Views: 0 Author: Site Editor Publish Time: 2026-06-29 Origin: Site
Aqueous zinc-ion batteries (AZIBs) have attracted attention for grid-scale energy storage due to their inherent safety and cost-effectiveness. However, their practical application faces three interconnected challenges that arise from high water activity and electrode interface instabilities:
Zinc dendrite growth — Inhomogeneous electric field distribution during zinc deposition leads to dendritic structures that can penetrate separators
Hydrogen evolution reaction (HER) — The more negative redox potential of Zn⊃2;⁺/Zn (−0.762 V vs SHE) compared to HER inevitably triggers hydrogen evolution, consuming protons and increasing local pH
Cathode degradation — In MnO₂-based cathodes, manganese dissolution during cycling leads to irreversible capacity loss
The pH Challenge
Interfacial pH plays a key role in zinc electrodeposition. In the mild acidic aqueous electrolyte (pH ≈ 4), HER inevitably occurs during cycling, increasing local OH⁻ concentration. When pH exceeds 5.47, the insulating byproduct Zn₄SO₄(OH)₆·xH₂O (ZHS) begins to form on the zinc surface. This high-surface-area byproduct creates a non-homogeneous zinc surface, continuously consumes Zn⊃2;⁺, and aggravates dendrite formation, leading to low Coulombic efficiency and short battery lifespan.
Existing Solutions: Progress and Limitations
Researchers have proposed various strategies, including artificial interface coatings, 3D hosts, alloying, and electrolyte engineering. Among these, adding trace additives to dilute aqueous electrolytes (e.g., 1-2 M ZnSO₄) is considered a promising strategy due to its facile process and cost-effectiveness. However, most reported additives are monofunctional —they can only protect the zinc anode from a single aspect. As a phosphate additive for zinc battery systems, ADP offers a distinct advantage over conventional single-function additives by addressing multiple failure modes simultaneously.
The performance of AZIBs with ADP additive described in this article is based on peer-reviewed research published in Journal of Materials Chemistry A (2026). Results were obtained under controlled laboratory conditions and may not directly translate to commercial-scale applications. Users should conduct independent validation for their specific systems.
Phosphate-based buffer additives have been studied in AZIBs for pH stabilization. Zhang et al. demonstrated that ammonium dihydrogen phosphate (NH₄H₂PO₄, NHP) can stabilize pH at around 2.8 through phosphate buffer pairs, effectively inhibiting side reactions and dendrite formation.
Compared to acetate-based buffer solutions, phosphate-based systems offer a broader pH buffer range and better buffering effect at specific pH values. Phosphoric acid undergoes more dissociation processes and has multiple buffer pairs: (H₂PO₄)⁻/(HPO₄)⊃2;⁻ (pKa=7.2) and H₂PO₄/(H₂PO₄)⁻ (pKa=2.1).
Comparison with Ammonium-Based Phosphate Additives: Ammonium dihydrogen phosphate (NHP) functions through NH₄⁺ electrostatic shielding and H₂PO₄⁻ pH buffering. However, its use involves a trade-off—the formation of ZHS comes at the cost of irreversible depletion of Zn⊃2;⁺ concentration. In contrast, ADP's Al⊃3;⁺ cation provides additional field-regulation benefits without the same Zn⊃2;⁺ depletion trade-off, as the Al-containing species participate in SEI formation rather than consuming Zn⊃2;⁺.
Recent research published in Journal of Materials Chemistry A (2026) demonstrates that ADP, functioning as a trace additive for aqueous zinc ion battery systems, constructs a robust “liquid-field-interface” triple-defense system through a cation-anion synergistic mechanism.
The ADP Triple-Defense System (Cation-Anion Synergistic Mechanism)
1. Bulk Electrolyte Regulation (H₂PO₄⁻ function): H₂PO₄⁻ anions from ADP reconstruct the Zn⊃2;⁺ solvation sheath, partially replacing water molecules. This suppresses free water activity and lowers the desolvation energy barrier at the electrode interface.
2. Interfacial Electric Field Regulation (Al⊃3;⁺ function): Al⊃3;⁺ cations preferentially adsorb onto high-field protrusions on the zinc anode surface—the locations where dendrites typically initiate. This creates a positive repulsive layer that homogenizes the Zn⊃2;⁺ flux, compresses the electric double layer, and boosts charge transfer kinetics.
3. Dual-Interface Protection (Synergistic effect): At the anode, ADP contributes to the in-situ formation of a Zn₃(PO₄)₂ solid-electrolyte interphase (SEI) that blocks water molecules from contacting the zinc surface. At the cathode, it mitigates manganese dissolution from the MnO₂ electrode.
Enabled by this multi-level regulation:
| Test System | Condition | Performance | ||
|---|---|---|---|---|
| Zn | Zn symmetric cells | 1 mA cm⁻⊃2;, 0.5 mAh cm⁻⊃2; | 6000 hours lifespan | |
| Zn | MnO₂ full cells | 1000 cycles | 94.1% capacity retention |
The performance data above represents optimized laboratory conditions. Actual results in commercial-scale systems may vary depending on cell design, operating conditions, formulation parameters, and purity of materials used.
Aluminum Dihydrogen Phosphate (ADP) is classified as an irritant. According to safety data sheets:
Hazard classification: Causes serious eye damage (H318); causes skin irritation (H315)
Required PPE: Safety goggles or face shield; chemical-resistant gloves (nitrile recommended)
First aid: In case of eye contact, rinse cautiously with water for several minutes; remove contact lenses if present; seek medical attention
Storage: Keep container tightly closed; store in dry, well-ventilated conditions; recommended storage temperature 15-25°C
Incompatibility: Aqueous solutions are incompatible with alkali and alkaline earth metals and many reactive organic and inorganic chemicals
Users must obtain and review the current Safety Data Sheet (SDS) before handling ADP. This article provides general information only and does not substitute for professional safety guidance.
Purity requirements: Battery applications may require higher purity grades than industrial-grade ADP (typically ≥93-95%) to avoid transition metal impurities that could affect cell performance
Laboratory to commercial gap: The reported 6000-hour performance was achieved under specific laboratory conditions; commercial validation is ongoing
System compatibility: ADP's effectiveness may vary with different cathode materials, current densities, and operating temperatures
Scalability: While ADP is commercially available at scale, battery-grade production may require additional purification steps
For energy storage system manufacturers, ADP offers a potential solution for improving aqueous zinc battery performance at trace-level addition concentrations that minimize material cost impact. For ADP suppliers, this represents an emerging application in the sustainable energy storage sector.
Areas warranting further research include:
ADP's effectiveness in other aqueous battery systems (e.g., Al-ion, Mg-ion batteries)
Long-term stability studies under practical operating conditions (elevated temperature, deep cycling)
Compatibility with other cathode materials
Q: What makes ADP different from other phosphate additives for AZIBs?
A: ADP uniquely combines H₂PO₄⁻ anions (for solvation regulation and pH buffering) and Al⊃3;⁺ cations (for interfacial field regulation) in a single compound, enabling cation-anion synergy.
Q: Is ADP commercially available in battery-grade quality?
A: ADP is commercially available from multiple suppliers. However, battery-grade purity requirements may vary. Users should verify specifications with their supplier for their specific application.
Q: Can ADP be used in other battery chemistries?
A: While the cited research focuses on AZIBs, the cation-anion synergy mechanism may be applicable to other aqueous battery systems. However, such applications require independent validation.
Q: What are the purity requirements for battery applications?
A: While research-grade ADP was used for the reported study, battery applications may require high-purity ADP (≥98-99%) to avoid transition metal impurities that could accelerate cathode degradation. Users should verify purity requirements for their specific system.
Q: Where can I find safety information for ADP?
A: Safety Data Sheets (SDS) are available from ADP suppliers and should be reviewed before handling.
For researchers and engineers seeking how to improve zinc battery cycling stability, the use of ADP as a trace additive for aqueous zinc ion battery systems offers a promising, cost-effective approach. Recent research published in Journal of Materials Chemistry A (2026) has demonstrated that Aluminum Dihydrogen Phosphate, at trace concentrations, can serve as an electrolyte additive for aqueous zinc-ion batteries through a cation-anion synergistic triple mechanism: (i) H₂PO₄⁻-mediated solvation regulation, (ii) Al⊃3;⁺-enabled interfacial field homogenization, and (iii) dual-interface protection at both anode and cathode.
The reported results include:
6000-hour lifespan in Zn||Zn symmetric cells
94.1% capacity retention after 1000 cycles in Zn||MnO₂ full cells
This represents a potential expansion of ADP's application landscape, from its traditional roles in high-temperature refractories, construction materials, and anti-corrosion coatings, into the field of sustainable energy storage.
Disclaimer: The information in this article is based on published academic research and is provided for informational purposes only. Performance claims are derived from laboratory studies and may not reflect commercial-scale results. Users should conduct their own testing and validation for their specific applications. Sherlock Chemical does not warrant the suitability of ADP for any particular application and assumes no liability for its use.
Sherlock Chemical supplies Aluminum Dihydrogen Phosphate (ADP) in both liquid and solid forms (CAS 13530-50-2).
Product Specifications (typical values) :
| Parameter | Liquid ADP | Solid ADP |
|---|---|---|
| Appearance | Colorless viscous liquid | White powder |
| P₂O₅ content | 40-45% | 80-85% |
| pH (20°C, 10g/L) | 1.5-3 | 2-4 |
| Density | 1.47 g/cm³ min | N/A |
Safety Notice: ADP causes serious eye damage and skin irritation. Wear protective gloves, eye/face protection when handling. Refer to Safety Data Sheet before use.
Contact us:
info@sherlockchemical.com
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Hao, M., Zhou, J., Deng, R., Qin, C., & Wu, F. (2026). Orchestrating dual-interface stabilization via a threefold mechanistic synergy of aluminum dihydrogen phosphate for ultrastable aqueous zinc-ion batteries. Journal of Materials Chemistry A, Accepted Manuscript. DOI: 10.1039/D6TA03126A
Zhang, W., Dai, Y., Chen, R., et al. (2022). Highly Reversible Zinc Metal Anode in a Dilute Aqueous Electrolyte Enabled by a pH Buffer Additive. Angewandte Chemie International Edition, e202212695
Liu, M., et al. (2024). Buffer solution additives for aqueous zinc-ion batteries. Energy Storage Materials, 67, 103248
Alfa Aesar. Aluminum dihydrogen phosphate, 50% w/w Aqueous Solution. Safety Data Sheet.
Carl Roth. Aluminum dihydrogen phosphate solution 50%, pure. Safety Data Sheet.
