Paula Hammond holds a piece of a fuel-cell membrane made using a layer-by-layer assembly technique. This method allows her to produce membranes that increase the power output of methanol fuel cells, making them more viable as an alternative to batteries for small electronics such as cell phones. Credit: Porter Gifford

In her lab at MIT, chemical-engineering professor Paula Hammond pinches a sliver of what looks like thick Saran wrap between tweezers. Though it appears un­remarkable, this polymer membrane can significantly increase the power output of a methanol fuel cell, which could make that technology suitable as a lighter, longer-­lasting, and more environmentally friendly alternative to batteries in consumer electronics such as cell phones and laptops.

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