Cathode materials, process for the preparation thereof and secondary lithium ion battery using the cathode materials
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsTakeyuki Maegawa, Ayumi Nozaki, Fusaoki Uchikawa
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Abstract
A process of preparation capable of easily preparing cathode materials having a homogeneous composition in a good mass productivity, a cathode material obtained by this process, and a secondary lithium ion battery using the cathode material. Aqueous solutions of each of a lithium salt, a transition metal salt, and a complexing agent are prepared and mixed in a stoichiometric ratio of a cathode material, and therefrom water is removed by spray-drying to give a precursor which is then sintered. High performance secondary lithium ion batteries are obtained by using the obtained cathode material in the positive electrode.
Claims16
A process for preparing cathode materials comprising the steps of obtaining an aqueous solution consisting essentially of a water-soluble salt of lithium, a water-soluble salt of at least one transition metal element selected from Ni, Co, Mn and Fe and a complexing agent capable of forming a complex with said lithium and said transition metal element, wherein a composite complex is formed in said aqueous solution, removing a solvent of said aqueous solution by spray-drying the obtained aqueous solution without changing coordination of lithium ion and at least one transition metal ion to the complexing agent to give a precursor, and sintering said precursor.
A process for preparing cathode materials comprising the steps of obtaining an aqueous solution of a water-soluble salt of lithium, a water-soluble salt of at least one transition metal element selected from the group consisting of Ni, Co, Mn and Fe, and a complexing agent capable of forming a complex with said lithium and said transition metal element, spray-drying said aqueous solution at an atmospheric temperature of 160 to 220° C. to remove a solvent of said aqueous solution, thereby giving a precursor, and sintering said precursor.
A process for preparing a secondary lithium ion battery comprising the steps of:
- obtaining an aqueous solution consisting essentially of a water-soluble salt of lithium, a water-soluble salt of at least one transition metal element selected from Ni, Co, Mn and Fe and a complexing agent capable of forming a complex with said lithium and said transition metal element, wherein a composite complex is formed in said aqueous solution,
- removing a solvent of said aqueous solution by spray-drying the obtained aqueous solution without changing coordination of lithium ion and at least one transition metal ion to the complexing agent to give a precursor,
- sintering said precursor to give a cathode material,
- mixing said cathode material with a conductive material and a binder, coating the resulting mixture onto a positive electrode collector and drying the mixture to form a cathode material layer on said positive electrode collector, and
- interposing a separator containing an electrolyte between said cathode material layer and an anode material layer provided on a negative electrode collector.
Dependencies are inferred from the claim text.