Paraffin and surfactant oleic acid improve synthesis of lithium manganese phosphate electrodes

A little wax and soap can help build electrodes for cheaper lithium ion batteries, according to a study in August 11 issue of Nano Letters. The one-step method will allow battery developers to explore lower-priced alternatives to the lithium ion-metal oxide batteries currently on the market.

"Paraffin provides a medium in which to grow good electrode materials," said material scientist Daiwon Choi of the Department of Energy's Pacific Northwest National Laboratory. "This method will help researchers investigate cathode materials based on cheaper transition metals such as manganese or iron."

Consumers use long-lasting rechargeable lithium ion batteries in everything from cell phones to the latest portable gadget. Some carmakers want to use them in vehicles. Most lithium ion batteries available today are designed with an oxide of metal such as cobalt, nickel, or manganese. Choi and colleagues at PNNL and State University of New York at Binghamton wanted to explore both cheaper metals and the more stable phosphate in place of oxide.

The recharge tale

These rechargeable batteries work because lithium is selfish and wants its own electron. Positively charged lithium ions normally hang out in metal oxide, the stable, positive electrode in batteries. Metal oxide generously shares its electrons with the lithium ions.

Charging with electricity pumps electrons into the negative electrode, and when the lithium ions see the free-floating negative charges across the battery, they become attracted to life away from the metal oxide cage. So off the lithium ions go, abandoning the metal oxide and its shared electrons to spend time enjoying their own private ones.