Disclosed herein are methods for extracting one or more metals from a material, wherein the method includes: contacting the material with an acidic aqueous solution having a pH less than 7, and reducing, with an alkyl carbonate, one or more metal oxides selected from nickel oxide, cobalt oxide, and manganese oxide; where the material includes the one or more metal oxides. Also disclosed are methods including extracting one or more metals from a material to obtain an aqueous solution comprising metal ions, and separating the metal ions to obtain at least one essentially pure metal ion solution and/or at least one essentially pure solid metal ion salt. Further disclosed are methods for recycling at least one battery material selected from a lithium ion battery, lithium ion battery waste, lithium ion battery production scrap, lithium ion cell production scrap, lithium ion cathode active material, and combinations thereof.

A method for recycling lithium batteries containing the steps: (a) digesting comminuted material (10), which contains comminuted components of electrodes of lithium batteries, using concentrated sulphuric acid (12) at a digestion temperature (T.sub.A) of at least 100 C., in particular at least 140 C., so that waste gas (14) and a digestion material (16) are produced, (b) discharging the waste gas (14) and (c) wet chemical extraction of at least one metallic component of the digestion material (16).