Improving High-Voltage Cycling Stability and High-Rate Capability of Sodium-Ion Layered Cathode Oxides through Trace Amounts of Low-Valence Metals

With the increasing demand for clean energy sources, the need for large-scale energy storage systems to ensure the stable output of renewable energy sources, such as wind and solar, has also increased. Sodium-ion batteries have emerged as a potential solution for these storage systems owing to their high energy density, abundance in the Earth's crust, and low cost. However, the larger atomic radius of sodium ions results in higher energy barriers for ion migration in cathode materials, which can affect the cycle life and rate performance of the battery. Therefore, developing a suitable structure that facilitates rapid sodiation and desodiation and maintains good cycling stability remains a significant challenge. This study aimed to reduce the content of trivalent manganese ions and minimize the impact of the Jahn-Teller effect to enhance the capacity retention of manganese-based layered oxides. Additionally, a series of P2-type Na