Analysis of the advantages and current situation of cathode materials for lithium manganese phosphate battery

First look at two recent reports on lithium manganese phosphate cathode materials: First, the Ningbo Institute of Materials of the Chinese Academy of Sciences announced that after two years of research and process exploration by the power and energy storage battery technology research team, high-performance manganese phosphate lithium battery cathode material has been developed. The second is at the just-concluded "AABC2012", GS Yuasa also announced the development of lithium manganese phosphate battery cathode material.

Like lithium iron phosphate battery, lithium manganese phosphate is also a phosphate-type lithium-based lithium battery cathode material. The safety and cycle life of this material is higher than that of the traditional layered structure cathode material lithium cobalt oxide and ternary material. . However, the potential of the widely used lithium iron phosphate 3.4V limits the increase in battery energy density, while lithium manganese phosphate has a high potential of 4.1V. Therefore, under the same capacity, the energy density of the lithium manganese phosphate battery can be increased by about 20% compared with the lithium iron phosphate battery.

The lithium manganese phosphate 18650 cylindrical battery produced by the Ningbo Institute of Materials of the Chinese Academy of Sciences has the following advantages compared with the lithium iron phosphate battery of the same type:

1. The discharge capacity is 1100mAh, the discharge voltage is 3.9 V, and the energy density is 20% higher.

2. The cycle life performance is good. After 150 cycles of 1C normal temperature cycle, the lithium battery capacity has no obvious attenuation.

3. High rate performance: The battery capacity retention rate of 40C continuous discharge is 90% of 1C.

4. Low-temperature performance: Discharge at 0.2C at -20 °C, and the capacity is 97.6% at normal temperature (25 °C). Even when discharged at -40 °C, the capacity can reach 61.5%.

5. Safety performance: through 3C-10V overcharge and puncture and other safety tests, no fire, no burning.

These good properties are due to the improvement of the materials passed by Ningbo materials, which solves the bottleneck of the difference in electronic conductivity and low lithium ion diffusion coefficient existing in lithium iron phosphate batteries. The material did not propose specific process measures, but GS Tang shallow said how to improve the energy density and electronic conductivity: 1. Cover the carbon on the lithium iron phosphate particles, 2. Construct a carbon network connecting the lithium manganese phosphate particles. Through these two measures, the capacity density is increased to 132mAh/g.

At present, lithium manganese phosphate is used as a cathode material for a new generation of high-energy-density power lithium battery. Once breakthroughs are made in research and development and low-cost large-scale preparation technology are formed, the market share of lithium iron phosphate battery will be seized, and the market space of lithium manganese phosphate battery and ternary lithium battery will be squeezed. In addition to the above two organizations, Swiss HPL and Sumitomo Osaka Cement Co., Ltd. also recently carried out research and development work on lithium manganese phosphate battery cathode materials.

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