Ferroelectric‐Polarization‐Driven Structural Engineering of Bi ₃ Nb ₁₇ O ₄₇ Anodes for High‐Performance Lithium‐Ion Batteries

ABSTRACT Metal‐ion batteries face challenges in optimizing electrode materials to enhance capacities and structural stability. Traditional strategies like defect engineering and elemental doping show limitations, necessitating innovative approaches. Herein, we propose a ferroelectric‐polarization strategy to modulate the crystal structure of Bi ₃ Nb ₁₇ O ₄₇ , a tungsten bronze (TTB)‐type anode material with a theoretical capacity of 308 mAh g ⁻¹ but restricted Li ⁺ storage sites. The polarization induces asymmetric displacements of Nb ⁵⁺ and inward contraction of O ²⁻ , enlarging the Li ⁺ ‐storage cavities by approximately 8%. This structural tailoring significantly boosts the reversible capacities of Bi ₃ Nb ₁₇ O ₄₇ by 36%−55% across various current densities (0.1−10 C). Furthermore, the enlarged Li ⁺ ‐storage cavities enable smaller unit‐cell‐volume fluctuations, resulting in its enhanced cycling stability (84.9% capacity retention after 1000 cycles at 5 C). This work pioneers electric‐field‐driven structural engineering in electrochemical energy‐storage materials, offering a transformative modification strategy for high‐performance metal‐ion batteries.