Recent Advances in Mn‐Rich Layered Materials for Sodium‐Ion Batteries

Branded with low cost and a high degree of safety, with an ambitious aim of substituting lithium‐ion batteries in many fields, sodium‐ion batteries have received fervid attention in recent years after being dormant for decades. Layered materials are a major focus of study owing to the extensive experience already gained in lithium‐ion batteries, and the pursuit of a Mn‐rich composition is critical to reduce the cost while retaining the performance. This review provides a timely update of the recent progress of Mn‐rich layered materials for sodium‐ion batteries based on the understandings of the phase forming principles, structure transformation upon cycling and charge compensation mechanisms and discusses potential ambiguities in the pursuit of high‐performance materials.