One of the most dangerous and expensive parts of making photovoltaic cells (solar panels) involves a substance called cadmium chloride. This toxic substance is not just expensive when bought in bulk, but carries with it loads of associated costs in handling and manufacturing. Working with cadmium chloride is necessary though, since it can be used to create a thin film that greatly boosts the efficiency of certain types of solar cells. Now, a substance called magnesium chloride has been found to grant the same boost in solar panel efficiency at a fraction of the cost, and with none of the concerns about safety and environmental impact.
Magnesium chloride is used in a variety of situations, from tofu production to de-icing roads. It’s safe for consumption and disposal in the environment — that’s another advantage over the cadmium version, which requires specialized disposal measures, or ironic corporate dumping scams. You’ll pay a health-fad premium for sodium-free magnesium salt at your local grocery store, but manufacturers can buy Mg-Cl for about $1 a kilogram, while cadmium chloride runs $300 for the same amount. Between reduced costs in materials, production, and recycling, this could be a big step toward bringing the costs of solar power to a mass-market level.
Yup. It really is just salt.
The scientists point out that in their solar cell efficiency tests, the cadmium salt film has to be applied under a fume hood with specialized equipment, while the magnesium salt was applied with a hobby sprayer on a desk in the middle of the lab. It’s so safe because it’s, well, sea salt. Brine from specific areas of the world, like the Dead Sea in Jordan and the Great Salt Lake in the United States, is evaporated away to leave salt behind, just as with regular sodium-based sea salts.
Remember: plants are still much better than us at capturing, storing, and using solar energy, and they don’t use a single space-age polymer to do it. Elegance and efficiency in design is all that’s really needed (along with perhaps a few billion years in which to experiment). Finding solutions like this one will be a necessary pat of switching to a cheap and abundant source of power worldwide.