1. Abstract<br />Pirolusit as main manganese mineral is found abundance and spread all over Indonesia. However, its main utilization is in metallurgy. While in other fields, such as chemical, industrial batteries, and medical, require high purity MnO2 in pirolusit. Therefore the high demands of MnO2 has to be supplied from abroad. Therfore there is a high need to do research on the processing pirolusit in order to add its value and benefit. In this research, hydrothermal processing with persulphate was used to purify pirolusit. Pirolusit was reacted with (NH4)2S2O8 0.5 M in hydrothermal conditions at a temperature of 140 ° C. To find the optimal results with this method, we carried out the hydrothermal time variation, of 36, 48, 60, and 72 hours. Optimization was also carried out by hydrothermal 36 hours over 3 times. The obtained product were characterised using Energy Dipersion Atomic Energy X-Ray (EDAX), X-Ray Floresence (XRF), gravimetric, and volumetric to determine the manganese content.It can be concluded that pirolusit after processing has a greater purity of MnO2. In addition, hydrothermal treatment makes pirolusit persulfate has a smaller particle size and more crystalline. While the optimum results obtained at the hydrothermal time of 60 hours. On the other hand, hydrothermal treatment of recurrent cause of MnO2 in pirolusit purer and smaller particle size. Although the purity of β-MnO2 obtained from t this research has not met the specification of lithium ion battery materials yet and the nano-order size has not yet achieved, β-MnO2 nano materials in the battery has a high stability of the structure so durability and its energy capacity will be larger. <br />Keywords: Pirolusit, Hydrothermal, Manganese, β-MnO2, Li -ion battery.<br />