OLIVINE-TYPE COMPOUNDS: METHOD FOR THEIR PREPARATION AND USE IN CATHODE MATERIALS FOR SODIUM-ION BATTERIES

Olivine-type compounds, their preparation and use in cathode materials for sodium-ion batteries. The olivine-type compounds may be obtained by a direct synthesis embodying a hydrothermal method. The method may include preparing an aqueous mixture including a M-containing compound, a M′-containing compound and a M″-containing compound to obtain a M-M′-M″ mixture; adding a P-containing compound to the mixture M-M′-M″ mixture to obtain a M-M′-M″-P mixture; adding a Na-containing compound to the M-M′-M″-P mixture to obtain a Na-M-M′-M″-P mixture; and introducing the Na-M-M′-M″-P mixture into an autoclave to perform crystal growth and obtain the compound of general formula NaMM′M″PO.