Nickel-manganese composite hydroxide, method for producing the same, positive electrode active material for nonaqueous electrolyte secondary battery, method for producing the same, and nonaqueous electrolyte secondary battery

Abstract

Provided are a positive electrode active material that can provide a secondary battery extremely excellent in output characteristics and having sufficient volume energy density, a nickel-manganese composite hydroxide as a precursor thereof, and methods for producing these. A nickel-manganese composite hydroxide is represented by General Formula (1): NixMnyMz(OH)2+α and contains a secondary particle formed of a plurality of flocculated primary particles. The nickel-manganese composite hydroxide has a half width of a (001) plane of at least 0.40° and has an average degree of sparsity/density represented by [(a void area within the secondary particle/a cross section of the secondary particle)×100] (%) falling within a range of greater than 22% and up to 40%.

1 - 16 . (canceled) 
     
     
         17 . A positive electrode active material for a nonaqueous electrolyte secondary battery, the positive electrode active material comprising:
 a lithium-nickel-manganese composite oxide represented by General Formula (2): Li 1+t Ni x Mn y M z O 2+β     wherein in Formula (2), M is at least one additional element selected from Co, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W; t satisfies −0.05≤t≤0.5, x satisfies 0.1≤x≤0.9, y satisfies 0.05≤y≤0.8, z satisfies 0≤z≤0.8, and x+y+z=1.0; and β satisfies 0≤β≤0.5,   wherein the lithium-nickel-manganese composite oxide contains secondary particles, each of secondary particles being formed of a plurality of flocculated primary particles,   wherein the lithium-nickel-manganese composite oxide has an average void density (%) within the range of from 20% to 40%, the average void density being determined by obtaining a cross-section from each of 20 of the secondary particles having a particle size of at least 80% of a volume-average particle diameter MV of the secondary particles, determining a void area within the cross-section from each of the 20 of the secondary particles, determining an area of the cross-section from each of the 20 of the secondary particles, determining a void density for each of the 20 of the secondary particles according to an equation
   the void area within the cross-section of the secondary particle/the area of the cross-section of the secondary particle×100, and averaging the void density of the 20 of the secondary particles to obtain the average void density,
 
   wherein the positive electrode active material has a DBP absorption amount measured in compliance with HS K6217-4:2008 of greater than 28 cm 3 /100 g and up to 40 cm 3 /100 g, and   wherein [(D90−D10)/the volume-average particle diameter MV] as an indicator indicating a spread of particle size distribution of the positive electrode active material is at least 0.7.   
     
     
         18 . The positive electrode active material according to  claim 17 , wherein the positive electrode active material has a tap density of at least 1.2 g/cm 3  and up to 1.8 g/cm 3 . 
     
     
         19 . The positive electrode active material according to  claim 17 , wherein a ratio I(003)/I(104) of diffraction peak intensity I(003) of a 003 plane to peak intensity I(104) of a 104 plane by X-ray diffraction measurement is at least 1.7. 
     
     
         20 . A nonaqueous electrolyte secondary battery comprising a positive electrode comprising the positive electrode active material according to  claim 17 .