Abstract:
Provided is a cathode active material for a lithium secondary battery and a method for preparing the same. The cathode active material for a lithium secondary battery allows a lithium secondary battery to realize high capacity and to maintain maximum capacity even at high voltage, prevents a drop in capacity during repeated charge/discharge cycles, and improves the lifespan of a lithium secondary battery.
Abstract:
The present invention relates to a method for recycling LiFePO4, which is an olivine-based cathode material for a lithium secondary battery. The present invention is characterized in that a cathode material including LiFePO4 is synthesized using, as precursors, amorphous FePO4.XH2O and crystalline FePO4.2H2O (metastrengite) obtained by chemically treating LiFePO4 as an olivine-based cathode material for a lithium secondary battery, which is produced from a waste battery. Since a cathode fabricated from the LiFePO4 cathode material synthesized according to the present invention does not deteriorate the capacity, output characteristics, cycle efficiency and performance of the secondary battery and the cathode material of the lithium secondary battery may be recycled, the secondary battery is economically efficient.
Abstract:
Disclosed is a method of producing a nanocomposite cathode active material for a lithium secondary battery, represented by the following formula: xLi2MnO3—(1−x)LiMO2 wherein M is Nia—Mnb—Coc, x is a decimal number from 0.1 to 0.9, and a, b and c are independently a decimal number from 0.05 to 0.9. The method includes mixing a lithium compound with a manganese compound to prepare Li2MnO3 as a first cathode active material, mixing a mixed solution of nickel sulfate/manganese sulfate/cobalt sulfate, a sodium hydroxide solution and aqueous ammonia to prepare a coprecipitated hydroxide represented by (Nia—Mnb—Coc)(OH)2 wherein a, b and c are as defined above, mixing the coprecipitated hydroxide with a lithium compound to prepare a second cathode active material represented by LiMO2 wherein M is as defined above, and mixing the first cathode active material with the second cathode active material. The nanocomposite cathode active material has improved electrochemical properties, such as stability, electrode capacity and cycle life in the high-voltage region.