8. The method for preparing a porous nickel-cobalt-manganese composite hydroxide according to claim 1, characterized in that: the dosage of the complexing agent is 1-20 g/L; the total molar ratio of the used precipitator to the nickel element, the cobalt element and the manganese element is 2: 1; the heating and stirring reaction is carried out at a rotating speed of 100-300 rpm and a temperature of 40-80 ℃ for 20-200 h.
dosage of the complexing agent
1-20 g/L
g/L
temperature
40-80 ℃
℃