New paper published on P2-type layered high-entropy oxides as sodium-ion cathode materials in Materials Futures

New paper published in Materials Futures. Sodium-deficient, P2-type layered oxides are promising cathodes for sodium-ion batteries. Their open sodium cation transport pathways lead to low diffusion barriers and enable high charge/discharge rates. However, a phase transition from P2 to O2 structure occurring above 4.2 V and metal dissolution at low potentials upon discharge results in rapid capacity degradation. In this work, we demonstrate the positive effect of configurational entropy on the stability of the crystal structure during battery operation. The high-entropy cathode material shows lower structural transformation and Mn dissolution upon cycling in a wide voltage range from 1.5 V to 4.6 V. Advanced operando techniques and post-mortem analysis were used to thoroughly probe the underlying reaction mechanism. Overall, the high-entropy strategy is a promising route for improving the electrochemical performance of P2 layered oxide cathodes for advanced sodium-ion battery applications.