Covalent Anchoring of Mechanical Polymer for Highly Stable Zinc Metal Batteries

Artificial interfacial protective coatings (IPCs) on Zn anodes provide a viable solution for suppressing dendritic growth by spatially confining and homogenizing the Zn²⁺ flux. However, repeated Zn deformation during electroplating/stripping cycles can lead to the rupture or exfoliation of IPCs, as well as the formation of detrimental interfacial gaps. Herein, a highly durable IPC is developed on a Zn substrate using a mechanically robust fluorinated polyimide nanofilm (FPI). This unique FPI interphase forms strong covalent bonds with Zn through electronegative fluorine atoms, facilitating Zn plating/stripping while maintaining interfacial adhesion. The superior resilience, modulus, and low creep of the FPI film resist the impact stresses from electroplated Zn, ensuring structural integrity. With this FPI coating, the FPI-Cu||Zn half cells demonstrate high reversibility in Zn²⁺ electroplating/stripping over 4000 h, maintaining Coulombic efficiency above 99.33%. When coupled with a MnO₂ cathode, the MnO₂||FPI-Zn full cells exhibit a long lifespan, surpassing 5000 cycles, with a high specific capacity retention of 75.21%. This study highlights the importance of achieving a balance between the customized compatibility and mechanical properties of IPCs to modulate zinc interfacial chemistries.