Magnesium-calcium thin films at low calcium concentrations for anode materials in biodegradable implantable primary batteries

A Mg–Ca thin film combinatorial library was produced by thermal co-evaporation targeting a compositional spread of Ca from 0.2 to 3 at.%. Microstructure characterizations proved all alloys to have single-phase microstructures, displaying a gradual refinement with increasing Ca concentration. Electrochemical characterizations conducted using scanning droplet cell microscopy (SDCM), showed that the incorporation of Ca resulted in an improvement of the corrosion resistance of Mg thin films. The Mg-1.2 at.% Ca thin film alloy screened from the library showed an optimal initial cell potential and total discharge time.