What is Lithium Manganese Battery?

1. What is a Li-Mn Battery?

A Li-Mn battery generally refers to a lithium manganese dioxide (Li-MnO₂) battery, in which lithium serves as the negative electrode and manganese dioxide serves as the positive electrode.

These batteries offer excellent low- and medium-rate discharge performance, strong safety characteristics, and low cost. They are competitive with conventional batteries and were the first commercially successful type of lithium battery.

2. Manufacturing Process of Li-Mn Batteries

Using a fully sealed cylindrical winding Li-Mn battery as an example, the basic manufacturing process is as follows:

Step 1: Preparation of the Manganese Dioxide Positive Electrode

1. Mix heat-treated electrolytic manganese dioxide powder with acetylene black, polytetrafluoroethylene (PTFE) emulsion, and isopropyl alcohol in a specific ratio to form a uniform paste.

2. Coat the paste evenly onto a metal collector grid, then heat-treat and roll it to form the electrode.

3. Alternatively, the paste can be placed on both sides of the metal collector and pressed via a rolling machine.

4. Store the prepared electrodes in an environment with humidity below 2%.

Step 2: Preparation of the Lithium Metal Negative Electrode

1. Select lithium strips of the required thickness and width according to the battery model.

2. Cut the strips to the appropriate length.

3. Cold-weld electrode tabs onto the cut lithium strips.

4. Perform all operations in an environment with relative humidity below 2%.

Step 3: Preparation of the Separator

1. Use a dry polypropylene separator of the required thickness and width.

2. Store the separator in an environment with humidity below 2%.

3. A composite separator capable of sealing at 130–160 °C is typically selected.

Step 4: Preparation of the Li-Mn Battery Core

1. Wrap two layers of separator, slightly wider than the electrodes, around both sides of the manganese dioxide positive electrode to prevent contact with the lithium negative electrode.

2. Wind the layered electrodes into a cylindrical core using a winder.

3. Place the wound core into the battery casing.

Step 5: Preparation of the Electrolyte Solution

1. Electrolyte formulas vary by supplier, but the basic preparation involves mixing dehydrated lithium perchlorate with purified propylene carbonate, ethylene glycol dimethyl ether, and other components in a specific ratio.

2. Conduct all preparation in a dry-air environment with humidity below 2%.

Step 6: Injection and Sealing of the Electrolyte Solution

1. Weld the upper cover with glass insulators onto the battery shell containing the electrode core.

2. Inject the specified amount of electrolyte through the injection port using an injection machine.

3. Seal the injection hole with a steel ball via welding.

Advantages of LMO Batteries

• ·  High Power Capability: Excellent fast-charging and fast-discharging performance, delivering high operating voltage and energy output.

• ·  Thermal Stability: Good resistance to overheating, enhancing safety during operation.

• ·  Cost-Effective: Manganese, the primary material, is relatively inexpensive, making LMO batteries more affordable compared to other lithium-ion chemistries.

Disadvantages and Limitations of LMO Batteries

• ·  Rapid Capacity Fading: Capacity may decrease over time due to loss of electrical connections between nanoparticles and the current collector.

• ·  Limited Energy Density: Compared to some other lithium-ion chemistries, LMO batteries store less energy, which can restrict their use in high-capacity applications.

• ·  Temperature Sensitivity: Despite good thermal stability, performance can be affected under extreme temperature conditions.