主题：最近MIT的电池抄得热，单独发个文摘帖 -- 西潜1号

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.

But the truly surprising features of the cell came when the authors tweaked the cathode to allow higher currents to be run into the cell. Increasing the rate by a factor of 100 dropped the total capacity down to about 110mAh/g, but increased the power rate by two orders of magnitude (that's a hundred-fold increase) compared to traditional lithium batteries. Amazingly, under these conditions, the charge capacity of the battery actually increased as it underwent more charge/discharge cycles. Doubling the charge transport from there cut the capacity in half, but again doubled the power rate. At this top rate, the entire battery would discharge in as little as nine seconds. That sort of performance had previously only been achieved using supercapacitors.