Batteries based on magnesium or calcium metal anodes have the potential to achieve energy densities exceeding current Li-ion batteries.  However, there are major challenges to overcome to make such a battery a reality.  One challenge is that currently no cathode materials have been identified that have sufficient energy density for a practical magnesium or calcium based battery.  Towards the end of finding higher energy density cathode materials, this poster presents two different materials approaches for the successful incorporation of Mg and Ca.  In particular, materials based on a Prussian blue type structure and with a polyanionic layered structure will be discussed.  Results presented include cycling performance, X-ray diffraction and X-ray based spectroscopies that prove intercalation of both Mg and Ca.  Comparing these classes of materials to others that have been shown to successfully intercalate Mg, yields insights into what makes a material a good candidate for future multivalent cathode research.  With these design principles guiding the search, a material that can achieve high energy densities for Mg or Ca chemistry can hopefully be found.