Fast advances in computer technology, but not batteries, by Ashutosh Jogalekar.

Ever wondered why computers leap ahead at a great rate, with faster and smaller processors and huge advances in memory, while batteries get better only very slowly? Computing devices are so much better than those of five or ten years ago (known as Moore’s law), yet batteries hardly change. The Achilles heel in our mobile computing tech is obviously the batteries.

Why? Fred Schlachter from the American Physical Society: any kind of Moore’s Law for batteries may be limited by the fundamental chemistry inherent in a battery’s workings. This is unlike transistors, where finer lithography techniques have essentially enabled a repetitive application of miniaturization over the years.

The reason there is a Moore’s Law for computer processors is that electrons are small and they do not take up space on a chip. Chip performance is limited by the lithography technology used to fabricate the chips; as lithography improves ever smaller features can be made on processors. Batteries are not like this. Ions, which transfer charge in batteries are large, and they take up space, as do anodes, cathodes, and electrolytes. A D-cell battery stores more energy than an AA-cell. Potentials in a battery are dictated by the relevant chemical reactions, thus limiting eventual battery performance. Significant improvement in battery capacity can only be made by changing to a different chemistry.

Power versus information. Power scales with the size of the power device, but information processing can be miniaturized and has no particular relationship to the size of the device.

hat-tip Matthew