Study on Cathode Material of High Temperature Manganese Dioxide Lithium Battery

Lithium Grid News: High-temperature lithium manganese dioxide batteries are an important primary power source and are widely used in automotive tire pressure measurement systems (TPMS) and medical instruments. Although my country is a big country in the manufacture of primary batteries, it is in a blank state in the field of high-end high-temperature primary lithium batteries. The lack of cathode materials suitable for high-temperature applications is one of the reasons that limit the development of high-temperature lithium manganese dioxide batteries. Above 100 ℃, the reaction between manganese dioxide and the electrolyte becomes stronger, which promotes the decomposition of the electrolyte and produces a large amount of gas, and the formation of an inert oxide layer on the surface of the manganese dioxide causes the ohmic polarization to increase. The performance of the manganese oxide battery deteriorates at high temperature and cannot work.

The company has conducted in-depth research on manganese dioxide cathode materials suitable for high-temperature use, starting with controlling the ratio of manganese dioxide γ and β crystal forms, and doping with elements to obtain high-temperature manganese dioxide ( G-MnO2).

Material performance test method:

Mix according to the ratio of high temperature manganese dioxide: conductive agent: adhesiveu003d92:4:4, with ethanol As a solvent, the positive electrode sheet is made by rolling film.

The obtained positive electrode sheet, lithium sheet, polypropylene separator, and electrolyte were assembled into a CR2032 lithium battery for testing.

Battery test results:

1. At room temperature (20±5 ℃), with a constant current (8-3-1.5-0.6- 0.3 mA/g) discharge, the cut-off voltage is 2.0 V, and the specific capacity of the cathode material is 264 mAh/g.

2. At low temperature (0±2 ℃), discharge at constant current stage (16-8-3-1.5-0.6-0.3 mA/g), discharge curve Subject to temperature fluctuations, the specific discharge capacity of the material is 261 mAh/g.

3. At a high temperature of 125 ℃, the battery is discharged at a constant current of 16 mA/g, with a cut-off voltage of 2.0 V, the battery can be discharged normally, the discharge curve is stable, and the cathode material The specific capacity is 260 mAh/g. Obviously, the high current discharge capability of the material is better at high temperature.

4. Leave the battery at 125 ℃ for 120 hours, then discharge at a constant current of 16 mA/g, the discharge cut-off voltage is 2.0 V, and the specific capacity of the positive electrode material is 250 mAh /g, indicating that the high-temperature cathode material remains relatively stable at 125 ℃, and the degree of decomposition or deterioration is small.

5. The battery was discharged at a constant current of 16 mA/g at 150 ℃, tested for 8 hours, and exceeded the TPMS system's requirement of working at 150 ℃ for 7 hours. The working voltage platform of the battery is normal, and there is no abnormal platform, indicating that the positive electrode material has no new phases, the nature is stable, and the battery can continue to discharge.

The CR2032 battery made of the high-temperature manganese dioxide material developed by our company has been tested for electrical performance at room temperature, low temperature and high temperature (125 ℃, 150 ℃). Putting aside the durability test, the specific capacity of this material reaches more than 260 mAh/g, the discharge curve is stable, and the manganese dioxide material remains relatively stable at high temperatures. This material is fully suitable for working at high temperatures and can be used as a positive electrode material for TPMS lithium batteries.