Suppressed Dissolution and Enhanced Desolvation in Core–Shell MoO 3 @TiO 2 Nanorods as a High‐Rate and Long‐Life Anode Material for Proton Batteries

Abstract Rechargeable proton batteries are attractive, because protons as a charge carrier have a small ionic radius, a lightest mass, and a high abundance on Earth. MoO 3 , as one of the promising anode materials in rechargeable proton batteries, suffers from the severe dissolution in acidic electrolytes upon cycling. Here, an ultrathin TiO 2 shell is coated on MoO 3 nanorods to suppress the detrimental dissolution during cycles. TiO 2 also lowers the desolvation energy of hydrated protons, promoting the reaction kinetics. As a result, MoO 3 @TiO 2 displays outstanding electrochemical performance, especially at high rates (171.0 mAh g −1 at 30 A g −1 ) and at high mass loadings (17 mAh cm −2 at 104 mg cm −2 ). The full cells constructed with MnO 2 deliver an energy density up to 252.9 Wh kg −1 and a power density of 18.3 kW kg −1 . Ex situ X‐ray diffraction and X‐ray photoelectron spectroscopy indicate that protons shuttle back and forth between different monoclinic phases. The results offer a simple way to achieve the high performance of MoO 3 in a diluted acidic solution.