Hydrated network interphase with dynamic negatively charged microregion enables ultra-stable aqueous zinc-ion batteries

Aiming at the critical bottleneck of interfacial instability of zinc anodes in aqueous zinc-ion batteries, the research group led by Houzhao Wan from Hubei University breaks the conventional thinking of "pre-fabricated polymer coatings" or "polymer electrolytes" and proposes a brand-new monomer-induced in-situ interface engineering strategy. The researchers innovatively introduce an appropriate amount of acrylamide (AM) monomers into ZnSO₄ electrolyte. Taking advantage of the preferential adsorption of AM on zinc surfaces, a hydrated network interphase (HNI) with dynamic negatively charged microregions (DNCM) is in-situ constructed on the zinc anode surface during electrochemical cycling under the synergistic triggering of Zn²⁺ and SO₄²⁻.

The HNI precisely regulates zinc deposition via a triple synergistic mechanism:
(1) Lewis acid-base coordination (C=O···Zn²⁺) provides fixed nucleation sites to guide oriented zinc deposition;
(2) Coulomb repulsion of DNCM homogenizes Zn²⁺ flux and eliminates concentration polarization;
(3) The dense hydrogen-bonding network restrains the activity of free water and suppresses hydrogen evolution reactions.

This strategy requires no additional initiators or crosslinkers. Only relying on the interfacial enrichment of intrinsic electrolyte ions under an electric field, spontaneous construction and dynamic regeneration of the interphase can be realized, which simultaneously possesses high ionic conductivity and outstanding interfacial wettability. Benefiting from the synergistic protection of this multifunctional interphase, zinc anodes deliver unprecedented cycling stability and reversibility, and the performance of full cells is significantly improved.

Highlights
1. In-situ construction and dynamic regulation: A monomer-induced in-situ interface engineering strategy is proposed. Relying on the preferential adsorption of acrylamide (AM) on Zn surface and synergistic triggering by Zn²⁺/SO₄²⁻ during electrochemical cycling, a stable hydrated network interphase (HNI) with dynamically distributed negatively charged microregions (DNCM) is in-situ built on the zinc anode, which realizes triple synergistic regulation of Zn²⁺ deposition.
2. Ultra-long lifespan and stable cycling: Benefiting from the multi-protective effect of HNI, the Zn//Zn symmetric cell delivers an ultra-long cycle lifespan of 8650 h (over 360 days) at 1 mA cm⁻² and stable cycling for 1600 h at 10 mA cm⁻². The Zn//Cu half-cell achieves an outstanding average Coulombic efficiency of 99.71%. The Zn//I₂ full cell retains 89.15% capacity after 12,000 cycles at 1 A g⁻¹, demonstrating remarkable electrochemical performance.

In summary, this paper proposes an in-situ interface engineering strategy based on acrylamide (AM) monomers. With the synergistic effect of electrochemically triggered Zn²⁺/SO₄²⁻ in ZnSO₄ electrolyte, a hydrated network interphase (HNI) with dynamic negatively charged microregions (DNCM) is in-situ constructed on the surface of zinc anodes. The HNI realizes precise regulation of zinc deposition behavior via a triple synergistic mechanism: Lewis acid-base coordination provides nucleation sites, Coulomb repulsion of DNCM homogenizes ion flux, and hydrogen-bonding networks suppress hydrogen evolution. Meanwhile, side reactions including dendrite growth, hydrogen evolution and corrosion are effectively restrained. This work not only offers a new paradigm for interfacial design of high-performance zinc anodes, but also provides strong support for the practical application of aqueous zinc-ion batteries.

Title:

Hydrated Network Interphase with Dynamic Negatively Charged Microregion Enables Ultra-Stable Aqueous Zinc-Ion Batteries

Journal Name: Nano-Micro Letters

DOI: https://doi.org/10.1007/s40820-026-02262-0

URL: https://scholarcast.cast.org.cn/top-news/2080136261242736640