Lithium Iron Phosphate Coatings Deposited by Means of Inductively-Coupled Thermal Plasma

Lithium-ion batteries have high energy efficiency and good cycling life and are considered as one of the best energy storage device for hybrid and/or electrical vehicle. Still, several problems must be solved prior to a broad adoption by the automotive industry: energy density, safety and costs. To enhance energy density and safety, the current study aims at depositing binder-free cathode materials using inductively-coupled thermal plasma. In particular, lithium iron phosphate (LiFePO4) coatings are deposited by solution precursor plasma spraying (SPPS) onto nickel current collectors. Under optimized SPPS conditions, results show that stable LiFePO4 olivine coatings are obtained and that their electrochemical reversibility is improved over sol-gel derived LiFePO4 cathodes. The LiFePO4 cathodes synthesized by SPPS are assembled in button cells and tested for energy capacity and cyclability. Further results related to the partial substitution of iron in the SPPS precursors (LiFe(1-x)M(x)PO4, where M = Mn, Co) are discussed.