High Configurational Entropy Engineered Hollow Microspheres Layered Mn-Based Cathode Enabling Stress Self-Dissipation...

High-voltage (>4.3 V) P2-type Mn-based layered oxides have emerged as promising cathode materials for sodium-ion batteries (SIBs), yet its practical application is impeded by irreversible oxygen redox reaction (ORR), Jahn-Teller distortion, and microcrack formation. Herein, an innovative high configurational entropy engineered hollow microsphere of Na_0.67Li_0.18Co_0.08Mn_0.71Mg_0.13Cu_0.08O₂ (HEHM-NMO) as cathode material is proposed to realize stress self-dissipation and sustainable cationic/anionic redox, thereby endowing wide-temperature (-10-60 °C) workability for SIBs. It is found that the high configurational entropy enhances the electronic structure disorder (ESD) for impeding undesired oxygen escape and also optimizes the orbital hybridization (O 2p-Mn 3d) to induce reversible ORR (O^2-/O₂^n-). By coupling high configurational entropy with hollow microspheres, spontaneous stress dissipation in HEHM-NMO is achieved during the cycling process. As a result, the HEHM-NMO cathode can provide an ultrahigh initial charge capacity of 171.7 mA h g^-1 with an initial Coulombic efficiency of 92.9% at 1.5-4.5 V and still enable a retention of 85.8% after 300 cycles at 2C. Notably, it also shows a wide-temperature (-10-60 °C) workability, delivering a capacity of 152.0 mA h g^-1 at -10 °C and 192.7 mA h g^-1 at 60 °C (average decay: 0.12% per cycle). This work provides atomic-level insights into entropy-dominant structural and electronic regulation for activating reversible oxygen redox.