Most batteries have a positive side and a negative side. But when it comes to rechargeable lithium ion batteries -- like the ones in laptops, cell phone and cars -- the negative goes beyond the anode or cathode.
First there's cost. Lithium ion batteries tend to be produced with an oxide of expensive metal, usually manganese, iron, cobalt, or nickel. Next, there's capacity. Lithium-ion batteries can be recharged only so much before they can no longer hold a charge.
But now, scientists at the Pacific Northwest National Laboratory figured out a way to improve cost and capacity by adding unlikely substances: soap and wax.
It came about when materials scientist Daiwon Choi, started thinking about capacity. He estimated that 30 percent of the loss was due to a property called resistance, that is, how easy (or not) it is for lithium ions and electrons to move through the metal oxide. A metal oxide made from smaller particles lined up evenly would create a path of least resistance.
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Like bakers in a kitchen, the scientists combined the ingredients -- the manganese, the wax and soap -- like a cake mix, and then heated it up. Under the heat, the manganese formed dense crystals that were distributed in a more even pattern, thanks to the wax and soap. Eventually, the wax and soap boiled off and the scientists were left with small "nanoplates" of lithium manganese phosphate, each approximately 50 nanometers thick.
Next, the researchers added a conductive carbon backing to the nanoplates, and put them to the test. The resulting mini battery had some strong points, performing especially well when charged and discharged slowly over the course of a couple days. They recently published the results (abstract) in Nano Letters.
In future experiments, the team will try affixing the carbon coating in different ways to see if that speeds up the charging and discharging rates to make the mini battery more ideal for consumer electronics. The advantage I see here is the possibility of simplifying construction to allow for cheaper battery materials. I'm a fan of using as little as possible to make the batteries work. In the electric vehicle world especially, rechargeable batteries still need a whole lot more spit and polish before we can go the distance with them.
Photo: Lithium manganese phosphate, made with help from wax and soap, can be used as cheaper electrodes for batteries. Credit: Pacific Northwest National Laboratory.
Tags: Batteries, Electricity, Green Electronics, Green Tech, Materials
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