Regenerable Cu-intercalated MnO2 layered cathode for highly cyclable energy dense batteries

Manganese dioxide (MnO₂) – zinc (Zn) batteries have a rich 150 year old history dating back to its initial discovery by the famous French scientist Georges Leclanche. It once held of promise of being a breakthrough battery chemistry because of the theoretical energy density that it could store (>400Wh/L). However, the battery could not be made rechargeable because of the inherent problematic material properties of manganese dioxide. The battery could store the high energy density because of the high capacity of MnO₂ (617mAh/g), which it obtained through two electron reactions (This is famously called the 2nd electron capacity). However, in trying to access the 2nd electron capacity the MnO₂ would undergo deleterious reactions that would cause a breakdown in its crystal structure, which rendered the battery irreversible(not rechargeable). Hence, the chemistry was relegated to the realm of primary batteries for one time use in small applications like watch batteries, etc. This was a shame because the high energy density of these batteries were capable to be used for much larger and greener applications like electric vehicles, grid-scale storage,etc.

At the Energy Institute, Dr. Gautam G. Yadav and his team solved this 150 year old problem by tailoring the material properties of MnO₂ by creating a layered structure called birnessite (δ-MnO₂) intercalated with copper ions. This approach led to stabilizing the crystal structure and enhancing its electrochemical properties through its 2 electron reactions and thus, leading to its complete rechargeability with accessing the 2nd electron capacity for thousands of cycles. The promising outcome of this discovery is that this cheap(its raw materials are extremely cheap) and safe(aqueous-based) battery can be used for use large scale applications like grid-scale storage(the utilities market),etc. where the use of Li-ion batteries could be fatal because of its tendency to catch fire. In the paper, Dr. Yadav and his team have shown that very high energy densities >140Wh/L is obtained when paired with a zinc anode at 15% utilization. They also show that with modeling energy densities >250Wh/L is achievable when zinc utilization is increased to 35%.

Dr. Gautam G. Yadav’s discovery is a breakthrough in the field of alkaline batteries and this will enable cheaper, safer and energy dense aqueous-based batteries to be used for grid-scale storage applications.