NOVELTY - Powdered mixed nickel-metal oxide-hydroxides with iron, cobalt, zinc, magnesium, calcium, strontium, lanthanum, cerium, yttrium and/or ytterbium as the other metal are new, where the D50 value of the particle size distribution is less than 5 microns and the ratio of tap density to D50 value is at least 0.4 g/cm3/micron.    USE - As active material for nickel-metal hydride batteries and as precursors for the production of lithium compounds for lithium secondary batteries (claimed). Also claimed is the use of such nickel-metal hydride batteries in hybrid and electric vehicles, solar mobiles and vehicles driven by fuel cells.    ADVANTAGE - The use of these compounds enables the production of secondary batteries with a high volumetric energy density and a high volumetric power density, and also batteries which can be used in hybrid and electric vehicles to provide a combination of high acceleration and long range.    DETAILED DESCRIPTION - Powdered compounds of formula NiaMbOx(OH)y (I) with    M = iron, cobalt, zinc, magnesium, calcium, strontium, lanthanum, cerium, yttrium and/or ytterbium    a = 0.6-1;    b = up to 0.4;    x = up to 0.60;    y = 1.4-2    are new, in which the D50 value of the particle size distribution (measured as in ASTM B 822) is less than 5 microns and the ratio of tap density (measured as in ASTM B 527) to this D50 value is at least 0.4 g/cm3/micron.INDEPENDENT CLAIMS are included for    (1) a method for the production of (I) by (a) making solutions of at least two starting materials, (b) mixing the solutions in a reactor and producing a homogeneous mixed reaction zone with a specific mechanical power input of at least 2 W/l and a product suspension comprising insoluble product and mother liquor with an alkaline excess of at least 0.12 mol/l obtained by adding excess alkali, and (c) removing some of the mother liquor from the precipitated product by using clarifiers or filter elements to give a suspension with a solid content of at least 150 g/l    (2) nickel-metal hydride batteries containing (I)    .