To improve the performance of these materials, Manthiram coated the particles with an electrically conductive polymer, which was itself treated with small amounts of a type of sulfonic acid. The coated nanoparticles were then incorporated into a small battery cell for testing. At slow rates of discharge, the materials showed an impressive capacity: at 166 milliamp hours per gram, the materials came close to the theoretical capacity of lithium iron phosphate, which is 170 milliamp hours per gram. This capacity dropped off quickly at higher discharge rates in initial tests. But Manthiram says that the new versions of the material have shown better performance.
It’s still too early to say how much the new approach will reduce costs in the manufacturing of lithium iron phosphate batteries. The method’s low temperatures can reduce energy demands, and the fact that it is fast can lead to higher production from the same amount of equipment–both of which can make manufacturing more economical. But the cost of the conductive polymer and manufacturing equipment also needs to be figured in, and the process must be demonstrated at large scales. The process will also need to compete with other promising experimental manufacturing methods, says Stanley Whittingham, a professor of chemistry, materials science, and engineering at the State University of New York, at Binghamton.
Manthiram has recently published advances for two other types of lithium-ion battery materials and is working with ActaCell, a startup based in Austin, TX, to commercialize the technology developed in his lab. The company, which last week announced that it has raised $5.58 million in venture funding, has already licensed some of Manthiram’s technology, but it will not say which technology until next year.