Evaluation of the Li(Al)/MnO_2 Couple in LiNO_3-KNO_3 Eutectic Electrolyte for Borehole Applications

摘要

The performance of MnO_2 cathodes in single cells with Li(Al) anodes was examined using the LiNO_3-KNO_3 eutectic electrolyte over a temperature range of 150° to 300°C at current densities from 7.6 to 30.4 mA/cm~2. This chemistry has the potential to be used in power sources for geothermal and borehole drilling applications. Kinetic limitations dominate at the low temperatures, while the highest temperature is close to that for exothermic reaction of the anode with the molten salt. Reasonable rates are possible in the intermediate temperature range. MnO_2 cathodes are much cheaper and more environmentally friendly than Ag_2CrO_4 cathodes for such applications, but with lower capacities. Full-sized battery tests are still needed to validate this technology.