Progress Towards a Rechargeable Multivalent Battery

Cheaper batteries with higher capacity would increase the market penetration of electric vehicles and grid storage systems.  One way to achieve these gains in battery performance is to utilize a metal anode such as lithium, magnesium or calcium.  Lithium metal anodes have been extensively studied for decades, but still have not been commercialized.  On the other hand, comparatively little research has been performed on magnesium or calcium systems.  Magnesium metal has been shown to be less susceptible to the formation of dendrites than lithium.  No one is yet able to plate and strip calcium, however, it does possess a lower voltage than magnesium and a non-passivating oxide.  In order to rapidly explore the potential of these battery systems, we have developed techniques to study cathode materials without the need for a working metal anode.  In doing this we have determined that corrosion issues are more severe in these electrolytes than their lithium counterparts.  Furthermore, we have determined a class of materials that can intercalate Mg and Ca in nonaqueous electrolytes.  These materials are characterized by a combination of techniques including energy dispersive X-ray spectroscopy (EDX), X-ray absorption near-edge spectroscopy (XANES) and X-ray diffraction (XRD) to prove intercalation of the multivalent ion.  Additionally, we have made the first attempts to pair these materials with low voltage anode materials.  These anode materials include using Mg metal and metallic anodes that react with the multivalent ion.