Advantages and disadvantages of ternary lithium battery
The ternary lithium battery is relatively balanced in terms of capacity and safety, and is a battery with excellent comprehensive performance. The main functions and advantages and disadvantages of the three metal elements are as follows:
Co3+: Reduce cation mixed occupation, stabilize the layered structure of the material, reduce the impedance value, improve the electrical conductivity, and improve the cycle and rate performance.
Ni2+: It can improve the capacity of the material (increase the volume energy density of the material), and due to the similar radius of Li and Ni, too much Ni will also cause the dislocation phenomenon with Li to cause the mixed arrangement of lithium and nickel, and the concentration of nickel ions in the lithium layer The larger it is, the harder it is for lithium to be deintercalated in the layered structure, resulting in poor electrochemical performance.
Mn4+: Not only can reduce the material cost, but also can improve the safety and stability of the material. But too high Mn content will easily appear spinel phase and destroy the layered structure, reduce the capacity and decrease the cycle.
High energy density is the biggest advantage of ternary lithium batteries, and voltage platform is an important indicator of battery energy density, which determines the basic performance and cost of the battery. The higher the voltage platform, the greater the specific capacity, so the same volume, weight, even the same An hour's battery has a longer battery life than a ternary material lithium battery with a higher voltage platform. The discharge voltage platform of single ternary lithium battery is as high as 3.7V, lithium iron phosphate is 3.2V, and lithium titanate is only 2.3V. Therefore, from the perspective of energy density, ternary lithium battery is better than lithium iron phosphate, lithium manganate or lithium iron phosphate. Lithium titanate has absolute advantages.
Poor safety and short cycle life are the main shortcomings of ternary lithium batteries, especially safety performance, which has been a major factor limiting its large-scale configuration and large-scale integrated applications. A large number of actual measurements show that it is difficult for a ternary battery with a large capacity to pass safety tests such as acupuncture and overcharge, which is why more manganese is generally introduced into large-capacity batteries, or even mixed with lithium manganate. The cycle life of 500 times belongs to the middle and lower part of the lithium battery, so the main application field of ternary lithium battery is 3C digital and other consumer electronic products.
