Introduction

Conclusions

Micro Fuel Cells

Source: www.cnn.com

As small portable electronics increase in complexity, the power demands will soon overwhelm the capacity of the common lithium-ion battery. As a consequence, high tech manufacturers are interested in developing microfuel cells that would allow longer battery life and more compact power.

Unlike a typical lithium-ion battery, which is recharged using electricity, microfuel cells generate electricity. On of the most promising prototypes uses methanol as the power source. Methanol, commonly known as wood alcohol, can be bought in little canisters which can refill the device on the go. If used in conjunction with the lithium ion battery, a methanol fuel cell could extend the working time of a laptop from three hours to twenty-four hours.

The reactions at the anode and cathode proceed as follows:

Anode: CH3OH + H2O → CO2 + 6H+ + 6e-

Cathode: 6H+ + 6e- + 2/3 O2 → 3H2O

However, methanol is a toxic liquid, and thus less than ideal for portable electronics. Instead, some developers are looking at using ethanol, which is in all alcoholic beverages. Ethanol-run fuel cells often use enzymes to strip the hydrogen and produce an electric current. In theory, they could run off of vodka or gin.

Source: http://www.ch2bc.org

The ethanol micro fuel cell has a membrane coated with the enzyme alcohol dehydrogenase. This enzyme is responsible for breaking down ethanol in animal, bacteria, and yeasts.

Sources:

Ingram, LO et al. (1999) "Enteric bacterial catalysts for fuel ethanol production." Biotechnology Prog. 15(5):855-66.

Yen, T.J. et al. (2003) "A micro methanol fuel cell operating at near room temperature." Applied Physics Letter, 83(19): 4056-4058.