Ultra-stable and deeply rechargeable zinc metal anode enabled by a multifunctional protective layer

Zinc metal is a promising anode material for aqueous energy storage devices with low cost and high safety. Nevertheless, the low Coulombic efficiency and unsatisfactory lifespan, arising from uncontrollable dendrites growth and side reactions, seriously hinders its commercial application. Herein, to overcome these limitations, a multi-functional protective layer (ZGL) which consists of zeolitic imidazolate framework (ZIF-8) decorated graphene oxide (GO) and PVDF is constructed to regulate the deposition behavior of Zn2 + on ultrathin Zn anode. The presence of ZGL can effectively seal the active Zn off from the electrolyte, thus minimizing side reactions. More impressively, the high binding energy between ZIF-8, GO and Zn, as reflected in electrochemical characterization, density functional theory calculation and in situ optical microscopy, endows ZGL with remarkable capturing capacity to Zn2+, ensuring dendrite-free Zn deposition. As a result, a record high cumulative capacity of 12000 mAh cm(-2) at 10 mA cm(-2), 85.5% depth of discharge (250 h), and excellent average Coulombic efficiency (99.6%) of 1450 cycles were achieved on well-designed Zn anode. When it is assembled with active carbon and MnO2 cathode, it delivers prominent cyclability of 13500 and 1200 cycles, respectively, indicating huge competitive advantage of our Zn ion battery and capacitor in practical applications.

Automated summary

In this study, a multi-functional protective layer was constructed to improve the performance of aqueous energy storage devices by regulating the deposition behavior of zinc, overcoming the limitations of uncontrollable dendrites growth and side reactions. The well-designed zinc anode achieved high Coulombic efficiency and long lifespan.