The electrochemical behaviour of B(Pb)SCCO 2212-doped Zn electrode for Ni-Zn battery applications

The conductive cuprate ceramic Bi _1.7 Pb _0.3 Sr₂CaCu₂Oₓ (B(Pb)SCCO 2212) has been employed as a functional additive for the zinc electrode in alkaline Ni-Zn batteries in order to improve electrochemical performance and cycling stability. Our study focuses on the electrochemical mechanisms by which this additive performs in a 7M KOH electrolyte, simulating the battery environment. Cyclic Voltammetry (CV) and Chronopotentiometry (CP) were used to elucidate the redox processes occurring during the electrochemical cycle. The obtained results reveal that the B(Pb)SCCO 2212 ceramic undergoes reduction during the charging process at potentials significantly higher than that those associated with the main ZnO reduction reaction. The CV curves have shown distinct cathodic peaks corresponding to the reduction of bismuth and copper ions to their metallic states. This in-situ formation of a conductive metallic network within the electrode matrix prior to zinc deposition could become a key factor to improve entire battery performance (is suggested to play a crucial role in enhancing the overall battery performance). The observed reduction potentials for B(Pb)SCCO 2212 showed higher values than that of the potential for ZnO reduction (approx. -1.5 V vs. SCE), confirming that the percolation B(Pb)SCCO 2212 network is established first, promoting uniform current distribution and enhancing the еlectrode’s overall kinetics.