Robust, High-Contrast, Recyclable Zinc-Based Dynamic Windows via Synergistic Electrolyte and Interfacial Engineering

TL;DR

This paper introduces a zinc-based electrochromic window with enhanced stability, high contrast, and recyclability achieved through electrolyte and interface engineering, enabling durable, multi-state optical modulation for energy-efficient buildings.

Contribution

It presents a novel synergistic electrolyte and interfacial engineering strategy that significantly improves the cycling stability and optical performance of zinc-based electrochromic devices.

Findings

Device achieves 15,000 cycle lifespan with negligible degradation.

Optical modulation exceeds 50% across multiple states.

Reflectance modulation remains stable over 2,000 cycles.

Abstract

Zinc-based electrochromic devices offer a sustainable route for dynamic optical management but are plagued by poor cycling stability due to irreversible zinc plating/stripping and side reactions. Herein, we report a robust, high-contrast, and recyclable zinc-based dynamic window enabled by a synergistic electrolyte and interfacial engineering strategy. Molecular dynamics simulations and electrochemical analyses reveal a dual-ion cooperative mechanism that governs the reversibility: anions with the strongest binding affinity guide uniform Zn deposition by stabilizing the inner solvation shell, while formate anions co-enriched at the interface facilitate smooth stripping via protonation during the oxidation process. This orchestrated interplay effectively eliminates "dead Zn" accumulation and dendrite growth. Consequently, the device demonstrates a record-high lifespan of 15,000 cycles with negligible degradation and maintains a large optical modulation of >50%, along with multiple optical states (transparent, gray, black, and mirror). Furthermore, it achieves a large reflectance modulation (>50%) stable for over 2,000 cycles. This work establishes the recyclable zinc-based dynamic window as a scalable, high-performance alternative to conventional electrochromic systems, advancing the feasibility of solution-processed energy-saving windows in sustainable buildings.