The micro-porous Polytetrafluoroethylene (PTFE) and glass separators currently used in lithium oxyhalide batteries (LOHBs) have limitations in performance, lifetime, safety, and costs. A new separator technology is needed to improve performance, provide more energy-efficient battery geometries, decrease manufacturing complexity, and lower cost by increasing operational lifetime. LOHB reserve cells must utilize materials that: (a) provide electrical isolation between electrodes, (b) maximize volumetric efficiency for electrolyte capacity, (c) optimize efficient electrolyte flow and distribution when the battery is activated, and (d) are suitable for a production environment. The targeted materials chemistry will be capable of integration into other battery systems for military, aerospace and commercial applications. In Phase I, InnoSense (ISL) will demonstrate proof-of-principle of flexible ceramic separators capable of operating in extreme corrosive environments. We will demonstrate MDA-relevant separator performance. We will work closely with industrial partners to ensure smooth integration with LOHBs. In Phase II, ISL will develop and rigorously-test separator prototype establishing scale-up pathways. ISL will have separators tested in oxyhalide batteries for battery performance by our industrial partner. Phase III efforts, in collaboration with our partners, will include further engineering of the separator integrated with LOHB, field level tests and evaluation leading to hardware qualification.