fuel cell

I'm planning to build myself an electric car. Due to the cost of Li-ion batteries, i would like to build myself a hi-density rechargeable, battery or fuel cell. So far, i have read about carbon based battery, salt, direct methanol fuel cell etc... which one would you recommend ?

http://www.lanl.gov/newsroom/news-releases/2013/June/06.04-catalyst-could-jumpstart-ecars.php For more information on the Lithium-Air battery: http://en.wikipedia.org/wiki/Lithium%E2%80%93air_battery...