Superhydrophobic and robust hetero-metal-polymer hybrid interphase enables deep-cycling zinc metal anodes

Abstract

Realizing stable zinc (Zn) metal anodes under deep cycling conditions is the prerequisite for practical rechargeable Zn batteries but remains a significant challenge, due to severe water erosion and dendrite growth on Zn. Herein, a robust hetero-metal-polymer hybrid interphase composed of Pb nanoparticles embedded on the polyvinylidene difluoride (PVDF) matrix is in situ integrated on Zn anode by a one-step chemical displacement reaction to tackle these dilemmas. This concept can be readily extended to construct Bi-PVDF and Sn-PVDF hybrid interphases on Zn. Unlike the commonly developed hydrophilic and thick metal-based interphases, the superhydrophobic, thin, and seamless Pb-PVDF interphase, as a model example, can prevent water access to the Zn surface and exhibit an ultralow H2 evolution reaction potential, thus avoiding water-induced side reactions. Moreover, the flexible Pb-PVDF hybrid interphase with strong zincophilicity enables the dendrite-free and epitaxial Zn deposition. Consequently, the Pb-PVDF@Zn electrode manifests an ultralong lifespan over 8100 h (0.5 mAh cm-2 at 1 mA cm-2) and unprecedented deep cycling stability under 85.3% depth-of-discharge over 800 h (10 mAh cm-2 at 20 mA cm-2), which is 160-fold elongation of lifespan compared with bare Zn electrode. Moreover, the Pb-PVDF@Zn assures the stable operation of full Zn batteries with conventional V/Mn-oxide cathodes using both coin and pouch configurations.