Hydrogen evolution reaction-resistant manganese-telluride anodes for aqueous manganese-ion batteries

Aqueous manganese (Mn)-ion batteries are attractive for safe and low-cost energy storage, but metallic Mn anodes suffer from severe corrosion and hydrogen evolution. Here, we introduce manganese telluride (MnTe) as an alternative Mn-based anode that stabilizes Mn redox chemistry through Te alloying. Unlike metallic Mn, MnTe suppresses spontaneous hydrogen evolution and enables reversible Mn extraction and reinsertion through a phase-mediated pathway involving MnTe, MnTe₂, and Te. This distinct reaction mechanism markedly improves electrochemical stability. MnTe symmetric cells operate for over 450 h with low polarization, and asymmetric cells achieve a high Coulombic efficiency of 97.49%. When paired with a pyrene-4,5,9,10-tetraone cathode, MnTe full cells operate within an aqueous voltage window up to 1.5 V and retain ≈70 mAh g^-1 after 100 cycles at 1C, outperforming pristine Mn and Zn powder anodes under matched powder-electrode conditions. These results establish alloy-mediated Mn redox regulation as an effective strategy for aqueous battery anodes.