What are the advantages and disadvantages of ternary lithium batteries?
The advantages of ternary lithium batteries are: smaller size, higher capacity density, low-temperature resistance, and better cycle performance, making them the mainstream choice for new energy passenger vehicles. The disadvantages are: poor thermal stability, decomposing at 250-300℃, and the chemical reactions of ternary lithium materials are particularly intense. Once oxygen molecules are released, the electrolyte will burn rapidly under high temperatures, potentially leading to deflagration.
Ternary lithium batteries offer a relatively balanced performance in terms of capacity and safety, and possess excellent overall performance. The key functions, advantages, and disadvantages of these three metallic elements are as follows:
Co3+: Reduces the mixing and occupation of cations, stabilizes the layered structure of the material, lowers resistivity, increases conductivity, and improves cycle performance and speed. Ni2+: Can increase the capacity of the material (increase the energy density of the material volume). Due to the similar radii of Li and Ni, excessive Ni can also cause mixed discharge of lithium and nickel due to dislocations with Li and the concentration of nickel ions in the lithium layer. The larger the lithium content, the more difficult it is to deintertwine in the layered structure, resulting in poor electrochemical performance.
Mn4+ can not only reduce material costs but also improve the safety and stability of materials. However, if the Mn content is too high, a spinel phase is likely to form, which will destroy the layered structure and thus reduce the cycling capacity and decay.
High energy density is the biggest advantage of ternary lithium batteries. Voltage plateau is a crucial indicator of battery energy density, determining its basic efficiency and cost. An-time batteries and ternary lithium-ion batteries with higher voltage plateaus have longer lifespans. The discharge voltage plateau of a single ternary lithium battery is as high as 3.7V, compared to 3.2V for lithium iron phosphate and only 2.3V for lithium titanate. Therefore, from an energy density perspective, ternary lithium batteries are superior to lithium phosphate, lithium manganese oxide, or lithium titanate batteries, which have a clear advantage.
Poor safety and short cycle life are significant drawbacks of ternary lithium batteries, especially safety performance, which has become a major factor limiting their large-scale implementation and integrated application. Numerous practical tests have shown that high-capacity ternary batteries struggle to pass safety tests such as acupuncture and overload tests, which is why high-capacity ternary batteries typically incorporate more manganese or even use manganate salts.
II. What is the typical lifespan of a ternary lithium battery?
The theoretical lifespan of ternary lithium batteries is approximately 800 cycles, which is the average lifespan of commercially available rechargeable lithium-ion batteries. Lithium iron phosphate batteries last about 2,000 cycles, while lithium titanate batteries reach 10,000 cycles. Currently, traditional battery manufacturers have promised their ternary batteries specifications to be more than 500 times greater (under standard charging and discharging conditions), but after assembling the battery packs, due to issues with resistance, the relationship between resistance and internal resistance is not entirely identical, resulting in a lifespan of approximately 400 times greater.
