Highly Zn2+-conductive and robust modified montmorillonite protective layer of electrodes toward high-performance rechargeable zinc-ion batteries

The corrosion, parasitic side-reaction and dendrite of Zn anode as well as the dissolution of MnO2 cathode limit the commercial application of zinc-ion batteries (ZIBs). Herein, a novel coating layer on Zn anode and MnO2 cathode of rechargeable ZIBs is rationally designed by mixing hexadecyl trimethyl ammonium bromide(CTAB)-pillared organic montmorillonite with ZnSO4/MnSO4 solution (ZnOMMT). ZnOMMT can serve as the protective layer to alleviate Zn corrosion and MnO2 dissolution while the unique interlayer structure of ZnOMMT can also offer a selective pathway for fast Zn2+ transfer and uniform Zn2+ diffusion to inhibit the side-reaction and Zn dendrite generation. Notably, by the powerful pillaring of CTAB cations, the expanded and robust nanoscale interlayer tunnels of ZnOMMT for Zn2+ diffusion are constructed to guarantee outstanding ionic conductivity (6.52 mS cm−1), high Zn2+ transference number (t+=0.66) and outstanding cyclic stability during deep cycles. Therefore, ZIBs with ZnOMMT coating layer deliver a steady long-term reversible capacity (267 mAh g−1 until 300 cycles at 0.5 A g−1, 205 mAh g−1 until 700 cycles at 1.0 A g−1). The rational design of CTAB-pillared montmorillonite protective layer brings a brand-new opportunity to the realization of high-performance rechargeable ZIBs.