Aqueous zinc-ion batteries use water-based electrolytes to transport charged particles between their electrodes. Unlike many lithium-based systems that rely on flammable organic solvents, water-based batteries carry a considerably lower fire risk and can potentially be manufactured from relatively abundant and inexpensive materials. These advantages have made them attractive for stationary energy-storage systems that collect electricity from renewable sources and release it when needed. Yet their practical performance has been limited by a fundamental trade-off: electrodes must accommodate enough ions to deliver high capacity while also allowing those ions to move rapidly during charging and discharging.

Zinc ions are appealing because each Zn²⁺ ion carries two units of positive charge, potentially contributing substantially to energy storage. However, their relatively large size and slower movement within an electrode can make it difficult to combine high capacity with fast operation. Protons, by comparison, are exceptionally small and can migrate through materials much more quickly. Their speed makes them attractive for rapid charge transfer, but protons have traditionally created serious problems in aqueous zinc-ion batteries. When they enter an electrode too early or in excessive numbers, they can trigger parasitic reactions and generate byproducts on the electrode surface. Those deposits can block pathways, disrupt zinc-ion transport, and gradually reduce battery performance.

Rather than suppressing proton activity, the KAIST team designed an electrode that controls when protons are allowed to participate. The material is a two-dimensional conductive metal–organic framework, or MOF, called Cu₃(HHTATP)₂. MOFs are porous crystalline structures assembled from metal centers and organic molecules, and their nanoscale channels can be chemically modified to influence how ions enter, move through, and bind within the material. In this case, the researchers introduced amine functional groups into the framework’s micropores. These chemical groups were designed to react with protons only after the electrode reached a specific voltage, effectively giving the material a built-in switching mechanism for sequential ion storage.

The result resembles filling a container with objects of different sizes. The electrode first stores the comparatively larger zinc ions while the battery operates in a higher-voltage range. As the voltage decreases, the amine groups become active and enable additional proton storage in the spaces and chemical environments that remain available. This order is crucial. If protons were admitted at the beginning of the process, they could generate surface byproducts before zinc ions had completed their storage step. By delaying proton participation, the electrode reduces competition between the two charge carriers and uses its porous architecture more efficiently.

Electrochemical measurements showed that zinc ions and protons contributed to energy storage in distinct voltage ranges. The research team used multiple X-ray analysis techniques to track the structural and chemical changes taking place inside the electrode, confirming that zinc ions were stored first and that protons entered afterward. The analyses also indicated that proton storage and release could be repeated, an important requirement for a rechargeable battery. Together, the results suggest that ion-storage sequence is not merely a side effect of electrode chemistry but can be deliberately engineered through molecular-level design.

The electrode achieved a storage capacity of 368.7 milliampere-hours per gram at a current density of 0.5 amperes per gram. Capacity expressed in milliampere-hours per gram indicates how much electrical charge can be stored per unit mass of active electrode material; a higher value means that a smaller quantity of material can hold more charge. The result is notable because aqueous zinc-ion batteries have often struggled to approach the combination of energy capacity and rapid ion transport associated with more established battery chemistries. By combining the charge contribution of zinc ions with the fast mobility of protons, the new material takes advantage of two different storage mechanisms within one electrode.

The material also retained 46.9 percent of its initial capacity when the charging and discharging rate was increased sixteenfold. Batteries commonly lose a significant portion of their storage capacity when operated rapidly because ions cannot move through the electrode quickly enough, and structural or chemical bottlenecks become more pronounced. Maintaining nearly half of the original capacity under such an accelerated condition suggests that the conductive two-dimensional framework and its controlled proton chemistry can support comparatively rapid electrochemical reactions. The electrode further maintained stable operation for more than 500 rapid charge–discharge cycles, indicating that the sequential process did not immediately destroy the material or permanently consume its proton-storage sites.

The study presents a broader design principle for battery research: ions that appear harmful under uncontrolled conditions may become useful when their reactions are separated in time and regulated by the molecular structure of an electrode. Professor Sarah S. Park, who led the KAIST research team, said that protons previously regarded as “troublemakers” could instead be used to store more energy, and that the principle might be applied to other electrode materials. The approach could be particularly relevant to large-scale energy-storage systems, where aqueous batteries offer safety and cost advantages but need higher energy density and faster response. The researchers now point toward the possibility of adapting sequential multi-ion storage to other porous conductive frameworks, potentially creating a new class of water-based batteries that combine rapid charging with greater energy storage.

Subject of Research: Sequential storage of zinc ions and protons in a conductive metal–organic framework for aqueous zinc-ion batteries.

Article Title: Sequential Zn²⁺–H⁺ Storage in a 2D Conductive Metal–Organic Framework for Advanced Aqueous Zinc-Ion Battery

Web References: https://doi.org/10.1016/j.chempr.2026.103129

References: Chem, DOI: 10.1016/j.chempr.2026.103129; article publication date: 7 July 2026.

Image Credits: KAIST

Keywords

Aqueous zinc-ion batteries, proton storage, zinc ions, metal–organic frameworks, conductive MOFs, Cu₃(HHTATP)₂, energy storage, fast charging, battery technology, sustainable batteries, large-scale energy storage, electrochemistry

Now, a comprehensive review in ENGINEERING Energy argues that atomic layer deposition (ALD) can directly address these bottlenecks by rethinking battery interfaces at the atomic scale. The authors emphasize ALD’s ability to produce sub-nanometer, highly conformal coatings on complex electrodes—an essential capability for protecting reactive components in aqueous environments.

Unlike conventional coatings that merely add physical separation, the review highlights a shift toward multifunctional interphases capable of actively regulating electrochemical reactions. This includes designing layers that suppress undesirable nucleation pathways, improve charge-transfer conditions, and steer zinc deposition to more stable regimes.

On the anode side, ALD can create uniform, pinhole-free protective films that limit direct contact between metallic zinc and electrolyte water. By reducing pathways for corrosion and hydrogen evolution (HER), these coatings also offer mechanical resistance to dendrite penetration, slowing the chain of failures that typically occurs after repeated plating/stripping.

Crucially, the review distinguishes passive barriers from chemically interactive, “zincophilic” layers such as ZnO, SnO₂, and Fe₂O₃. These materials can lower zinc nucleation overpotentials and promote preferential growth along specific crystallographic orientations, including the Zn (002) basal plane—an approach aimed at eliminating dendrites at their source rather than merely containing them.

The cathode is treated as another interface engineering frontier. High-capacity cathode chemistries based on vanadium- and manganese-containing oxides are vulnerable to dissolution and structural collapse. ALD coatings are presented as an “exoskeleton” that stabilizes active species and mitigates interfacial degradation while preserving electrochemical performance.

Beyond electrodes, ALD-enabled strategies extend to separators. The review discusses using metal-organic framework (MOF) materials, such as ZIF-8, to act as molecular sieves that promote selective Zn²⁺ transport while restricting bulky reactive species and free water. This structural regulation can reduce parasitic processes and extend cycle life.

Finally, the article confronts scalability. While ALD excels in precision, industrial adoption requires efficient deposition routes. The authors point to spatial ALD (S-ALD), roll-to-roll (R2R) ALD, and hybrid ALD/molecular layer deposition (MLD) approaches to balance performance with cost and manufacturability.

By mapping structure–property relationships from the atomic scale to full-cell behavior, the review offers a practical framework for designing durable, high-performance aqueous ZIBs. The message is clear: the path to grid-relevant zinc storage may depend less on new materials alone, and more on engineered interfaces that control chemistry, transport, and deposition dynamics simultaneously.

Subject of Research: Atomic layer deposition (ALD) for advanced zinc-ion batteries (ZIBs)
Article Title: Atomic layer deposition for advanced zinc-ion batteries
News Publication Date: 15-Jun-2026
Web References: https://doi.org/10.1007/s11708-026-1072-2
References: Huang, K., Zhang, S., Liu, Z. et al. Atomic layer deposition for advanced zinc-ion batteries. ENGINEERING Energy, 20, 10722 (2026). https://doi.org/10.1007/s11708-026-1072-2
Image Credits: Credit: Kaixin Huang, Shun Zhang, Zewen Liu, Tianzhu Zhang, Zongtao Lu, Bingsen Qin, Hongyao Wang, Zhenghao Li, Song Duan, Yun Zheng, Yinze Zuo, Wei Yan & Jiujun Zhang.

Keywords

Zinc-ion batteries; atomic layer deposition; interfacial engineering; dendrite suppression; corrosion and hydrogen evolution; zincophilic interphases; cathode stabilization; metal-organic frameworks (MOFs); spatial ALD; roll-to-roll ALD

At the heart of these challenges lies the process of zinc plating and stripping during battery charge and discharge cycles. Zinc anodes repeatedly undergo deposition and dissolution of metallic zinc, but this repeated action induces side reactions such as corrosion and the formation of zinc dendrites—needle-like structures that grow uncontrollably, piercing electrolyte separators and causing short circuits. Such phenomena severely degrade the cycling stability, lifespan, and overall reliability of aqueous zinc batteries, hampering their commercial viability despite their inherent safety advantages.

To tackle these fundamental issues, research has traditionally focused on engineering protective coatings designed to promote uniform zinc ion flux and suppress dendritic growth on the anode surface. While effective to an extent, conventional protective coatings often introduce new complications. Thick, dense films impede zinc ion transport, increasing ionic resistance and lowering battery performance. Moreover, manufacturing these protective layers tends to be costly and not easily scalable for larger electrode surfaces, limiting practical applications in commercial battery systems.

In an exciting development, a research group led by Associate Professor Woo-Jin Song at Chungnam National University in South Korea has introduced an innovative ultra-thin selective-ion transport layer (SITL) that addresses these limitations head-on. This groundbreaking work, published in the July 2025 edition of the Chemical Engineering Journal, unveils a nanoscale zinc-bonded polyacrylic acid (Zn–PAA) layer engineered for zinc anodes through a novel oxygen plasma treatment process. This approach capitalizes on the synergistic effects of polymer chemistry and surface engineering to produce an effective but incredibly thin ion-selective protective film.

What makes this Zn–PAA coating extraordinary is not only its remarkable thinness — at the nanoscale — but its facile and scalable fabrication method. The coating is applied to zinc anodes using a cost-effective spin-coating technique following oxygen plasma pretreatment, which fine-tunes the adhesion between the PAA polymer and the metallic zinc surface. This contrasts sharply with previous SITLs, which have suffered from complicated, multi-step, and bulky fabrication methodologies unsuitable for mass production on large electrode areas.

Mechanistically, the polyacrylic acid (PAA) component plays a crucial role in stabilizing the zinc anode. PAA’s hydrophilic nature enhances the interaction between the aqueous electrolyte and the zinc surface by promoting uniform ion transfer and distribution. Simultaneously, it forms a barrier that prevents the direct contact of the zinc metal with water, curbing corrosion and suppressing side reactions such as the hydrogen evolution reaction—a major source of irreversible capacity loss and electrolyte decomposition. Furthermore, the PAA protective layer considerably inhibits the formation of passivation layers originating from unwanted reactions with anionic electrolyte components that otherwise degrade the anode surface and exacerbate non-uniform zinc growth.

Yet, PAA alone suffers from solubility issues in aqueous environments, which traditionally undermines its protective functions during long-term cycling. The research team ingeniously addressed this problem by applying oxygen plasma treatment to the zinc anode prior to PAA deposition, a process that chemically modifies the zinc surface, increasing bonding sites and thus greatly enhancing the adhesion and stability of the PAA layer. Subsequent gentle heating induces the formation of zinc-bonded PAA (ZHP), a cross-linked, stable protective polymeric interface that resists dissolution even under harsh ultrasonic agitation in aqueous solutions, signaling robust mechanical and chemical resilience.

Electrochemical testing of the Zn@ZHP anodes revealed remarkable enhancements in cycling performance compared to bare zinc controls. The SITL effectively curtails dendritic growth during repeated plating and stripping processes, encouraging the deposition of uniform zinc crystals preferentially oriented along the (002) crystallographic plane. This crystalline orientation is known for its superior electrochemical activity, contributing to the observed improvements in performance. Impressively, symmetric cell configurations employing Zn@ZHP anodes sustained stable operation exceeding 2200 hours—significantly outlasting conventional zinc anodes under similar conditions.

More practically, full-cell zinc-ion batteries incorporating the ZHP-coated anodes sustained 95% of their initial capacity even after 500 charge-discharge cycles at a current density of 1 A g⁻¹. This level of stability at commercially relevant current rates is a compelling indicator of the technology’s readiness for real-world applications. Extending beyond laboratory-scale coin cells, the team also demonstrated pouch-cell configurations that maintained stable cycling for over 300 cycles under a demanding current density of 10 mA cm⁻², spotlighting the scalability and robustness of the approach.

Dr. Song underscores the broader implications of this advancement: “The enhanced stability of water-based electrolytes makes ZHP-based ZIBs ideal for safety-critical industries such as grid-scale energy storage systems and detection sensors. Furthermore, their low cost and toxicity render these batteries promising candidates for portable electronics and wearable devices.” This multifaceted applicability—from large energy storage grids requiring safe, cost-effective solutions to compact consumer electronics demanding reliability—makes the Zn–PAA nanolayer innovation a pivotal breakthrough.

This innovative protective polymer layer effectively bridges a long-standing gap in aqueous zinc battery research. By harmoniously balancing the need for uniform zinc ion transport, corrosion inhibition, side reaction mitigation, and practical manufacturability, this study paves the way for zinc-ion batteries to transition from niche laboratory curiosities to commercially viable, next-generation energy storage solutions. Given the ever-increasing demand for safe, affordable, and sustainable battery technologies, this pioneering work undoubtedly marks a major milestone.

The synergy of polymer chemistry, surface modification, and scalable engineering highlighted in this research resonates across the broader landscape of energy storage material science. It not only advances the zinc-ion battery domain but offers a blueprint for future innovations aiming to reconcile performance with manufacturability in emerging battery technologies. As demand intensifies for batteries that are safer and environmentally benign, the Zn–PAA nanoscale SITL represents a promising stride toward sustainable, high-performance alternatives capable of redefining how we store and deploy energy in the years to come.

Subject of Research: Not applicable

Article Title: Development of artificial zincophilic polymeric nanolayers on zinc anodes for high-performance zinc batteries

News Publication Date: 1-Jul-2025

Web References: https://doi.org/10.1016/j.cej.2025.162948

References: DOI: 10.1016/j.cej.2025.162948

Keywords

Batteries, Nanotechnology, Energy storage, Materials science, Electrochemistry, Chemical engineering, Electronics, Renewable energy, Biotechnology, Anodes

The conventional energy storage systems we rely on today have several limitations, primarily concerning efficiency and sustainability. With the growing demand for cleaner energy solutions, zinc-ion batteries (ZIBs) have emerged as a promising alternative due to their inherent safety features and environmental benefits. However, the commercial viability of ZIBs has been hampered by insufficient electrode materials that can efficiently conduct ions while maintaining structural integrity during charge-discharge cycles. This is where the new V₂O₅-coated graphite felt composite comes into play.

Graphite felt, known for its excellent electrical conductivity and mechanical strength, serves as a robust substrate in this composite cathode. By coating it with vanadium pentoxide (V₂O₅), researchers have harnessed the advantageous properties of both materials, creating a system that not only enhances ion mobility but also boosts the overall capacity of the electrode. V₂O₅ plays a crucial role in facilitating the electrochemical reactions necessary for zinc-ion transfer, thereby contributing to a more efficient charging and discharging process.

The synthesis process of this composite is equally fascinating and highlights the meticulous nature of material science in battery development. The researchers employed a methodical approach to ensure that the V₂O₅ is uniformly distributed over the graphite felt substrate. This uniform coating is essential for maximizing the active surface area available for electrochemical reactions, directly impacting the efficiency and energy density of the resulting cathode. The innovative techniques used in synthesizing this composite reflect a new era of battery technology, where precision and control can lead to groundbreaking advancements.

In terms of performance metrics, preliminary tests have showcased the exceptional capabilities of the V₂O₅-coated graphite felt composite cathode. The impedance measurements of the battery system indicate a significant decrease in resistance, which correlates with faster charge and discharge rates. Furthermore, the cycling stability of the cathode has surpassed that of traditional materials, demonstrating the potential for long-term use in practical applications. Such advancements in performance are poised to revolutionize how we consider and utilize energy storage technologies.

Moreover, the environmental implications of this research cannot be overstated. Zinc is a widely abundant and non-toxic element, making zinc-ion batteries a more sustainable choice compared to lithium-ion counterparts. By optimizing the cathode materials, the researchers have not only paved the way for more effective energy storage solutions but have also taken significant steps towards reducing the ecological footprint associated with battery production and disposal. This aligns with global efforts to transition towards a greener and more sustainable future.

The impacts of this research extend beyond just the performance of zinc-ion batteries. The methodologies developed for synthesizing the V₂O₅-coated graphite felt composite may inspire the exploration of other combinations of materials and layering techniques. The framework established by Liu et al. demonstrates that with the right combination of materials and processes, it is possible to harness untapped potentials within existing substances, leading to innovative solutions in the energy sector.

As we look forward, the adoption of these advanced materials in commercial applications will require collaboration between academic researchers and industry leaders. The scalability of this synthesis method will play a critical role in determining how quickly these advancements can be translated into real-world solutions. Industry partnerships can aid in the fine-tuning of production techniques, allowing for the rapid deployment of this technology in markets that prioritize renewable energy and efficient storage systems.

The scholarly article detailing this research is anticipated to evoke significant interest in the scientific community, continuing the dialogue on sustainable energy storage solutions. By introducing this innovative V₂O₅-coated graphite felt composite cathode, the authors have not only contributed to our understanding of zinc-ion batteries but have also inspired future studies aimed at further improving battery technologies. Other researchers in this field will undoubtedly look to replicate and expand upon these findings, driving the evolution of energy storage systems forward.

Prominent journals and publications are likely to feature this work, emphasizing the importance of interdisciplinary collaboration in tackling complex challenges faced by contemporary society. Teams composed of chemists, materials scientists, and engineers will benefit from the insights shared in this study, allowing for a broad spectrum of investigative approaches in the pursuit of groundbreaking technologies that challenge the status quo.

In summary, the synthesis of the V₂O₅-coated graphite felt composite cathode represents a pivotal moment in the realm of zinc-ion batteries, showcasing the innovative spirit of researchers committed to providing efficient and sustainable energy solutions. As this work progresses from the laboratory to practical applications, the implications for energy storage systems across various domains stand to alter our technological landscape profoundly. Researchers remain hopeful that such innovations will inspire a new wave of sustainable practices in energy storage, ultimately leading us towards a greener and more energy-efficient future.

Subject of Research: Development of a self-supported V₂O₅-coated graphite felt composite cathode for zinc-ion batteries

Article Title: Synthesis of self-supported V₂O₅-coated graphite felt composite cathode for high-performance zinc-ion batteries

Article References: Liu, Z., Li, J., Wen, H. et al. Synthesis of self-supported V₂O₅-coated graphite felt composite cathode for high-performance zinc-ion batteries. Ionics (2025). https://doi.org/10.1007/s11581-025-06556-y

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s11581-025-06556-y

Keywords: Zinc-ion batteries, V₂O₅ coating, graphite felt, self-supported cathode, energy storage solutions, sustainable materials, electrochemical performance, battery technology.