Interlayer Ag+ and In Situ Ag Metal Particles Synergistically Strengthening MnO2 Cathode Performance for Aqueous Zinc-Ion Batteries

Abstract

Layered manganese oxide has rich active sites, amounts of variable valence states, and economic feasibility, so it has attracted wide attention. In aqueous zinc ion batteries, its poor conductivity and easy solubility in water limit its performance as an electrode. Therefore, we used a simple one-step hydrothermal method to prepare Ag+ intercalated MnO2 for aqueous zinc-ion batteries’ cathode. An in-depth exploration of the electrochemical phenomenon of Ag–MnO2 found that interlayer Ag+ regulates the electronic structure of MnO2 and reduces the Jahn–Teller effect, and the desolvation of Ag–MnO2 is easier, which promotes the embedding of Zn2+. In addition, the migration of Ag+ and the in situ formation of Ag metal particles also enhance the conductivity of the electrode. As a result of the Ag+-Ag0 synergistic effect, Ag–MnO2 has obtained high rate performance (275.6 mA·h·g–1 at 200 mA·g–1) and excellent cycle stability (98.8% capacity retention over 600 cycles at 1000 mA·g–1). This provides insights for the pre-inserted Ag+ to improve the electrochemical performance of MnO2.