Better batteries by using less solvents good news for the environment

Here's an article that caught my eye and I thought you might be interested in reviewing it.

Basically, water could help make better batteries by using less solvent.  

Scientists have successfully used water to create a lithium-ion battery, which could reduce the overall cost of the commonly used technology by about one-eighth.

Currently, more than 80 percent of the costs of making lithium-ion batteries are due to materials and the processing of those materials. Scientists at Oak Ridge National Laboratory in Tennessee are now aiming to reduce the price of both of these factors.

All batteries generate electricity by flowing electric current between two electrodes — a positively charged cathode and a negatively charged anode. Cathodes make up about 70 percent of the total cost of high-power batteries, and the organic solvent used to make the lithium ion battery cathodes, N-methylpyrrolidone or NMP, is expensive, toxic and generates flammable vapors.

Making batteries with this solvent also requires expensive, explosion-proof processing equipment and costly solvent recovery and recycling systems.

Instead of using NMP, the researchers say they can replace it with a system that uses water, which is much safer, greener and at least 150 times cheaper than the organic solvent.

Replacing NMP with water is tricky because the slurries, or fluids containing the materials used to make the battery's electrodes, behaves in very different ways if water is employed. For instance, water-based slurries are typically not as good at coating the current collector, the material that gathers electric charge from the electrode.

"While it seems quite straightforward to substitute expensive and toxic NMP with water in battery manufacturing, it is very complicated and requires extensive knowledge in science and engineering to realize it," Li said.

The scientists employed a number of different tricks to get water to work. For instance, treating the current collector with electrified plasma alters its surface in ways that makes water-based slurries coat it better. Additives in the slurries also help prevent the particles from clumping together.