Tesla Inc (NASDAQ: TSLA) already has some of the most energy-dense electric vehicle batteries available, with the company's Model S able to travel over 400 miles on a single charge. Now it looks like Tesla's vehicles will be able to travel even farther, as a report from Reuters details Panasonic's (OTC: PCRFY) lans for future improvements. Over the next five years, Panasonic is planning to increase energy density by 20%, while also having cobalt-free batteries available in the next two to three years, according to Reuters. The 2170 cells that will be receiving these improvements are currently found in Tesla's...