Interlayer‐Engineered 1T‐MoSe 2 Enabling Reversible Mn 2+ /H + Hybrid Storage for Aqueous Manganese Batteries

Aqueous manganese batteries are emerging as safe, low‐cost options for large‐scale energy storage but are limited by sluggish Mn 2+ diffusion and poor reversibility. Here, we report an interlayer‐engineered 1T‐phase MoSe 2 cathode enabling fast, reversible hybrid storage of Mn 2+ and H + ions. Controlled chemical exfoliation induces a metallic phase transition and expands the interlayer spacing, creating a favorable environment for multivalent ion transport. The exfoliated MoSe 2 delivers 153.4 mAh g −1 at 0.1 A g −1 and retains 92.5% capacity after 1800 cycles. Kinetic analysis shows a reduced ion migration barrier compared with bulk MoSe 2 , highlighting the role of phase engineering and interlayer expansion. Spectroscopic and electrochemical analyses reveal a reversible Mn 2+ /H + co‐intercalation mechanism. A full cell paired with a Mn metal anode delivers 165.3 mAh g −1 and retains 89.9% of its capacity after 2000 cycles, demonstrating the practical feasibility of a rechargeable aqueous Mn‐metal battery. This work establishes phase‐engineered layered dichalcogenides as a platform for aqueous multivalent batteries and provides design principles to overcome kinetic limitations.