A calcium hydroxide interlayer as a selective separator for rechargeable alkaline Zn/MnO2 batteries

- The zincate concentration in the bulk electrolyte has been lowered and stabilized by Ca(OH)2 interlayers.
- XRD confirms the elimination of zinc manganese spinel phase.
- With no other expensive additives used, better capacity retention and a longer cycle life have been achieved.

Zinc poisoning of the cathode is a leading failure mechanism for rechargeable alkaline Zn/MnO2 batteries, as it leads to the formation of an electrochemically inactive zinc manganese spinel phase. In this communication, we report the use of calcium hydroxide sheets interlayered between zinc anodes and separators, which trap zincate ions through a complexing mechanism. Cells with such interlayers show favorable characteristics as compared with regular cells, such as lower zincate ion concentration in the bulk electrolyte, absence of undesirable spinel phase, and capacity retention above 90mAh/g-MnO2 after 60 cycles at 100% depth of discharge (DOD) of the 1st electron of MnO2.

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