Differentiated Adsorption Modulation of Microdose Additive Enhances Stability and Kinetics in Zinc‐Ion Batteries

Why It Matters

By delivering both long‑term cycling stability and high rate performance, the PD additive makes aqueous zinc‑ion batteries more viable for grid‑scale storage, where safety, cost, and durability are critical.

Key Takeaways

• Polydextrose additive at 0.01 M improves Zn anode stability.
• Zn||Zn cells run >2100 h at 2 mA cm⁻² with PD.
• Full cells retain 81% capacity after 1300 cycles.
• PD adsorbs zincophilically yet stays Zn²⁺‑phobic in bulk.
• Strategy resolves stability‑kinetics trade‑off for aqueous Zn batteries.

Pulse Analysis

Aqueous zinc‑ion batteries (AZIBs) have attracted attention as low‑cost, safe alternatives for stationary energy storage, yet their commercial rollout stalls because the zinc metal anode suffers from dendrite growth, hydrogen evolution, and corrosion. Conventional electrolyte formulations either protect the metal surface or maintain fast ion transport, but rarely both, forcing designers to compromise between cycle life and power capability. Recent research therefore focuses on additives that can selectively modify the electrode–electrolyte interface without degrading bulk conductivity.

The study leverages polydextrose, a cheap, biomass‑derived polymer, at a microdose of 0.01 M to create an "adsorption‑differential" environment. At the anode, PD’s hydroxyl groups bind zincophilically, reconstructing the surface and guiding Zn²⁺ deposition onto the (002) crystallographic plane, which curtails dendrite nucleation. Simultaneously, PD remains Zn²⁺‑phobic in the surrounding electrolyte, preserving the native Zn(H₂O)₆²⁺ solvation shell and the high ionic conductivity of ZnSO₄ solutions. This dual action eliminates the usual trade‑off, delivering over 2,100 hours of stable cycling at 2 mA cm⁻² and impressive capacity retention in full cells.

For the energy‑storage industry, the findings offer a scalable, cost‑effective pathway to enhance AZIB performance without redesigning cell architecture. Polydextrose is already produced at industrial scale for food applications, suggesting minimal supply‑chain hurdles. The additive’s simplicity could accelerate pilot projects and large‑scale deployments, especially in regions seeking safe, inexpensive storage for renewable integration. Future work may explore synergistic blends with other polymers or electrolytes, but the core principle—differential adsorption to decouple interfacial protection from bulk transport—sets a new design paradigm for next‑generation aqueous batteries.