The pursuit of high-voltage operation in aqueous zinc-based batteries (AZBs) has become a central focus in advancing their energy density and practical applicability. While AZBs inherently offer advantages such as safety, low cost, and environmental sustainability, their output voltage is fundamentally constrained by the narrow electrochemical stability window (ESW) of water—approximately 1.23 V—dictated by the thermodynamic limits of hydrogen and oxygen evolution reactions. This limitation restricts the selection of suitable cathode materials and caps the achievable voltage below 2 V in conventional systems. To overcome this bottleneck, researchers have developed multifaceted strategies that span electrode material engineering, electrolyte optimization, and innovative battery system design.
One effective approach lies in selecting cathode materials with intrinsically high redox potentials. Materials such as Prussian blue analogues (PBAs), MnO₂, and certain organic carbonyl compounds have demonstrated promising performance due to their ability to operate at elevated voltages. For example, PBAs can deliver an average voltage of up to 1.7 V vs. Zn/Zn²⁺ despite modest capacity, resulting in competitive energy densities. Similarly, manganese dioxide (MnO₂) exhibits high potential in acidic environments, where the Mn⁴⁺/Mn²⁺ redox couple operates at around 1.228 V vs. SHE, enabling higher cell voltages compared to alkaline conditions. Recent studies have also explored iodine-based cathodes and conductive polymers like polyaniline, which show favorable redox behavior and tunable voltage profiles through chemical functionalization.
Beyond material selection, modifying the intrinsic properties of cathode materials has proven instrumental in boosting voltage. Crystal structure engineering plays a crucial role: intercalating species such as water molecules, alkali metal ions (e.g., Li⁺, Na⁺), or large cations like La³⁺ into layered or tunnel-structured oxides increases interlayer spacing and reduces Coulombic repulsion between Zn²⁺ and the host lattice. This facilitates faster ion transport and enhances reversibility. For instance, crystal water insertion into -MnO₂ has been shown to increase the discharge voltage from ~1.4 V to over 1.55 V. In another study, PEDOT-intercalated NH₄V₃O₈·0.5H₂O exhibited a flat voltage plateau of 1.0 V vs. Zn/Zn²⁺, significantly higher than the pristine NVO counterpart (0.9 V).
Electronic structure modulation via defect engineering and heteroatom doping further enhances electrochemical performance. Introducing Co into V₂O₅, for example, strengthens the interaction between Co 3d and V 3d orbitals, raising the V⁵⁺/V⁴⁺ redox potential and enabling a high-voltage output above 1.0 V. Similarly, incorporating Co into Prussian blue frameworks activates additional Co³⁺/Co²⁺ redox couples, increasing overall voltage. Oxygen redox activity in vanadium phosphates (VOP₄) has also been leveraged, where lattice oxygen participates in charge compensation during high-voltage charging, pushing the operating voltage to approximately 1.56 V.
An alternative paradigm involves changing the dominant charge carrier from Zn²⁺ to lower-charge species such as Li⁺, Na⁺, or H₃O⁺. These carriers possess smaller ionic radii and lower desolvation energy, leading to faster reaction kinetics and reduced polarization. Hybrid zinc-ion batteries utilizing lithium-ion cathodes—such as LiVPO₄F—paired with concentrated dual-ion electrolytes have achieved output voltages exceeding 1.P27 Kip1 Antibody MedChemExpress 8 V.CD3D Antibody In Vivo The use of highly concentrated “water-in-salt” electrolytes (WISE) not only widens the ESW to nearly 3 V but also suppresses water decomposition, enabling stable operation of high-potential redox couples.PMID:34156757
Perhaps the most transformative strategy is the design of decoupled battery systems. By separating the anodic and cathodic compartments with a selective ion-exchange membrane and employing different electrolytes—alkaline at the anode and acidic at the cathode—the ESW can be effectively expanded beyond 2 V. This allows the use of high-redox-potential cathodes like MnO₂/Mn²⁺ or PbO₂/PbSO₄ while maintaining a low-potential zinc anode. In one notable example, a decoupled Zn//MnO₂ battery achieved a voltage of up to 2.5 V with near-theoretical capacity (~616 mAh g⁻¹) and excellent Coulombic efficiency. Another system using Ni-doped MnO₂ enabled ultraflat discharge curves and fast kinetics even at 50 C, highlighting the potential of this architecture for high-power applications.
Despite these advances, challenges remain. Structural instability, side reactions, dendrite formation, and the high cost of membranes limit long-term cyclability and commercial viability. Future research must prioritize scalable fabrication methods, durable interface engineering, and cost-effective membrane alternatives. Ultimately, integrating rational electrode design with advanced electrolyte and system-level innovations will be key to unlocking the full potential of high-voltage aqueous zinc-based batteries for next-generation energy storage.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
