100X Faster Charging Tech for Electric Cars, Smartphones

On Aug. 12, a research team headed by Dr. Ahn Do-cheon and Dr. Lee Kook-seung from Pohang Accelerator Laboratory announced that they succeeded in developing a positive and negative electrode material for lithium-ion batteries capable of conducting electricity 100,000 times faster. It was done by adding small amounts of silver to lithium manganese phosphate, which is drawing a lot of attention as a next-gen positive and negative electrode material for lithium-ion batteries.

Lithium manganese phosphate (LiMnPO4) has the same structure as lithium iron phosphate (LiFePO4), which is commonly used as an electrode material for lithium-ion batteries. The former is more efficient, since its energy density is high, stemming from its high operational electric potential. 

However, LiMnPO4 has not received much attention as an electrode material, as its conductivity is more than 100 times as low as LiFePO4, leading to low capacity and low power. Thus, to use it as an electrode material, it was necessary for the research team to increase the conductivity of LiMnPO4.

To accomplish the goal, they added silver in the amount of 1 percent of the total mass of LiMnPO4, and used a solid state synthetic method to create a LiMnPO4 electrode material with silver nanoparticles.

The research team found that the conductivity of LiMnPO4 with silver nanoparticles improved by  more than 100,000 times, since silver, which is one of the most conductive metals, exists between LiMnPO4 crystals with low conductivity, resulting in LiMnPO4 with silver nanoparticles having a highly-conductive structure.

After examining its electrochemical characteristics, the research team also discovered that LiMnPO4 with silver nanoparticles was able to generate more power, store much more energy, and last longer than the one without silver nanoparticles. In addition, LiMnPO4 with silver nanoparticles was found to be capable of producing power 100 times faster than LiMnPO4, when it was discharged within 6 minutes.

On top of that, a drastic improvement in the conductivity of LiMnPO4 was found to be possible as well, by adding small amounts of silver instead of using carbon, a conductor, thereby increasing energy density and energy per unit volume.

Dr. Ahn remarked, "This study is significant in that it has opened the possibility of commercializing LiMnPO4 as an electrode material for lithium-ion batteries by greatly improving its conductivity, after adding small amounts of silver to LiMnPO4 with low conductivity."

The research findings were first published online on July 7 by Nanoscale, a scientific journal published by the Royal Society of Chemistry, and the study was funded by the Ministry of Education and the National Research Foundation of Korea under the Project to Support Basic Research in Science & Engineering.