NOVELTY - Preparation of nickel, cobalt-mixer hydroxide (I) comprises providing a first and a second educt solution in a reactor, producing a homogeneous mixture in a reaction zone, precipitating the compound and producing a product suspension containing an insoluble product and mother liquor, partially separating the mother liquor of the precipitated product over the sloping plain, preparing a precipitated product suspension, whose concentration is higher than the stoichiometric concentration, removing the product suspension from the reactor and filtering and drying the precipitated product.    USE - (I), in the form of powder, is useful to prepare electrochemical cells and as an electrode material in the manufacture of fuel cells (claimed).    ADVANTAGE - The process exhibits very high space-time yield and is highly flexible. The reactor containing the sloping plain enables the process to provide multi-fold increase in the concentration of the solid material in the product suspension.    DETAILED DESCRIPTION - Preparation of nickel and cobalt-mixed hydroxide (I) of formula (NixCo1-x(OH)2) (where x is greater than 0 and less than 1) through precipitation comprises providing at least a first and a second educt solution in a reactor, producing a homogeneous mixture in a reaction zone in the reactor, precipitating the compound in the reaction zone and producing a product suspension containing an insoluble product and mother liquor, partially separating the mother liquor of the precipitated product over the sloping plain, preparing a precipitated product suspension, whose concentration is higher than the stoichiometric concentration, removing the product suspension from the reactor and filtering and drying the precipitated product. An INDEPENDENT CLAIM is included for a powdered nickel and cobalt-mixed hydroxide (A) exhibiting a Brunauer-Emmett-Teller surface of less than 20 m2/g, according to ASTM D 3663 and a tapping density of greater than 2.4 g/cm3, according to ASTM B 527.