Why do lithium batteries made of different materials have different voltages?

Electrode Potential Difference

The voltage in a lithium battery is determined by the electrode potentials of the materials used. Differences in electrode potentials lead to variations in the battery’s voltage. The positive electrode of a lithium-ion battery is typically made of lithium metal oxide, while the negative electrode is made of materials like graphite or carbon nanotubes. During charging and discharging, redox reactions occur between the positive and negative electrodes, generating voltage. The differences in the redox potential of various materials result in diverse battery voltages.

 

Material Type Differences

Different types of lithium batteries, such as lithium iron phosphate (LiFePO4), ternary lithium batteries, and lithium cobalt oxide (LiCoO2) batteries, have different voltages due to the materials used. For example, the nominal voltage of a lithium iron phosphate battery is 3.2V, while the nominal voltage of a ternary lithium battery and a lithium cobalt oxide battery is 3.7V. This is primarily because their positive electrode materials differ, which causes variations in the electrochemical potential, leading to different battery voltages.

 

Electrolyte Influence

Although different types of lithium batteries all use lithium salt electrolytes, the overall battery voltage can still vary due to differences in the positive and negative electrode materials. The electrolyte plays a key role in conducting ions within the battery, and its properties can affect the battery’s voltage performance.

Below are the nominal voltages of various types of lithium batteries:

  • Lithium Iron Phosphate (LiFePO4): 3.2V
  • Ternary Lithium Battery (NCM/NCA): 3.7V
  • Lithium Cobalt Oxide (LiCoO2): 3.7V
  • Lithium Manganese Oxide (LiMn2O4): 3.7V
  • Lithium Nickel Manganese Cobalt (LiNiMnCoO2): 3.6V – 3.7V
  • Lithium Titanate (Li4Ti5O12): 2.4V
  • Lithium Polymer (LiPo): 3.7V
  • Lithium Nickel Cobalt Aluminum Oxide (NCA): 3.6V – 3.7V
  • Lithium Phosphate Manganese (LiMnPO4): 3.2V
  • Sodium-Ion Battery (Na-ion): 3.0V – 3.3V
  • Solid-State Lithium Battery: 3.7V (varies depending on chemistry)

These are typical nominal voltages, although actual voltages can vary slightly based on the specific chemistry, design, and manufacturer of the battery.

 

Conclusion

Different types of lithium batteries have varying nominal voltages, mainly influenced by the materials used for the anode, cathode, and electrolyte. For instance, LiFePO4 batteries have a voltage of 3.2V, while ternary and LiCoO2 batteries typically have 3.7V. Choosing the right battery type and voltage is crucial for optimizing performance and ensuring safety.


Post time: Dec-23-2024