With this year's domestic lithium manganese acid LMO product rapid volume, more and more industry insiders began to focus on this market. It is understood that because the price of NCM in the first half of the year has been at a high level, many manufacturers in order to reduce the cost of materials, doping NCM with LOM is more, the current market is common from 9:1, 7:3, 8:2, 6:4 ratio, the application market is not the same, therefore, small make up with you to talk about LMO and NCM those things.
Currently, LMOS fall into three categories:
Layered lithium manganese oxide LiMnO2, theoretical capacity 285mA˙h/g, voltage platform 4V. Lamellar structure is difficult to synthesize, unstable, easy to generate Li2Mn2O4 spinel structure, resulting in voltage platform drop, poor stability, capacity irreversible attenuation, etc.
High voltage spinel LiMn2O4, theoretical capacity 148mA˙h/g, voltage platform 4.15. Poor performance at high temperature, serious capacity attenuation above 55℃. It is also easy to form Li2Mn2O4 spinel structure, resulting in voltage platform drop, poor stability, irreversible capacity attenuation and so on. This is what lithium manganate is currently used in industry.
Spinel lithium manganese oxide Li2Mn2O4, low voltage (3V), low capacity, poor circulation, are studying how to avoid this kind of thing.
In terms of ternary materials:
In order to solve the defects of lamellar lithium manganese oxide, LiNiCoMnO2(LiNiCoAlO2) was invented by doping metal elements with Ni and Co(Al) to replace manganese oxide. LiNiCoMnO2 takes into account the high capacity and high voltage of lithium nickel oxide, the high voltage and high safety of lithium manganese oxide, and the good circulation of lithium cobalt oxide. At the same time, it overcomes the disadvantages of difficult and unstable synthesis of lithium manganese and lithium nickel and high cost of lithium cobalt and becomes the mainstream cathode material at present. The theoretical capacity is 280mA˙h/g, and the voltage is 2.7~4.2. The actual capacity is about 160mA˙h/g.
LMO features:
LMO has no precious metals and prices are relatively low; NCM suffers from high cobalt price and high price (high nickel material can reduce BOM cost, but increase process cost).
LMO voltage plateau is high, 3.75~3.8V, NCM voltage plateau is low, 3.6~3.7V
LMO spinel structure, safety is relatively better; NCM layered structure, easy to mix lithium nickel, poor safety (the higher Ni%, the worse)
In the most critical gram capacity, LMO is lower and NCM is higher.
LMO high temperature performance is particularly poor, so the industrial use is LMO doped ternary. Typical examples are LMO: NCM=7:3(low cost, electric bicycle), 5:5 OR3:7, logistics vehicle
Total cost after adding LFP: pure LMO
More suitable for: ① cost sensitive; (2) Energy density has certain requirements; ③ Areas with low safety requirements, such as electric bicycles, low-speed vehicles, etc.
At present, the spinel lithium manganate produced by a few domestic companies can be circulated nearly 1000 times, with a capacity of 115mAh/g, and the price is only more than 60,000 yuan per ton. Compared with three materials, the price advantage is outstanding, and in the rate, lithium manganese has been dominant, safety is not to mention, three manganese mixing is to reduce the cost, the second is to pass the safety test. But the high temperature performance of lithium manganese is a problem, ternary compaction is better than lithium manganese.
