What's holding energy tech back?

In this Jan. 14, 2011, photo provided by the Argonne National Laboratory, process engineer Bryant Polzin fills an 18650 lithium-ion battery cell with electrolyte using semi-automated equipment at Argonne's Cell Fabrication Facility in Lemont, Ill. To make the next breakthrough in battery technology, researchers have to master complex chemistry, expensive manufacturing, detailed engineering, a variety of different materials, lengthy testing, stringent safety standards, and giant cost problems.

Credit: AP Photo/Argonne National Laboratory, file