Sion Power developed lithium-sulfur batteries that last much longer than standard lithium-ion batteries. We're hearing they'll power a tablet PC all the live-long day, compared to the six hours of a lithium-ion battery. But there's a catch. They're a lot heavier and they only last 60 charges until they're ready for the recycling center.
They're not due on the market until 2008, though, so there's plenty of time to work out those niggling little problems. Meanwhile, Intel is said to be sniffing around the company, perhaps interested in this super-long battery life for some of its devices even though these batteries are heavy as an anvil.