With the latest generation of high-end smartphones sporting power-hungry 5-inch screens, a growing number of phone vendors are emphasizing bigger batteries rather than thinner devices. After HTC's introduction of a 5-inch, full-HD screen on its Droid DNA phone, also know as Butterfly, Sony and Huawei Technologies showed similar products at International CES in Las Vegas and, on Tuesday, LG Electronics expanded its Optimus range with the G Pro.