Dry Goods: A Review of Lithium Iron Phosphate Production Processes!-Hezhong Environment (Beijing) Co., Ltd. was established in 2003

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Dry Goods: A Review of Lithium Iron Phosphate Production Processes!

Published Time:

2023-03-17

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Lithium iron phosphate (LFP) has diverse preparation processes, mainly divided into two mainstream processes: solid-state method and liquid-phase method. The solid-state method is currently the most mature and widely used method for LFP synthesis, while the liquid-phase method is more difficult and is currently only used by DNF in the market.

The solid-state method involves uniformly mixing iron, phosphorus, and lithium sources through mechanical milling, followed by high-temperature calcination to achieve carbon coating and produce LFP; its advantages include simple operation, low technical barriers, and low cost, making it the choice of most LFP companies.

Each LFP company will choose different raw materials as phosphorus and iron sources based on its own resource endowment and market conditions, further subdividing the solid-state method into iron phosphate method, ferrous oxalate method, and iron oxide red method. As the names suggest, the main difference between these three methods lies in the iron source used.

I. Iron Phosphate Method

Advantages: Mature technology, accounting for over 80% of LFP synthesis processes, easy process control, and high product capacity.

Disadvantages: Compared to the liquid-phase method, the material mixing is uneven, it is more dependent on the production capacity of the iron phosphate precursor and the quality of lithiation, the production cycle is long, and energy consumption is high.

Representative Companies: Hunan Yulong, Hubei Wanrun, Anda Technology, Fengyuan Lithium Energy.

II. Ferrous Oxalate Method

Advantages: Simple process, high compaction density of the resulting material, and less cycle attenuation.

Disadvantages: A large amount of ammonia, water, and carbon dioxide are generated during sintering, resulting in higher production safety risks. Particle size is difficult to control, distribution is uneven, morphology is irregular, and the synthesis process requires inert gas protection.

Representative Company: Hunan Shenghua Technology.

III. Iron Oxide Red Method

Advantages: The iron source is iron oxide, which is safer and cheaper than other processes. It can improve the conductivity of the material, the iron source is non-toxic and environmentally friendly, and the cost is lower. It has good low-temperature and high-rate performance.

Disadvantages: However, battery-grade iron oxide requires strict control of purity and particle size distribution, thus demanding high requirements for the iron oxide source.

Representative Company: Chongqing Te Rui.

The liquid-phase method can produce nano-scale or even molecular-level mixed precursors, but it is more complex to operate, with expensive production equipment and safety issues related to high-temperature and high-pressure equipment, resulting in higher synthesis costs and technological barriers.

Currently, only DNF uses the liquid-phase method, achieving molecular-level mixing of raw materials in the liquid phase, naturally evaporating water to obtain nano-scale precursor gel, and processing it through crushing, sintering, etc., to obtain nano-scale LFP.

Advantages: It can achieve nano-scale uniform mixing, materials are uniformly mixed in the liquid phase, the product consistency is high, and the quality is good.

Disadvantages: Production control is more difficult, and high equipment requirements are needed.

Representative Company: DNF.