# High Entropy Layered Cathode With Single Grain Morphology for High‐Performance Sodium‐Ion Batteries

## TL;DR

This paper introduces a new high-entropy layered cathode material for sodium-ion batteries that shows improved performance in terms of capacity and stability.

## Contribution

The novelty lies in the synthesis of a high-entropy layered cathode with single grain morphology using spray pyrolysis, leading to enhanced battery performance.

## Key findings

- The cathode achieved a high specific capacity of ~180 mAh g−1 at 0.08 C.
- It showed 69% capacity retention after 300 cycles at 1C.
- The material exhibited high coulombic efficiency (>99.5%).

## Abstract

A major obstacle in the advancement of sodium‐ion batteries (SIBs) is the development of cathode active materials (CAMs) that offer both high specific capacity and long‐term cycling stability. Among the various candidates, layered CAMs have attracted significant attention. In this work, we synthesized a high‐entropy layered CAM with composition (Na0.52Ti0.19Mn0.19Fe0.21Ni0.21Co0.20O2) using a spray pyrolysis technique, yielding large (0.75 µm on average) and separated grains. The resulting material comprises a P3–O3 layered oxide mixture, along with ∼20% rock‐salt and spinel phases. This CAM demonstrates a high specific capacity (∼180 mAh g−1 at 0.08 C), excellent rate capability (69% retention after 300 cycles at 1C), and high coulombic efficiency (>99.5%). In comparison, a CAM of identical composition synthesized via a conventional sol–gel method, exhibiting an agglomerated microstructure, showed lower capacity and retention, consistent with literature reports. These findings highlight the advantages of combining high entropy design and cathode morphology in developing next‐generation cathodes for SIBs.

We produced a multiphase high entropy layered cathode with nominal composition Na0.52Ti0.19Mn0.19Fe0.21Ni0.21Co0.20O2 and single grain morphology, which demonstrated enhanced specific capacity (∼180 mAh g−1 at 0.08 C), excellent rate capability (69% retention after 300 cycles at 1C), and high coulombic efficiency (>99.5%).