That black dot isn't a battery, it's an ultra-thin disc containing thousands of individual nanowire batteries. Rice University scientists claim their miniscule wires are "as small as such devices can possibly get," because each one comes complete with its own anode, cathode and gel-like electrolyte coating. This contrasts with previous examples we've seen, which bolted nanowires onto a chunky exterior cathode. On the other hand, these new all-in-one nano-batts only last for 20 charge cycles, so personally we're still betting on
