃ , 69.5%; Ca(NO ₃ ) ₂ , 0%. Refer to Example 1 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 7. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 131.8°C (that is, the melting point of the molten salt), and the peak value is 134.9°C; The onset of thermogravimetric weight loss is around 585°C.

Example 7

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 9%; KNO ₃ , 90%; Ca(NO ₃ ) ₂ , 1%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 8. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 133.3°C (that is, the melting point of the molten salt), and the peak value is 137.1°C; The onset of thermogravimetric weight loss is around 638°C.

Example 8

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 43%; KNO ₃ , 52%; Ca(NO ₃ ) ₂ , 5%. Refer to Example 1 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 9. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 111.7°C (that is, the melting point of the molten salt), and the peak value is 132°C; The onset of thermogravimetric weight loss is around 582°C.

Example 9

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 53%; KNO ₃ , 47%; Ca(NO ₃ ) ₂ , 0%. Refer to Example 1 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 10. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 131.2°C (that is, the melting point of the molten salt), and the peak value is 146.6°C; The onset of thermogravimetric weight loss is around 605°C.

Example 10

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 13%; KNO ₃ , 60%; Ca(NO ₃ ) ₂ , 27%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 11. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 121.4°C (that is, the melting point of the molten salt), and the peak value is 127.7°C; The onset of thermogravimetric weight loss is around 589°C.

Example 11

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 33%; KNO ₃ , 42%; Ca(NO ₃ ) ₂ , 25%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 12. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 147.7°C (that is, the melting point of the molten salt), and the peak value is 153.9°C; The onset of thermogravimetric weight loss is around 582°C.

Example 12

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 35%; KNO ₃ , 40%; Ca(NO ₃ ) ₂ , 25%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 13. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 145.3°C (that is, the melting point of the molten salt), and the peak value is 154°C; The onset point of thermogravimetric weight loss is around 578°C.

Example 13

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 60%; KNO ₃ , 40%; Ca(NO ₃ ) ₂ , 0%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 14. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 119.3°C (that is, the melting point of the molten salt), and the peak value is 140.6°C; The onset of thermogravimetric weight loss is around 573°C.

Example 14

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 5%; KNO ₃ , 80%; Ca(NO ₃ ) ₂ , 15%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 15. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 126.2°C (that is, the melting point of the molten salt), and the peak value is 134.9°C; The onset of thermogravimetric weight loss is around 595°C.

Example 15

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 0%; KNO ₃ , 90%; Ca(NO ₃ ) ₂ , 10%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 16. The test results show that the starting point of the first exothermic peak of the nitric acid eutectic salt is around 129°C (that is, the melting point of the molten salt), and the peak It is 134.3°C; the second exothermic peak (309.3°C) is caused by the phase transition of the nitric acid eutectic salt, but the TG curve does not decrease, which shows that it is still stable at this temperature; the starting point of thermogravimetric weight loss is at 632°C nearby.

Example 16

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 2.5%; KNO ₃ , 95%; Ca(NO ₃ ) ₂ , 2.5%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 17. The test results show that the starting point of the first exothermic peak of the nitric acid eutectic salt is around 128.8°C (that is, the melting point of the molten salt), and the peak The temperature is 134.9°C; the second exothermic peak (307.8°C) is caused by the phase transition of the nitric acid eutectic salt, but the TG curve does not decrease, which shows that it is still stable at this temperature; the starting point of thermogravimetric weight loss is 619°C nearby.

Example 17

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 15%; KNO ₃ , 35%; Ca(NO ₃ ) ₂ , 50%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 18. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 138.5°C (that is, the melting point of the molten salt), and the peak value is 147.5°C; The onset point of thermogravimetric weight loss is around 554°C.

Example 18

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 65%; KNO ₃ , 30%; Ca(NO ₃ ) ₂ , 5%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 19. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 112.2°C (that is, the melting point of the molten salt), and the peak value is 121.5°C; The onset of thermogravimetric weight loss is around 573°C.

Example 19

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 10%; KNO ₃ , 30%; Ca(NO ₃ ) ₂ , 60%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 20. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 138.5°C (that is, the melting point of the molten salt), and the peak value is 146.2°C; The onset of thermogravimetric weight loss is around 548°C.

Example 20

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 60%; KNO ₃ , 35%; Ca(NO ₃ ) ₂ , 5%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 21. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 112.2°C (that is, the melting point of the molten salt), and the peak value is 123.5°C; The onset point of thermogravimetric weight loss is around 561°C.

Example 21

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 10%; KNO ₃ , 80%; Ca(NO ₃ ) ₂ , 10%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 22. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 118.2°C (that is, the melting point of the molten salt), and the peak value is 135.1°C; The onset of thermogravimetric weight loss is around 594°C.

Example 22

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 10%; KNO ₃ , 90%; Ca(NO ₃ ) ₂ , 0%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 23. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 129.9°C (that is, the melting point of the molten salt), and the peak value is 139.8°C; The onset of thermogravimetric weight loss is around 629°C.

Example 23

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 15.5%; KNO ₃ , 54.5%; Ca(NO ₃ ) ₂ , 30%. Refer to Example 1 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 24. The test results show that the exothermic peak starting point of the nitric acid eutectic salt is around 117.4°C (that is, the melting point of the molten salt), and the peak value is 129.5°C; The onset of thermogravimetric weight loss is around 597°C.

Example 24

A nitric acid eutectic salt, which includes the following components and their mass percentages: LiNO ₃ , 20%; KNO ₃ , 40%; Ca(NO ₃ ) ₂ , 40%. Refer to Example 2 for the specific preparation method.

The DTA-TG curve of the nitric acid eutectic salt prepared in this example is shown in Figure 25. The test results show that the starting point of the exothermic peak of the nitric acid eutectic salt is around 143°C (that is, the melting point of the molten salt), and the peak value is 150.9°C; The onset of thermogravimetric weight loss is around 560°C.

B. A high-energy battery specifically refers to a high-temperature lithium battery, using lithium alloys such as Li-Mg-B alloys, Li(B) alloys, Li(Si) alloys, and Li(Al) alloys as battery negative electrode materials, and using LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ ternary nitric acid eutectic salt or LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ quaternary nitric acid eutectic salt as battery electrolyte material, and MnO ₂ , V ₂ O ₅ , PbO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , CrO ₂ , Ag ₂ CrO ₄ and other oxide cathode materials compatible with nitrates are used as battery cathode materials. This high-temperature lithium battery can work in an environment of 150-350°C, and shows good stability.

The present invention will be further described in detail below with reference to 25-32, 8 embodiments and accompanying drawings (Figs. 26-33), but the embodiments of the present invention are not limited thereto. It should be emphasized that due to space limitations, Examples 25-30 are just voltage-capacity curves under different conditions for a component in the LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt shown in Table 1. The determination of, and embodiment 31-32 is only to the determination result of 40-20-30-10 (No. 12) in 26 components shown in Table 2 under two different conditions. Those skilled in the art can obtain similar results for other components as molten salt electrolytes without creative efforts.

Example 25

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is MnO ₂ , and the electrolyte material is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ mass percent (23%-62%-15%) (Unless otherwise specified, the percentages used in this application are all mass percentages) nitric acid eutectic salt.

Use 0.4mm thick, 16mm diameter, and 0.083g Li-Mg-B (58%-4%-38%) alloy as the negative electrode; LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62% -15%) molten salt electrolyte mixed with MgO, kaolin or _SiO2 as a binder, melted at 300°C for 16 hours, ground, passed through a 100-mesh sieve, and pressed into a disc with a diameter of 15.5mm under a pressure of 296MPa As an electrolyte sheet; use 70% MnO2, 20% LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) molten salt electrolyte and 10% graphite (to increase conductivity) at 296MPa pressure Press down into a disc with a diameter of 15.5mm as the positive electrode sheet; use a 0.1mm thick, 20mm diameter 304 stainless steel sheet as the current collector.

The mass percentage of MgO, kaolin or SiO ₂ mixed with ternary nitric acid eutectic salt as binder is 35%:65%.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 200°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 26. The open circuit voltage of the single cell is about 3.25V, the initial discharge voltage platform is about 2.9V, and there are three discharge voltage platforms of about 2.65V, 2V and 1.2V.

Example 26

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is V ₂ O ₅ , and the electrolyte material is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) Eutectic salt of nitric acid.

Use 0.4mm thick, 16mm diameter, and 0.083g Li-Mg-B (58%-4%-38%) alloy as the negative electrode; use 35% MgO, kaolin or SiO ₂ binder and 65% LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) molten salt electrolyte is melted at 300°C for 16 hours, ground, passed through a 100-mesh sieve, and pressed into a diameter of 15.5mm under a pressure of 296MPa The disc is used as the electrolyte sheet; use 70% V ₂ O ₅ , 20% LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) molten salt electrolyte and 10% graphite (increase Conductivity) Under the pressure of 296MPa, it is pressed into a disc with a diameter of 15.5mm as the positive electrode sheet; a 0.1mm thick, 20mm diameter 304 stainless steel sheet is used as the current collector.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 200°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 27. The open circuit voltage of the single cell is about 3.6V, the initial discharge voltage platform is about 3.1V, and there are two discharge voltage platforms of about 2.8V and 1.3V.

Example 27

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is MnO ₂ , the electrolyte material is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) nitric acid co- molten salt.

Specific implementation method refers to embodiment 25.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 250°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 28. The open circuit voltage of the single cell is about 3.25V, the initial discharge voltage platform is about 2.8V, and there are three discharge voltage platforms of about 2.5V, 2.0V and 1.3V.

Example 28

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is MnO ₂ , the electrolyte material is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) nitric acid co- molten salt.

Specific implementation method refers to embodiment 25.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 300°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 29. The open circuit voltage of the single cell is about 3.25V, the initial discharge voltage platform is about 3.0V, and there are two discharge voltage platforms of about 2.75V and 2.2V.

Example 29

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is MnO ₂ , the electrolyte material is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) nitric acid co- molten salt.

Specific implementation method refers to embodiment 25.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 150°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 30. The open circuit voltage of the single cell is about 3.25V, the initial discharge voltage platform is about 2.6V, and there are two discharge voltage platforms of about 1.8V and 1.0V.

Example 30

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is MnO ₂ , the electrolyte material is LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ (23%-62%-15%) nitric acid co- molten salt.

Specific implementation method refers to embodiment 25.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 350°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 31. The open circuit voltage of the single cell is about 3.25V, the initial discharge voltage platform is about 2.9V, and there are three discharge voltage platforms of about 2.7V, 2.5V and 2V.

Example 31

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is MnO ₂ , and the electrolyte material is LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ (40%-20%-30% -10%) quaternary nitric acid eutectic salt.

Specific implementation method refers to embodiment 25.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 200°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 32. The open circuit voltage of the single cell is about 3.2V, the initial discharge voltage platform is about 2.9V, and there are three discharge voltage platforms of about 2.7V, 2V and 1.3V.

Example 32

A high-temperature lithium battery, the negative electrode material is Li-Mg-B alloy, the positive electrode material is MnO ₂ , and the electrolyte material is LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ (40%-20%-30% -10%) quaternary nitric acid eutectic salt.

Specific implementation method refers to embodiment 25.

Use the LAND CT2001A battery test system to test the discharge performance of the above-mentioned single battery at 250°C and a discharge rate of 10mA/cm ² . The test results are shown in Figure 33. The open circuit voltage of the single cell is about 3.25V, the initial discharge voltage platform is about 2.85V, and there are three discharge voltage platforms of about 2.6V, 2.0V and 1.1V.

In summary, the high-energy battery provided by the present invention also has the following characteristics:

① The exothermic peak starting point of the LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt is 109.4°C, and the thermal weight loss starting point is 638°C;

② The exothermic peak starting point of the quaternary nitric acid eutectic salt is 66.8°C, and the thermal weight loss starting point is 648°C;

③The exothermic peak starting point of nitric acid eutectic salt composed of 13LiNO ₃ —67KNO ₃ —20Ca(NO ₃ ) ₂ by mass percentage is 109.4°C, and the starting point of thermogravimetric weight loss is 611°C;

④The exothermic peak starting point of nitric acid eutectic salt composed of 23LiNO ₃ —62KNO ₃ —15Ca(NO ₃ ) ₂ is 113.4℃, and the starting point of thermogravimetric weight loss is 628℃;

⑤The thermogravimetric weight loss starting point of nitric acid eutectic salt composed of 9LiNO ₃ —90KNO ₃ —1Ca(NO ₃ ) ₂ is 638℃; the starting point of exothermic peak is 133.3℃;

⑥ The exothermic peak starting point of quaternary nitric acid eutectic salt composed of 10LiNO ₃ —10KNO ₃ —70KNO ₂ —10Ca(NO ₃ ) ₂ is 66.8℃;

⑦The starting point of thermogravimetric weight loss of quaternary nitric acid eutectic salt composed of 15LiNO ₃ —5KNO ₃ —75KNO ₂ —5Ca(NO ₃ ) ₂ is 648℃;

⑧ The negative electrode material is Li-Mg-B lithium alloy, Li(B) lithium alloy, Li(Si) lithium alloy or Li(Al) lithium alloy;

⑨The positive electrode material is an oxide compatible with MnO ₂ , V ₂ O ₅ , PbO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , CrO ₂ or Ag ₂ CrO ₄ nitric acid eutectic salt;

⑩Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /MnO ₂ single cell can produce an open circuit voltage of 3.1-3.4V at a discharge rate of 10mA/cm ² , and an open circuit voltage of less than 10mA/cm At a discharge rate of ² , the initial discharge voltage platform is higher than 2.90V;

Li-Mg-B合金/LiNO₃-KNO₃-Ca(NO₃)₂/V₂O₅单电池在10mA/cm²的放电速率下，可产生3.5～3.7V的开路电压，在低于10mA/cm²的放电速率下，初始放电电压平台高于3.0V；

Li-Mg-B alloy/LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ /V ₂ O ₅ single cell can produce an open circuit voltage of 3.5-3.7V at a discharge rate of 10mA/cm ² /cm ² discharge rate, the initial discharge voltage plateau is higher than 3.0V;

Li-Mg-B合金/LiNO₃-KNO₃-KNO₂-Ca(NO₃)₂/MnO₂单体电池在10mA/cm²的放电速率下，可产生3.1～3.5V的开路电压，在低于10mA/cm²的放电速率下，初始放电电压平台高于2.8V；

Li-Mg-B alloy/LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ /MnO ₂ single battery can produce an open circuit voltage of 3.1-3.5V at a discharge rate of 10mA/cm ² At a discharge rate of 10mA/cm ² , the initial discharge voltage plateau is higher than 2.8V;

1中LiNO₃-KNO₃-Ca(NO₃)₂硝酸共熔盐组分的质量百分比依次为23%-62%-15%，

中的LiNO₃-KNO₃-KNO₂-Ca(NO₃)₂四元硝酸共熔盐组分的质量百分比为40%-20%-30%-10%。Among them, ⑩ and

The mass percent of LiNO ₃ -KNO ₃ -Ca(NO ₃ ) ₂ nitric acid eutectic salt components in 1 is 23%-62%-15%,

The mass percent of the LiNO ₃ -KNO ₃ -KNO ₂ -Ca(NO ₃ ) ₂ quaternary nitric acid eutectic salt component in the mixture is 40%-20%-30%-10%.

Claims (10)

1. a high-energy battery, comprise negative pole, molten salt electrolyte and positive pole, it is characterized in that described molten salt electrolyte is LiNO ₃-KNO ₃-Ca (NO ₃) ₂Nitric acid congruent melting salt or LiNO ₃-KNO ₃-KNO ₂-Ca (NO ₃) ₂Quaternary nitric acid congruent melting salt; Described high-energy battery is High Temperature Lithium Cell.

2. high-energy battery as claimed in claim 1 is characterized in that:

1. described LiNO ₃-KNO ₃-Ca (NO ₃) ₂The constituent mass percentage of nitric acid congruent melting salt is:

LiNO ₃，0～65%；

KNO ₃，30～95%；

Ca (NO ₃) ₂, 0～60%; And LiNO ₃And Ca (NO ₃) ₂Two components are not 0 simultaneously;

2. the constituent mass percentage of described quaternary nitric acid congruent melting salt is:

3. high-energy battery as claimed in claim 1 or 2 is characterized in that:

1. described LiNO ₃-KNO ₃-Ca (NO ₃) ₂The mass percent of nitric acid congruent melting salt component is:

LiNO ₃，5～60%；

KNO ₃，40～90%；

Ca(NO ₃) ₂，1～30%；

2. the mass percent of described quaternary nitric acid congruent melting salt component is:

4. high-energy battery as claimed in claim 1 or 2 is characterized in that:

1. described LiNO ₃-KNO ₃-Ca (NO ₃) ₂The exothermic peak starting point of nitric acid congruent melting salt is lower than 150 ℃, and the thermal weight loss starting point is higher than 500 ℃;

2. the exothermic peak starting point of described quaternary nitric acid congruent melting salt is lower than 125 ℃, and the thermal weight loss starting point is higher than 500 ℃.

5. high-energy battery as claimed in claim 3 is characterized in that:

1. described LiNO ₃-KNO ₃-Ca (NO ₃) ₂The exothermic peak starting point of nitric acid congruent melting salt is lower than 150 ℃, and the thermal weight loss starting point is higher than 500 ℃;

2. the exothermic peak starting point of described quaternary nitric acid congruent melting salt is lower than 125 ℃, and the thermal weight loss starting point is higher than 500 ℃.

6. high-energy battery as claimed in claim 4 is characterized in that:

1. described LiNO ₃-KNO ₃-Ca (NO ₃) ₂The exothermic peak starting point of nitric acid congruent melting salt is 109.4 ℃, and the thermal weight loss starting point is 638 ℃;

2. the exothermic peak starting point of described quaternary nitric acid congruent melting salt is 66.8 ℃, and the thermal weight loss starting point is 648 ℃.

7. high-energy battery as claimed in claim 5 is characterized in that:

1. described LiNO ₃-KNO ₃-Ca (NO ₃) ₂The exothermic peak starting point of nitric acid congruent melting salt is 109.4 ℃, and the thermal weight loss starting point is 638 ℃;

2. the exothermic peak starting point of described quaternary nitric acid congruent melting salt is 66.8 ℃, and the thermal weight loss starting point is 648 ℃.

8. high-energy battery as claimed in claim 1 or 2 is characterized in that:

1. be 13LiNO by mass percent ₃-67KNO ₃-20Ca (NO ₃) ₂The exothermic peak starting point of the nitric acid congruent melting salt that forms is 109.4 ℃, and the weightless starting point of thermogravimetric is 611 ℃;

2. by 23LiNO ₃-62KNO ₃-15Ca (NO ₃) ₂The exothermic peak starting point of the nitric acid congruent melting salt that forms is 113.4 ℃, and the weightless starting point of thermogravimetric is 628 ℃;

3. by 9LiNO ₃-90KNO ₃-1Ca (NO ₃) ₂The weightless starting point of the thermogravimetric of the nitric acid congruent melting salt that forms is 638 ℃; The exothermic peak starting point is 133.3 ℃;

4. by 10LiNO ₃-10KNO ₃-70KNO ₂-10Ca (NO ₃) ₂The quaternary nitric acid congruent melting salt exothermic peak starting point that forms is 66.8 ℃;

5. by 15LiNO ₃-5KNO ₃-75KNO ₂-5Ca (NO ₃) ₂The weightless starting point of the thermogravimetric of the quaternary nitric acid congruent melting salt that forms is 648 ℃.

9. high-energy battery as claimed in claim 1 is characterized in that:

1. negative material is Li-Mg-B lithium alloy, Li (B) lithium alloy, Li (Si) lithium alloy or Li (Al) lithium alloy;

2. positive electrode is MnO ₂, V ₂O ₅, PbO ₂, LiCoO ₂, LiMn ₂O ₄, CrO ₂Or Ag ₂CrO ₄The oxide of nitric acid congruent melting salt compatibility.

10. high-energy battery as described in claim 1 or 9 is characterized in that:

1. Li-Mg-B alloy/LiNO ₃-KNO ₃-Ca (NO ₃) ₂/ MnO ₂Monocell is at 10mA/cm ²Discharge rate under, can produce the open circuit voltage of 3.1～3.4V, the initial discharge voltage platform is higher than 2.90V;

2. Li-Mg-B alloy/LiNO ₃-KNO ₃-Ca (NO ₃) ₂/ V ₂O ₅Monocell is at 10mA/cm ²Discharge rate under, can produce the open circuit voltage of 3.5～3.7V, the initial discharge voltage platform is higher than 3.0V;

3. Li-Mg-B alloy/LiNO ₃-KNO ₃-KNO ₂-Ca (NO ₃) ₂/ MnO ₂Cell is at 10mA/cm ²Discharge rate under, can produce the open circuit voltage of 3.1～3.5V, the initial discharge voltage platform is higher than 2.8V;

Wherein 1. and the LiNO 2. ₃-KNO ₃-Ca (NO ₃) ₂The mass percent of nitric acid congruent melting salt component is followed successively by 23%-62%-15%; 3. described LiNO ₃-KNO ₃-KNO ₂-Ca (NO ₃) ₂The mass percent of nitric acid congruent melting salt component is 40%-20%-30%-10%.

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