Molecular bridging interface layer engineering for improved stability of Zn anodes

Abstract

To achieve commercial-grade lifespan and charge-discharge efficiency in aqueous zinc-ion batteries, a crucial prerequisite is establishing a robust and compatible electrode-electrolyte interface to mitigate the challenges posed by excessive dendrite proliferation and side reactions. Herein, we ingeniously engineer a durable interface layer on the zinc foil surface through an In-situ chemical grafting approach using silane as a molecular bridge (SG@Zn. This functionalized polysilane layer successfully welds the metallic substrate and the organic segments, fostering a highly compatible interface via robust Si-O-Zn bonds, serving as a shielding layer to protect the electrode from corrosion. The silane framework facilitates the uniform anchoring of subsequent zinc-affinitive functional groups at the molecular level, which not only brings a rapid zinc ion reaction kinetics but also ensures dual enhancement against expansion inhibition and dendrite penetration. Consequently, the symmetrical battery thus showcases superior reversibility in stripping/planting processes and demonstrates negligible voltage fluctuations at various currents and capacities. The MnO₂-based full batteries maintain a capacity of 200 mAh g ^-1 with a negligible cyclic capacity decay rate of 0.017% over 700 cycles at 1 C. This work offers a valuable perspective on interface engineering for high performance aqueous zinc-ion batteries.