Wow! There aren’t too many things I see everyday that make me go wow ! This could be next big thing that might have a noticeable impact on how you and I work everyday and the possibilities are quite staggering if you think about it. But of course for now, I’ll be happy to have just quickly charging cell phones, laptops, mp3 players and hybrid cars that do not degrade in performance quickly if it is plugged in too long ! Grrr …
Here’s an excerpt from the article that talks a little about the physics involved:
A number of recent papers suggested that, in at least one lithium battery class (based on LiFePO4), the problem wasn’t the speed at which lithium moved—instead, it could only enter and exit crystals of this salt at specific locations. This, in turn, indicated that figuring a way to speed up this process would increase the overall performance of the battery.
To accomplish this, the authors developed a process that created a disorganized lithium phosphate coating on the surfaces of LiFePO4 crystals. By tweaking the ratio of iron to phosphorous in the starting mix and heating the material to 600°C under argon for ten hours, the authors created a material that has a glass-like coating that’s less than 5nm thick, which covers the surface of pellets that are approximately 50nm across. That outer coating has very high lithium mobility, which allows charge to rapidly move into and out of storage in the LiFePO4 of the core of these pellets. In short, because lithium can move quickly through this outer coating, it can rapidly locate and enter the appropriate space on the LiFePO4 crystals.
The results are pretty astonishing. At low discharge rates, a cell prepared from this material discharges completely to its theoretical limit (~166mAh/g). As the authors put it, “Capacity retention of the material is superior.” Running it through 50 charge/discharge cycles revealed no significant change in the total capacity of the battery.
Here are a few links on the same topic if you are hungry to learn more about it.