Quartz Powder has been found to be a great additive for the electrolyte of lithium-sulfur batteries.
A problem with the Li-S chemistry is the loss of capacity when a battery made from these materials cycles. This is caused by polysulfides, which don't work in a battery, start taking up space on an electrode instead of working materials.
To solve this problem, researchers added quartz to the electrolyte because it binds with the polysulfides which keep them off the electrode.
This effect was found by happenstance when trying to study what is happing in this kind of cell. When they tried to x-ray the offending material, the polysulfides, they had to ground them so the x-rays could "see" them because the x-rays didn't work in a liquid. They used glass for this but found the improvement in overall performance was significant enough to push this idea as far as they could - thus quartz powder which is a large component of glass and has a great surface area.
If it can be made to work, the theoretical capacity of a Li-S battery is greater than that of the Li-Ion chemistry.
Atoms with problems work better
Frustrated atoms describe mixing up matrices of differing solids in order to create surface area and paths for electron transfer inside the combined result.
The idea is to take two different materials with atoms of different sizes and combine them so the internal structure doesn't fit together in such an orderly way. Because a material that has ordered atoms doesn't allow for electrons to reach the interior easily.
The obvious consequences are greater access to many parts of a material that would normally be blocked off by other parts of the material. And these paths to all parts of a material help with electron transport so not only is there more material access, but a cell with this construction would have a greater ability to charge/discharge faster.
Carbon nanotubes are a really great solution looking for problems to fix. And in battery labs, carbon nanotubes are being scrutinized closely because they continue to amaze researchers with how well they expose carbon to be used in just exactly the ways needed for good battery performance.
The latest from James Tour et al use the properties of carbon nanotubes coated with lithium with such a high surface area and low density that the anode can reach near the theoretical maximum of energy density!
The cathode will have to be brought up to speed to handing this high-performing anode, but take a look at the next story...
Plating for layersThin layers, like a coating of lithium just mentioned, is a big part of getting great performance out of batteries. But making thin and strong layers isn't always easy.
There is a way to make a thin layer that isn't very hard depending on the materials, and that is electroplating.
Electroplating is a way to get a coating on a substrate by drawing a material onto the substrate with an electrical charge. It doesn't work with every material so that is the trick to making it work for cells of the future.
This plating is being used on the anode side of a lithium battery and it potentially increases capacity and durability.
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