The invention relates to a method for recycling 
metal ions from a waste 
lithium-
ion battery, belonging to the technical field of changing waste into resources. The method comprises the following steps of: (1) discharging the waste 
lithium-
ion battery, dismantling the battery to obtain the 
cathode material, carrying out MnP ultrasonic treatment on the 
cathode material, and then calcining and making into LiCoO2 
powder; (2) adding 
ascorbic acid, 
tartaric acid, or 
pyruvic acid and carrying out acid leaching on the LiCoO2 
powder to obtain leaching solution containing Li<1+> and Co<2+>; and (3) adding 
manganese and 
nickel salt into the leaching solution, mixing the leaching solution with LiOH solution, and synthesizing a ternary 
lithium-rich 
electrode material by a hydrothermal method. By adopting the method, the recycling and reuse of the 
electrode material of the waste lithium-
ion battery can be realized. Moreover, natural organic acids are adopted for treatment, the problems of secondarypollution caused by harmful gases and acid pickle generated in the traditional treatment with 
strong acids can be solved, and the whole process is simple, 
environmentally friendly and efficient.