Promoting Proton Transport in Si‐Doped α‐MoO ₃ via Bond‐Weakening Engineering for High‐Rate and Long‐Life Aqueous Proton Batteries

ABSTRACT Aqueous proton batteries (APBs) hold promise for high‐rate energy storage, but their development is hindered by the instability of α‐MoO ₃ electrodes, which suffer from dissolution and hydrogen evolution reactions. Herein, we report a bond‐weakening engineering strategy via Si doping to boost proton transport in α‐MoO ₃ . The introduced Si(IV) forms Mo–O─Si linkages, reducing electron density around oxygen and weakening O─H bonds, thereby facilitating proton desorption and migration. The optimized Mo _0.8 Si _0.2 O _3−x electrode achieves a high specific capacity of 223.03 mAh g ⁻¹ at 1 A g ⁻¹ and retains 63.57% capacity at 20 A g ⁻¹ , vastly outperforming pristine α‐MoO ₃ . In a full cell with a vanadium hexacyanoferrate (VHCF) cathode, the Mo _0.8 Si _0.2 O _3−x anode exhibits exceptional cycling durability (91.87% capacity retention after 4000 cycles at 8 A g ⁻¹ ). Density functional theory calculations confirm a reduced bandgap and lower proton diffusion barrier, underscoring the potential of non‐metal doping for high‐rate proton batteries.