Ion‐Regulating SPEEK–BNNS Hybrid Interfaces Enabling Low‐Barrier Zn‐Ion Transport and Dendrite‐Free Zinc Anodes

Why It Matters

Stabilizing Zn metal anodes removes a major barrier to commercial aqueous Zn‑ion batteries, offering safer, lower‑cost energy storage compared with lithium systems.

Key Takeaways

• SPEEK‑BNNS layer combines mechanical strength and ion regulation
• SO3H groups lower Zn2+ adsorption energy and migration barrier
• Enables dendrite‑free Zn deposition over 1800 hours at 1 mA cm‑2
• Improves rate performance and capacity retention in Zn/MnO2 cells
• Scalable spray‑coating process compatible with existing battery manufacturing

Pulse Analysis

Aqueous zinc‑ion batteries promise high safety and low material cost, yet their commercial rollout stalls because zinc metal anodes rapidly develop dendrites and suffer parasitic side reactions in the aqueous electrolyte. These failures cause short circuits, capacity fade, and limited cycle life, making zinc‑based systems less reliable than their lithium counterparts. Researchers therefore focus on interfacial engineering to create protective layers that can both withstand mechanical stress and allow fast ion transport, a dual requirement that has proven difficult to achieve with single‑material coatings.

The newly reported hybrid coating merges sulfonated poly(ether ether ketone) (SPEEK) with boron nitride nanosheets (BNNS) via a spray‑coating technique that scales to industrial roll‑to‑roll processes. SPEEK’s –SO3H groups act as ion‑regulating sites, reducing Zn2+ adsorption energy and lowering migration barriers, as confirmed by density functional theory and nudged elastic band calculations. Meanwhile, BNNS contributes exceptional mechanical rigidity, distributing stress and physically blocking dendrite protrusion. The synergistic architecture yields uniform Zn2+ flux, enabling dendrite‑free plating for more than 1800 hours at practical current densities, and translates into higher rate capability and better capacity retention in Zn/MnO2 full cells.

Beyond laboratory performance, the hybrid’s manufacturability and material compatibility position it as a viable upgrade for existing zinc‑battery production lines. By addressing both electrochemical stability and mechanical durability, the SPEEK‑BNNS interface could accelerate the adoption of aqueous zinc‑ion batteries in grid‑scale storage, electric vehicles, and portable electronics. Future work may explore further functionalization of the polymer matrix or integration with other two‑dimensional nanomaterials to push energy density and lifespan even higher, cementing zinc’s role as a cornerstone of next‑generation sustainable energy storage.