SBIR-STTR Award

Magnesium oxide (MgO) is in reserve thermal batteries as a binder in electrolyte pellets . MgO is normally made in large industrial quantities for commodity markets by the alkaline precipitation of magnesium hydroxide (Mg(OH)2) from natural brine solutions, followed by calcination at high temperature. Such commodity chemicals do not meet the needs of thermal batteries due to frequent product and process changes, and the technical function of MgO in separators. The strict requirements of MgO for thermal battery applications will be best met by a process which can be tightly controlled specifically for this use, and does not require a large physical plant. In this study, we will determine a reproducible synthesis route for Mg(OH)2 from high purity reagent grade feedstocks in the laboratory, produce MgO, and then elvaluate powder properties specifically for thermal battery applications. Potential follow-on work will scale-up the synthesis route to an appropriate scale, determine the optimum processing conditions for MgO to be used in thermal battery separators, and document the production process for use by domestic suppliers.

Keywords:
Magnesium Oxide, Magnesium Hydroxide, Thermal Battery, Electrolyte, Binder

A single, highly controllable, reliable production process is needed for the production of MgO with unique properties which is used to bind the electrolyte in activated reserve thermal batteries. In the Phase I program, EMF successfully demonstrated such a process for the preparation of Mg(OH)2, the essential precursor to the desired MgO. The Phase II program will complete the optimization of the precursor process as well as the calcination processes to yield the final product MgO. Design of Experiments (DOE) software will be used extensively during the project. Surface area by B.E.T., laser light scattering particle size analysis, and mercury intrusion porosimetry techniques will be used to characterize the materials. The optimum amount of MgO will be determined, using electrolyte-binder (EB) pellet deformation as a metric. LiSi/ EB /FeS2 cells and a 10-cell battery will be tested using the Phase II MgO product to demonstrate its efficacy.

Keywords:
Magnesium Oxide, Magnesium Hydroxide, Thermal Batteries