There is interest in developing a suitable battery system that can be used at temperatures of 250 degrees C or less to power instrumentation used in oil/gas and geothermal boreholes. The discharge performance of MnO2 cathodes with Li-Mg-B alloy anodes is examined using the LiNO3-KNO3 eutectic electrolyte over a temperature range of 150 degrees C-300 degrees C at current densities from 10 to 30 mA cm(-2). In this study, we find that the cell can be activated at 150 degrees C and operate within the desired temperature range without any indication of possible hazards. However, we did observe that temperature and current density significantly affected cell capacity and voltage. Overall, the Li-Mg-B alloy/LiNO3-KNO3/MnO2 system shows great potential for powering instrumentation used in oil/gas and geothermal boreholes. (C) 2013 Elsevier B.V. All rights reserved.