Sankhadip Saha

Abstract Manganese dioxide (MnO2) is a leading positive electrode candidate for aqueous zinc-ion batteries, combining safety, high voltage, low cost, and sustainability for grid-scale storage. However, its practical development remains restricted by poor reversibility, rooted in an unresolved mechanistic debate spanning over a decade.

1 Introduction Traditionally, with the concept of phase engineering, researchers have targeted specific crystal phases of a material to tune and understand catalytic performance [1, 2]. In areas of materials science and engineering, it is well understood that the properties of the material are governed and can be enhanced by the grain boundaries of again typically pure crystal phases.

1 Introduction Heterogeneous photocatalysis strives to harness sunlight and convert it into chemical energy.[1] This process seeks to replicate natural photosynthesis, where plants convert sunlight into chemical energy. The field has traditionally relied on semiconductors to drive chemical reactions.[2] When these semiconductors are exposed to light with energy greater than their band-gap, they absorb the light and create electron-hole pairs.