Quite a few smartwatches are round, so why are they still using rectangular batteries? LG Chem certainly doesn't think that makes sense. It just started shipping a hexagonal battery that should deliver 25 percent more capacity in circular watches, where a lot of space normally goes to waste. You're theoretically getting another four hours of juice, or enough to make it through a long night without resorting to a low-power mode. The company isn't naming customers, but it's safe to say that LG's next wave of rounded wristwear will last that much longer. And that's just the start -- LG is planning more unusually-shaped batteries that will extend the running time of gadgets without dictating their look and feel.