Electrode

Organic chemistry

Manganese oxide

Adsorption

Engineering

Valence (chemistry)

Physical chemistry

Desorption

Inorganic chemistry

Aqueous solution

Chemistry

Metallurgy

Materials science

Birnessite

Chemical engineering

Electrochemistry

Manganese

Oxygen

Delocalized electron

Advanced Energy Materials

A major limitation of MnO 2 in aqueous Zn/MnO 2 ion battery applications is the poor utilization of its electrochemical active surface area. Herein, it is shown that by generating oxygen vacancies ( V O ) in the MnO 2 lattice, Gibbs free energy of Zn 2+ adsorption in the vicinity of V O can be reduced to thermoneutral value (≈0.05 eV). This suggests that Zn 2+ adsorption/desorption process on oxygen‐deficient MnO 2 is more reversible as compared to pristine MnO 2 . In addition, because of the fact that fewer electrons are needed for ZnO bonding in oxygen‐deficient MnO 2 , more valence electrons can be contributed into the delocalized electron cloud of the material, which aids in enhancing the attainable capacity. As a result, the stable Zn/oxygen‐deficient MnO 2 battery is able to deliver one of the highest capacities of 345 mAh g −1 reported for a birnessite MnO 2 system. This excellent electrochemical performance suggests that generating oxygen vacancies in MnO 2 may aid in the future development of advanced cathodes for aqueous Zn ion batteries.

Defect Engineering of Oxygen‐Deficient Manganese Oxide to Achieve High‐Performing Aqueous Zinc Ion Battery