High‐Throughput Calculation Identifying Boron and Tin Dopants for Optimizing Na ₄ Fe ₃ (PO ₄ )

ABSTRACT

Na ₄ Fe ₃ (PO ₄ ) ₂ P ₂ O ₇ (NFPP) cathode material exhibits a robust structural stability, conferring long cycle life for sodium‐ion batteries. Nevertheless, the intrinsically low electronic and ionic conductivities of NFPP impede its widespread practical applications. Herein, a high‐throughput density functional theory screening paradigm coupled with experimental validation, was employed to systematically identify and optimize dopants for NFPP, enhancing its electrochemical performances. Twenty‐five candidate elements were rigorously evaluated across multifaceted criteria, encompassing doping formation energy, bandgap, Na ion diffusion energy barrier, and the integrated crystal orbital Hamilton population of metal‐oxygen bond. Thermodynamic analyses reveal that those elements with ionic radii close to Fe ²⁺ exhibit more negative doping formation energies. Subsequent assessments by the density functional theory calculations identify Sn and B as two new dopants, markedly elevating both electronic and ionic conductivities to make NFPP an efficient mixed conductor. Simultaneously, these two dopants reinforce metal‐oxygen bond strength, eventually boosting lattice stability. Experimental verifications demonstrate that Sn‐ and B‐doped NFPP deliver superior rate performance and enhanced discharge voltage retention rate compared to the pristine sample. These experimental findings firmly validate our proposed computation‐to‐experiment workflow and high‐throughput screening framework, establishing an exclusive framework for the rational doping strategy in polyanionic electrode materials toward advanced sodium‐ion batteries.