Hydrogen-bond chemistry inhibits Jahn-Teller distortion caused by Mn 3d orbitals for long-lifespan aqueous Zn//MnO₂ batteries

Manganese dioxide (MnO₂) is a promising cathode for aqueous Zn batteries owing to its high theoretical capacity and operating voltage. However, it is still confronted with poor conductivity, structural collapse, sluggish ion kinetics, and Jahn-Teller (J-T) distortion. Herein, we propose hydrogen bond-modulated MnO₂ by introducing NH₄⁺ (NHMO) for prominent zinc-ion storage. The formation of a hydrogen bond in MnO₂ reduces its layer spacing, presenting a more stable structure. The theoretical calculation results demonstrate that the pre-intercalation of NH₄⁺ can effectively reduce the bandgap of the MnO₂, enhancing its conductivity. More importantly, the formation of the hydrogen bond can significantly decrease the variation of Mn-O bond length and the proportion of Mn 3d_z² orbitals, meaning that the hydrogen-bond chemistry can effectively suppress J-T distortion. As expected, a high capacity of 287.9 mA h g⁻¹ at 0.1 A g⁻¹ and an ultrahigh rate performance (99.4 mA h g⁻¹ at 6.0 A g⁻¹) can be achieved for the NHMO, as well as a fantastically outstanding cycling stability of 90.0% after 13 000 cycles, far exceeding previously reported Mn-based materials. The rational introduction of a hydrogen bond provides a novel strategy for the development of ultralong lifespan aqueous Zn batteries.