Tuning crystal field stabilization energy through configurational entropy design in high-entropy oxide sodium-ion battery cathodes

Zhou, Y. and Yu, Z. and Ouyang, B. and Yuan, Y. and Wang, Y. and Qin, F. and Lei, C. and Yang, Y. and Liu, W. and Ning, F. and Liu, K. and Chen, T. (2026) Tuning crystal field stabilization energy through configurational entropy design in high-entropy oxide sodium-ion battery cathodes. Materials Today: 103192. (In Press)

Text (Tuning Crystal Field Stabilization Energy through Configurational Entropy Design in High-Entropy Oxide Sodium-Ion Battery Cathodes)
Tuning_Crystal_Field_Stabilization_Energy_through_Configurational_Entropy_Design_in_High-Entropy_Oxide_Sodium-Ion_Battery_Cathodes.pdf - Accepted Version
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Text (Tuning Crystal Field Stabilization Energy through Configurational Entropy Design in High-Entropy Oxide Sodium-Ion Battery Cathodes)
Tuning_Crystal_Field_Stabilization_Energy_through_Configurational_Entropy_Design_in_High-Entropy_Oxide_Sodium-Ion_Battery_Cathodes.pdf - Accepted Version
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Abstract

High entropy layered oxides have emerged as promising cathode materials for sodium-ion batteries due to their structural tunability and enhanced phase stability. However, a fundamental understanding of how configurational entropy influences the local electronic environment and structural robustness remains elusive. A novel high-configurational-entropy O3-type layered oxide, Na0.85Mn0.40Ni0.25Fe0.1Cu0.1Li0.05Ti0.05Sn0.05O2 (HE-NMNFCLTS), was designed and synthesized as a promising cathode material for sodium-ion batteries. By tailoring the configurational entropy, the crystal field stabilization energy (CFSE) of HE-NMNFCLTS is significantly enhanced: multi-elemental co-doping induces local distortion of MnO6 octahedra, leading to in-creased t2g orbital splitting and a notable improvement in CFSE, thereby stabilizing the crystal structure. Multidimensional characterization reveals its uniform strain distribution, effectively suppressing lattice mismatch and cation migration during Na+ (de) intercalation. Furthermore, HE-NMNFCLTS delivers a high initial discharge capacity of 137.7 mA h g−1 at 0.1 C (2–4.2 V), with 79.5 mA h g−1 retained at 10 C and 80 % capacity retention after 1000 cycles. First-principles calculations further re-veal the enhanced CFSE and a synergistic compensation effect that mitigates anisotropic strain in the TMO2 layers and narrows the bandgap to 0.189 eV, boosting both electronic and ionic conductivity. This work offers a new strategy for stabilizing layered oxide structures via entropy-driven CFSE modulation.