Continuous Synthesis of Carbon-Coated Lithium-Iron-Phosphate

• Main Authors: METZ HANS JOACHIM, WASER OLIVER, BUECHEL ROBERT, PRATSINIS SOTIRIS E
• Format: Patent
• Language: English
• Published: 05.07.2012
• Subjects: BASIC ELECTRIC ELEMENTS; CABLES; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; CONDUCTORS; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRICITY; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; INSULATORS; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; METALLURGY; NANOTECHNOLOGY; PERFORMING OPERATIONS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING ORDIELECTRIC PROPERTIES; SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING

The invention relates to a continuous process for preparing carbon-coated lithium-iron-phosphate particles, wherein the carbon-coated lithium-iron-phosphate particles have a mean (d50) particle size of 10 to 150 nm, and wherein the carbon-coating is an acetylene-black coating, comprising performing in a reactor a flame-spray pyrolysis step (i) in a particle formation zone of the reactor, and a carbon-coating step (ii) in a carbon-coating zone of the reactor, wherein in (i) a combustible organic solution containing a mixture of lithium or a lithium compound; iron or an iron compound; and phosphorus or a phosphorous compound in an organic solvent, is fed through at least one nozzle where said organic solution is dispersed, ignited and combusted, to give a flame spray thereby forming an aerosol of lithium iron phosphate particles; (ii) acetylene gas is injected into said aerosol thereby forming an acetylene-black coating on the lithium iron phosphate particles; (iii) the coated particles are cooled by an inert quench gas and collected on a filter.