Effect of vanillin to prevent the dendrite growth of Zn in zinc-based secondary batteries

Although considerable research efforts have been taken to minimize the dendrite growth of zinc in zinc-based secondary batteries, still dendrite growth is a severe issue, which needs further research in this field. In this paper, we have investigated that vanillin as an additive material either eliminates, or assist to minimize the formation of dendrite growth during the deposition of Zn. More than 300 cycles of charge-discharge curves are tested and even at relatively large current densities, dendrite-free zinc surfaces are observed with small amount of vanillin (0.5–5 mM). On the other hand, dendrite growth was observed in the vanillin-free solution. In order to observe the dynamic zinc deposition process on ultra-flat Au(111), we have used an advanced optical microscopy with differential interference microscopy which allowed us to follow the time dependent processes of deposition and dissolution of Zn at high speed accusation times (4~10 frames/sec even in large area of 100 × 100 μm). We also found that the formation of “black” films depends on the applied electrode potentials. It is anticipated that such insoluble films might be a key factor for the formation and growth of zinc dendrites in rechargeable zinc batteries.