Electrolytic manganese anode slime (EMAS) is a solid waste found in the anode chamber during the production of electrolytic manganese metal, which mainly contains high concentration of manganese and other impurities. In EMAS, gamma-MnO2 and delta-MnO2 turned into alpha-MnO2 after calcination, and the oxide can be dissolved by pickling. The results showed that the specific surface area of EMAS increased from 33.11 m(2).g(-1) to 93.53 m(2).g(-1), and the micropore volume increased from 0.0129 cm(3).g(-1) to 0.0362 cm(3).g(-1), as well as the specific capacity and the Open Circuit Voltage (OCV) of EMAS were 249.65 mAh.g(-1) and 1.60 V, respectively, under the condition of calcination temperature 400 degrees C, calcination time 1 h, sulfuric acid 1 mol.L-1, pickling temperature 25 degrees C, pickling time 0.5 h, and liquid-to-solid ratio 8:1.