A search of relevant patents revealed that BYD applied for related patents as early as 2013, and subsequently applied for multiple patents for lithium manganese iron phosphate batteries in 2015, but there has been no further news since. It seems that after unveiling its lithium iron phosphate "blade battery" in 2020, BYD has not continued to pursue this path further.
Lithium manganese iron phosphate, an "upgraded version" of lithium iron phosphate?
Lithium iron phosphate (LFP) batteries, with their low cost, high safety, and long cycle life, have overtaken ternary lithium batteries and once again become the mainstream battery for new energy vehicles. Data shows that in August this year, the production of LFP batteries in the Chinese market was approximately 11.1 GWh, accounting for 56.9% of the total battery production in China; from January to August, the production of LFP batteries was approximately 58.1 GWh, accounting for 52.1% of the total battery production.
Technologies such as blade batteries and CTP (Cell-to-Pack) have improved the system integration efficiency and energy density of lithium iron phosphate (LFP) batteries, continuously meeting the needs of mid-to-high-end electric vehicles. However, from the perspective of LFP materials themselves, breaking through the performance "ceiling" of energy density and other aspects is not an easy task. Recently, lithium manganese iron phosphate (LFP) battery technology has been seen by many as a "Plus version" of LFP, attracting attention.
The reason why lithium manganese iron phosphate is considered an upgraded version of lithium iron phosphate is mainly because its energy density can be further improved.
Theoretically, lithium manganese iron phosphate (LMP) has a higher voltage platform than lithium iron phosphate (LFP). LMP can reach around 4.1V, while LFP operates at around 3.4-3.5V. Both have the same theoretical specific capacity. Due to its higher voltage, LMP has a theoretical energy density that is 15-20% higher than LFP under the same conditions. This is similar to current single-crystal, high-voltage ternary materials using nickel, which improve energy density through high voltage while maintaining the high safety and low cost of nickel-based materials.
In addition, the preparation process of lithium manganese iron phosphate is not much different from the existing lithium iron phosphate production system. The main problem is that its low conductivity needs to be solved by modification technologies such as coating, doping, and nano-sizing. There is no significant difference in cost between the two.
According to industry insiders, from a technical point of view, lithium manganese iron phosphate is not entirely a new technology. After lithium iron phosphate material was developed, some battery manufacturers made improvements based on different formulas, such as BYD mentioned above. However, its shortcomings in conductivity and cycle life deterred most companies in the past few years.
In addition, around 2015, my country's new energy vehicle subsidies were directly linked to the energy density of power batteries. At that time, lithium iron phosphate batteries were significantly inferior to ternary batteries in terms of energy density. Most car manufacturers and battery manufacturers focused their attention on ternary batteries, while lithium iron phosphate batteries were neglected. Research on lithium manganese iron phosphate batteries also decreased accordingly.
It can be seen that as lithium iron phosphate batteries have gained attention and become mainstream again due to their advantages in economy, safety and lifespan, lithium manganese iron phosphate, which also has advantages in energy density, safety and economy, is considered by many to be the main upgrade direction of lithium iron phosphate.
However, its shortcomings in conductivity, rate capability, and cycle life still require tangible technological improvements before it can be widely applied. Furthermore, the preparation of battery-grade manganese sulfate as a raw material is difficult and its quality varies, which is another bottleneck that needs to be overcome.
Lithium manganese iron phosphate has already been applied in the field of small power.
“Previously, subsidies for new energy vehicles were linked to energy density, so lithium iron phosphate and lithium manganese iron phosphate, which have lower energy densities, were not very popular. However, in the electric bicycle sector, which is not affected by subsidies, companies and users are more concerned about performance, and lithium manganese iron phosphate has become one of the key materials for companies’ research,” said Zhao Chenglong, Dean of the Battery Engineering Institute of Xingheng Power. He added that Xingheng Power has long-term research and application experience in composite technology of lithium manganese iron phosphate, such as blending lithium manganese oxide and lithium manganese iron phosphate, which has significantly improved the battery’s low-temperature performance, safety, and cycle life.
However, Zhao Chenglong also stated that lithium manganese iron phosphate is expected to continue to be used primarily in combination with other materials in the next two to three years.
The composite use of lithium manganese iron phosphate is also seen in ternary materials. According to industry insiders, coating ternary materials with lithium manganese iron phosphate can improve their safety performance, low-temperature performance, and cost, thereby expanding their application scenarios. In fact, this is already evident in some electric two-wheelers and power tools.
What are the prospects for lithium manganese iron phosphate used alone?
Undeniably, lithium iron phosphate has become the mainstream battery for new energy vehicles due to its advantages in terms of economy and safety. However, high-end models still prefer ternary batteries, especially high-nickel ternary batteries, which are clearly the main development direction of ternary batteries in the future.
The reason why lithium manganese iron phosphate has attracted attention is mainly because its energy density is about 15% higher than that of current lithium iron phosphate, but it is only close to that of NCM523, and the gap with high-nickel ternary batteries is very obvious.
Currently, lithium manganese iron phosphate only has a certain advantage in energy density compared to lithium iron phosphate, but its shortcomings are also obvious. To replace lithium iron phosphate, lithium manganese iron phosphate obviously needs to overcome many of its own shortcomings first.
In fact, the reason why everyone suddenly started discussing lithium manganese phosphate recently is mainly because some leading material companies have made new moves or progress in this area.
On September 3, Defang Nano announced that it plans to build a "100,000-ton-per-year new phosphate-based cathode material production base project" in Qujing Economic and Technological Development Zone. According to the company's patents, Defang Nano's lithium manganese iron phosphate products may utilize its unique liquid-phase process, resulting in advantages in product performance, consistency, and cycle life. Industry insiders speculate that this newly constructed project may be for lithium manganese iron phosphate products.
In addition, there are reports that Defang Nano's new type of lithium manganese iron phosphate has begun to send samples and is expected to be industrialized in 1-2 years. With the addition of positive electrode lithium replenishment technology, the energy density and cycle life of the battery have been significantly improved.
In addition, DangSheng Technology disclosed in its 2021 semi-annual report that the company is developing high-performance lithium iron phosphate and lithium manganese iron phosphate materials specifically for the electric vehicle and high-end energy storage markets.
In August of this year, Pengxin Resources issued an announcement stating that its wholly-owned subsidiary, Pengjia Fund, planned to invest 75 million yuan in Jiangsu Litai Lithium Energy Technology Co., Ltd. Pengxin Resources stated, "This investment is primarily driven by our confidence in Litai Lithium Energy's R&D and industrialization capabilities. Its main product, lithium manganese iron phosphate, has huge market potential and promising development prospects."
Looking at the performance characteristics of lithium iron phosphate, ternary materials, and lithium manganese iron phosphate, their respective application scenarios are relatively clear. However, their shortcomings are also clear. Lithium manganese iron phosphate currently "outperforms" lithium iron phosphate due to its energy density, but whether it can solve other shortcomings depends on the technological progress and development assessment of enterprises in this field.
