Research progress of manganese-based layered oxides as cathode materials for potassium-ion batteries

Abstract

In this paper, the research progress of K x MnO 2 as cathode material for potassium-ion batteries is reviewed, and a series of doping modification (low valence substitution) of this material is summarized. Finally, the future optimization measures of K x MnO 2 are proposed. • The research progress and challenges of monobasic K x MnO 2 as cathode materials for potassium-ion batteries are summarized. • The advantages of doped binary ferromanganese-based and manganese-magnesium-based materials as cathode materials for potassium-ion batteries are summarized. • The future improvement measures of K x MnO 2 material are proposed. Potassium is inexpensive, abundant, and evenly distributed in the Earth’s crust. It has similar physical and chemical properties to those of lithium. Therefore, the use of potassium-ion batteries is expected to be realized. Cathode materials are important components of potassium-ion batteries. In addition to potassium-containing compounds, other cathode materials should be actively explored. Manganese-based oxides are widely used as cathode materials in various batteries because of their multiple ion valence states, abundant mineral reserves, low cost, and convenient synthesis methods. Among these various cathode materials manganese dioxide with a layered structure has a large interlayer spacing, which can be used for the insertion and extraction of potassium ions with a large ionic radius between the layers. Therefore, layered K x MnO 2 (KMO) cathode materials have significant potential for development. This paper reviews the research status of manganese-, ferromanganese-, manganese magnesium-, nickel manganese-, nickel cobalt manganese-, and iron titanium manganese-based metal oxides as cathode materials for potassium-ion batteries. Additionally, the obstacles and opportunities faced by KMO materials as cathode materials for potassium-ion batteries are comprehensively discussed.