Aqueous manganese-ion batteries (AMIBs) are emerging as promising candidates for large-scale, safe, and low-cost energy storage owing to the natural abundance and much lower redox potential of manganese compared with zinc. Here, we realize a high-voltage AMIB by pairing a semi-crystalline, porous polyaniline (PANI) cathode with a Mn metal anode. Exploiting the intrinsically lower Mn potential (-1.19 V vs. SHE) than Zn (-0.76 V) enables an average cell voltage of 1.27 V-over 30% higher than conventional Zn-based aqueous batteries-while keeping PANI within its stable electrochemical window. The PANI cathode delivers a high reversible capacity of 88.3 mAh/g and retains 67.9% capacity after 1000 cycles, with ex situ spectroscopy revealing a highly reversible Mn² ⁺/H⁺ hybrid storage mechanism and exceptional structural stability. Full Mn//PANI cells markedly outperform Zn analogues not only in voltage but also in rate capability and cycle life, maintaining 81.3% capacity after 500 cycles at 1.0 A/g. These findings position PANI as a high-performance organic cathode and establish clear system-level advantages of Mn over Zn for next-generation high-voltage aqueous batteries.

Tunnel-type cobalt vanadate dihydrate (Co(VO₃)₂·2H₂O, CoVO) is first demonstrated as a robust cathode for aqueous Zn-ion batteries. The orthorhombic framework, built from CoO₆ octahedra and VO₄ tetrahedra, incorporates two structural water molecules directly coordinated to Co²⁺. These structural waters serve critical functions: 1) forming hydrogen-bond networks that buffer local strain, 2) shielding electrostatic repulsion between Zn²⁺ and the polyanionic framework, and 3) creating secondary diffusion channels that accelerate H⁺/Zn²⁺ transport. Owing to this cooperative effect, CoVO delivers 83.6 mAh/g at 0.5C and retains 90.6% capacity after 1000 cycles at 3C. Ex situ XRD and Rietveld refinements confirm a topotactic, zero-strain intercalation mechanism (ΔV = 0.17%) without bulk decomposition, while bond valence sum analysis reveals dual-ion pathways with low migration barriers. The synergy between tunnel topology and structural water coordination underpins the exceptional rate capability, minimal impedance growth, and long-term stability, establishing a general design strategy for advanced multivalent-ion battery cathodes.

Aqueous batteries have garnered considerable attention because of their cost-effectiveness, sufficient capacity, and non-flammable water-based electrolytes. Among these, manganese batteries are particularly attractive owing to their stability, abundance, affordability, and higher energy density. With a lower redox potential (Mn: -1.19 V vs SHE) than zinc (Zn: -0.76 V vs SHE), manganese batteries theoretically offer superior energy density over traditional zinc-based systems. In this study, LiFePO₄ is introduced as a cathode material in aqueous manganese-based hybrid batteries for the first time. Through electrochemical characterization and advanced structural and spectroscopic analyses, the charge storage mechanisms of protons in to the FePO₄ are elucidated. Cation diffusion pathways are also investigated via diffusion barrier calculations. This study presents manganese hybrid batteries with a good stability and capacity of ≈109.2 mAh g^-1 at 40 mA g^-1, alongside a cycle retention of 42.1% after 3000 cycles at 320 mA g^-1. Furthermore, an Mn²⁺/Li⁺ hybrid battery, achieving ≈1.6 V and superior durability (81.5% @ 1000th), is proposed.

Aqueous rechargeable metal batteries have gained significant attention because of the low cost, high capacity, and inherent safety offered by nonflammable water-based electrolytes. Among these, Mn-based systems are promising owing to their intrinsic stability, abundance, affordability, and high energy density. Despite these advantages, the development of suitable host structures for Mn storage remains underexplored. This study introduces layered iron vanadate, FeV₃O₉·1.1H₂O, as a new cathode material for aqueous Mn batteries, demonstrating exceptional performance. The cathode exhibits a reversible capacity of 306.9 mAh g^-1 at 0.25 A g^-1 and an excellent rate performance of 210.6 mAh g^-1 at 2 A g^-1. In addition, FeV₃O₉·1.1H₂O exhibits outstanding cycling stability, retaining 73.4% of its initial capacity after 3000 cycles at 3 A g^-¹, which is attributed to its low layered volume expansion. The underlying reaction mechanism is elucidated through spectroscopic and microscopic analyses. When integrated into the final Mn cell, the cathode system demonstrates superior performance compared to Zn batteries, underscoring its potential for next-generation aqueous battery systems. These findings advance the aqueous Mn battery technology, paving the way for safer, more cost-effective, and high-performance energy storage solutions.

Lithium-Metal Batteries A triple-layered, noncombustible PEO-based solid electrolyte incorporating DBDPE and Zeolite Beta is demonstrated for use in highly safe lithium-metal batteries. The electrode-contacting layer employs a highly concentrated LiTFSI solid polymer electrolyte to enhance electrode compatibility, facilitate the free movement of Li cations, and improve Li-ion conductivity. More in article number 2406200, Jae Hyun Kim and co-workers.

Manganese-based ion batteries exhibit a relatively low redox potential (-1.19 V vs SHE) along with high theoretical capacity and excellent capacity retention characteristics, making them promising for next-generation batteries. In this study, a high-performance manganese hybrid aqueous battery with an expanded interlayer spacing is designed and fabricated using MgV₆O₁₆·7H₂O (MgVO) as the cathode material and manganese metal as the anode. The fabricated Mn metal battery achieves an initial discharge capacity of 195.3 mAh g^-1 (with Mn metal anode) at a current density of 0.1 A g^-1 with 1.19 V and exhibits excellent capacity retention of even after 200 cycles at a current density of 0.4 A g^-1. Furthermore, detailed structural behavior and operational mechanisms of ions within the MgVO electrode are elucidated through comprehensive analyses of the crystal structure, ion diffusion pathways, and activation energy calculations. Compared to zinc-based aqueous batteries (-0.76 V vs SHE), the manganese-based system demonstrates a ≈0.43 V higher theoretical operating voltage, which is consistent with the experimental observations. This study not only confirms the potential of MgVO as a promising cathode material for next-generation manganese aqueous batteries but also provides valuable insights for the performance enhancement and design optimization of manganese-based aqueous battery systems.