Boeing, along with investigators in the United States and Japan, have focused on the lithium-ion battery from the start. And today’s announcement that the problem appears to have started with a short circuit within a cell is exactly what battery expert Dr. K.M. Abraham suggested was the problem when we spoke with him last month. The lithium-ion cells within the 787 batteries use a graphite-coated copper anode and a lithium cobalt oxide-coated aluminum cathode. The anode and cathode are separated by a very thin polyethylene film known as the separator.