Rechargeable aqueous zinc-based batteries (AZBs) have emerged as a promising solution for large-scale energy storage due to their high safety, low cost, and environmentally friendly nature. The fundamental appeal of AZBs lies in the inherent advantages of metallic zinc: a high theoretical capacity of approximately 820 mAh g⁻¹ and a volumetric capacity of up to 5854 mAh cm⁻³. Additionally, zinc possesses a favorable standard redox potential of −0.76 V versus the standard hydrogen electrode (SHE), is chemically stable in air, and exhibits relatively low polarizability compared to other metals such as magnesium and aluminum. Its natural abundance further enhances its practical viability. Electrolytes commonly used in AZBs, such as ZnCl₂ and ZnSO₄, are inexpensive and widely available. Moreover, aqueous electrolytes generally exhibit significantly higher ion conductivity—about two orders of magnitude greater than organic electrolytes—contributing to excellent power density and fast charge-discharge kinetics.
Despite these compelling attributes, the widespread commercialization of AZBs remains hindered by their relatively low energy density. According to Equation (1), energy density (E) is directly proportional to both discharge capacity (Cₘ) and average output voltage (V):
E = Cₘ × V
This equation underscores that enhancing either capacity or voltage can substantially improve energy density.CLEC2 Antibody In stock While considerable research has been devoted to increasing specific capacity through novel cathode materials—such as layered V₂O₅, α-MoO₃, and α-MnO₂—recent efforts have increasingly focused on elevating the output voltage as a more effective pathway toward high-energy-density AZBs.
The primary limitation to achieving high output voltage in AZBs stems from the narrow electrochemical stability window (ESW) of aqueous electrolytes, which is typically around 1.23 V—the difference between the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). This constraint restricts the choice of suitable high-potential cathode materials. To overcome this, researchers have explored strategies involving electrode design, electrolyte engineering, and innovative battery architectures. One particularly effective approach involves constructing decoupled battery systems where the anodic and cathodic electrolytes operate under different pH conditions. By using an alkaline electrolyte at the anode and an acidic electrolyte at the cathode, the HER potential is lowered and the OER potential is raised, thereby expanding the ESW and enabling the use of high-redox-potential materials such as MnO₂/Mn²⁺ and PbO₂/PbSO₄.
In recent years, significant progress has been made in developing high-voltage AZBs through rational material design.AZI2 Antibody manufacturer For instance, incorporating crystal water into layered MnO₂ structures has been shown to reduce electrostatic interactions between Zn²⁺ ions and the host framework, facilitating faster ion diffusion and improving reversibility.PMID:35182729 Similarly, intercalation of large cations like La³⁺ or conductive polymers such as PEDOT into layered materials increases interlayer spacing and shields charge interactions, leading to enhanced voltage performance. Furthermore, tuning the electronic structure via metal doping—such as Co in V₂O₅—has been demonstrated to elevate the redox potential by modifying orbital hybridization and increasing Fermi level energy.
Another emerging strategy involves shifting the charge carrier from Zn²⁺ to lower-charge species like Li⁺, Na⁺, or H₃O⁺. These carriers exhibit faster diffusion kinetics and lower desolvation energy, allowing for higher operating voltages even within the limited ESW of aqueous systems. Hybrid zinc-ion batteries based on dual-electrolyte configurations or highly concentrated “water-in-salt” electrolytes (WISE) have successfully achieved output voltages exceeding 2.5 V, with some systems reaching up to 3 V when coupled with advanced membranes.
Nonetheless, several challenges remain. Structural degradation during cycling, especially in MnO₂-based cathodes, leads to irreversible phase transitions and poor cycling stability. Dendrite formation at the zinc anode continues to threaten long-term reliability. Moreover, the use of expensive ion-exchange membranes in decoupled systems raises cost concerns. Future research must focus on designing robust, scalable materials and electrolytes that maintain high voltage while ensuring durability, safety, and economic feasibility.
In conclusion, while AZBs face persistent hurdles related to energy density and cycle life, breakthroughs in electrode engineering, electrolyte formulation, and system architecture offer a clear path forward. With continued innovation, high-voltage rechargeable aqueous zinc-based batteries may soon become a cornerstone of sustainable energy storage infrastructure.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
