Improved Low-Temperature Performance of Safer, Low-Cost Lithium Iron Phosphate Cathodes for Lithium-Ion Batteries

78339S Electric and hybrid electric vehicles are key technologies for reducing the nation¿s dependence on imported petroleum, reducing greenhouse-gas emissions and air pollution, and conserving petrochemical feedstocks. Lithium-ion batteries, with their high energy density, show promise to improve the performance of these vehicles. Lithium iron phosphate is an attractive cathode material for lithium-ion batteries for automotive applications because of its good safety, cost, energy density, cycle life, and calendar life. In this project a three-part study will be conducted to improve the lithium diffusivity in lithium iron phosphate. Synthesis and experimental analysis will be combined with quantum mechanical calculations to identify barriers to diffusion within the crystal structure of lithium iron phosphate, and chemical modifications will be undertaken to reduce those barriers. Part one of the study will identify synthesis techniques that improve lithium diffusion through the crystal structure of the lithium iron phosphate. Part two will use quantum mechanical calculations to identify substituents to the iron site which reduce the energy barrier for lithium diffusion. Part three will synthesize and test the most promising material identified in part two. Commercial Applications and Other Benefits as described by the awardee: Because of its great advantages in cost and safety relative to presently-used metal-oxide cathode materials, an improved lithium-iron-phosphate cathode would accelerate the introduction of lithium-ion batteries for hybrid electric vehicle applications. In a field currently dominated by a few Asia-based companies, this technology may allow the U.S. to reclaim large parts of the lithium-ion battery market.