How to understand the drawbacks of materials used in the production of lithium iron phosphate batteries.Nickel Metal Hydride No. 5 battery

　　Currently, lithium iron phosphate is widely chosen as the positive electrode material for power lithium-ion batteries in China. Market analysts from governments, research institutions, enterprises, and even securities companies are optimistic about this material and consider it as the development direction for power lithium-ion batteries. The main reasons for this are as follows: firstly, influenced by the research and development direction in the United States, Valence and A123 companies in the United States were the first to use lithium iron phosphate as the positive electrode material for lithium-ion batteries.

　　Secondly, there has been no domestic production of lithium manganese oxide materials with good high-temperature cycling and storage performance for power lithium-ion batteries. However, lithium iron phosphate also has fundamental defects that cannot be ignored, which can be summarized as follows:

　　1. During the sintering process of preparing lithium iron phosphate, there is a possibility of iron oxide being reduced to elemental iron under a high-temperature reducing atmosphere. Simple iron can cause micro short circuits in batteries and is the most taboo substance in batteries. This is also the main reason why Japan has not used this material as the positive electrode material for power lithium-ion batteries.

　　2. Lithium iron phosphate has some performance defects, such as low compaction density and compaction density, resulting in low energy density of lithium-ion batteries. The low temperature performance is poor, and even if it is nano sized and carbon coated, it does not solve this problem.

　　Dr. Don Hillebrand, Director of the Energy Storage System Center at the Argonne National Laboratory in the United States, described the low-temperature performance of lithium iron phosphate batteries as' terrible '. Their test results on lithium iron phosphate lithium-ion batteries showed that lithium iron phosphate batteries cannot drive electric vehicles at low temperatures (below 0 ℃). Although some manufacturers claim that the capacity retention rate of lithium iron phosphate batteries is good at low temperatures, that is when the discharge current is small and the discharge cutoff voltage is very low. In this situation, the device simply cannot start working.

　　3. The preparation cost of materials is relatively high compared to the manufacturing cost of batteries, resulting in low battery yield and poor consistency. Although the nanomaterialization and carbon coating of lithium iron phosphate have improved the electrochemical performance of the material, they have also brought other problems, such as reduced energy density, increased synthesis costs, poor electrode processing performance, and strict environmental requirements.

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