Flexible eggshell membrane enabled dendrite-free Zn metal anode for aqueous zinc-ion batteries

Aqueous zinc ion batteries (AZIBs) are ideal choices for large-scale energy storage due to their outstanding merits of high safety and low cost. However, the severe dendritic growth on zinc anodes limits their further application. Artificial interface layer construction is an effective strategy to solve this problem. Here, the low-cost and easily prepared flexible eggshell membrane (ESM) is chosen as an interface protective layer to achieve a dendrite-free Zn anode. Compared with the bare Zn, the flexible ESM protected Zn anode affords better electrolyte wettability, more homogeneously distributed Zn2+ flux and much lower onset potential of hydrogen evolution, which are favorable for uniform and dense zinc deposition without formation of zinc dendrites. Our symmetric cell based on Zn@ESM electrode presents superior cycling stability of over 2000 h at 0.25 mA⋅cm−2 and over 4000 h at 0.5 mA⋅cm−2, while the symmetric cell with bare Zn only work less than 200 h. Moreover, the cycling stability of Zn@ESM//K1.14(VO)3.33[Fe(CN)6]2·6.8H2O full cell is also enhanced to retain 100% capacity after 600 cycles.