It's a little thicker than a regular cell phone but this prototype handset from Toshiba can last about 13 days on standby and then be recharged in seconds. It uses a direct methanol fuel cell, which produces electricity from a reaction between methanol, water and air. To recharge the battery, you simply squirt in more methanol.

Note: When you purchase something after clicking links in our articles, we may earn a small commission. Read our affiliate link policy for more details.
Shop Tech Products at Amazon