Rechargeable Alkaline Zinc/Copper Oxide Batteries
Noah B. Schorr, David J. Arnot, Andrea M. Bruck, Jonathon Duay, Maria Kelly, Rachel L. Habing, Logan S. Ricketts, Julian A. Vigil, Joshua W. Gallaway, Timothy N. Lambert
Abstract
Resurrecting a battery chemistry thought to be only primary, we demonstrate the first example of a rechargeable alkaline zinc/copper oxide battery. With the incorporation of a Bi2O3 additive to stabilize the copper oxide-based conversion cathode, Zn/(CuO–Bi2O3) cells are capable of cycling over 100 times at >124 W h/L, with capacities from 674 mA h/g (cycle 1) to 362 mA h/g (cycle 150). The crucial role of Bi2O3 in facilitating the electrochemical reversibility of Cu2O, Cu(OH)2, and Cuo was supported by scanning and transmission electrochemical microscopy, cyclic voltammetry, and rotating ring-disc electrode voltammetry and monitored via operando energy-dispersive X-ray diffraction measurements. Bismuth was identified as serving two roles, decreasing the cell resistance and promoting Cu(I) and Cu(II) reduction. To mitigate the capacity losses of long-term cycling CuO cells, we demonstrate two limited depth of discharge (DOD) strategies. First, a 30% DOD (202 mA h/g) retains 99.9% capacity over 250 cycles. Second, the modification of the CuO cathode by the inclusion of additional Cu metal enables performance at very high areal capacities of ∼40 mA h/cm2 and unprecedented energy densities of ∼260 W h/L, with near 100% Coulombic efficiency. This work revitalizes a historically primary battery chemistry and opens opportunity to future works in developing copper-based conversion cathode chemistries for the realization of low-cost, safe, and energy-dense secondary batteries.