Preparation of an organic-copper composite modified layer via displacement reaction on zinc anode.

Aqueous zinc-ion batteries face severe challenges in practical cycling, mainly including irregular zinc dendrite growth and unstable interfacial reactions, which greatly degrade the cycling performance. Herein, via a facile immersion method relying on a one-step in-situ spontaneous displacement reaction, an organic-inorganic composite layer composed of organic components and copper nanoparticles are fabricated on the surface of the zinc metal anode. The upper layer is enriched with carboxyl groups and Cu2+, constructing the upper layer by coordination interactions. Acting as migration sites and transport pathways for Zn2+, the as-formed SEI layer induces the uniform and ordered deposition of zinc. The bottom layer is composed of zincophilic copper clusters, which can form a compact physical shielding layer on the zinc anode surface and effectively inhibit interfacial corrosion. Benefiting from the synergistic effect, the symmetric cell achieves an ultra-long cycle life of over 4000 h at 3 mA cm-2, and still maintains a cycle life exceeding 2000 h even at a high current density of 10 mA cm-2. Meanwhile, the Cu-BTC@Zn//MVO full battery exhibits a 57% increase in capacity retention compared with bare Zn anode after 700 cycles. Meanwhile, this work reveals the synergistic regulation mechanism of the organic-inorganic composite layer toward Zn deposition, and provides a facile and practical strategy to construct stable artificial SEI layers for high performance zinc-metal anodes.