Mobile PCs have come along in leaps and bounds in the last few years.  We've seen a lot of innovation in a lot of components, but batteries have not change much at all.  Battery life has improved, but that has been largely due to improvements in the amount of power the screen, hard drive and processor is using rather than how much the battery holds.  However Warner over at GottaBeMobile points to an advance in battery technology that may change all that.

The Energizer Bunny might keep going and going and going, but mobile pc users have been waiting and waiting and waiting for an advance in battery technology that will yield a jump in battery life. If researchers at South Korea’s Hanyang University have their say, we might just see that. They different approach involves silicon instead of graphite in making lithium batteries. That core change is supposed to yield 800% more storage capacity.

This can't come soon enough for me.  There are plenty of ultra portables that can give you 2 hours of battery life, so this advance could make all day computing in a small device a reality.