In Situ Observation at the Zinc-Anode/KOH Electrolyte Interface by Grazing Incident X-ray Diffraction

Zinc-anode batteries are known for their high capacity and safety; however, the formation of dendrites has been a concern due to their adverse effect on cycle performance. In this study, we focused on the initial formation of dendrites and performed in situ measurements using surface-sensitive grazing-incidence x-ray diffraction measurement to evaluate the atomic structure at the electrode/electrolyte interface. During the 1st charge, the zinc was deposited in an orientation close to that of the electrode; however, during the 2nd charge after the 1st discharge, it was observed that non-oriented precipitation occurred and that the surface irregularities expanded. During the discharge, it was observed that the zinc was rotating and melting, suggesting that the zinc concentration near the zinc surface decreases, making it easier to dissolve at the root of the initial dendrite than at the tip. Therefore, we suggest that future zinc-anode battery research should focus on additives that promote mass transport to dissolve the initial dendrites from their tips.