Pseudo-Jahn–Teller Effect-Regulated Structural Distortion in WNb₁₂O₃₃ Triggering Highly Stable and Fast-Charge Lithium Storage

WNb₁₂O₃₃ with a ReO₃ shear structure offers high lithium storage capacity but suffers from poor electron/ion transport. Hence, exploring an effective strategy aimed at enhancing intrinsic conductivity while maintaining a robust crystal framework is a significant challenge for advancing WNb₁₂O₃₃ as a promising anode. Here, a pseudo-Jahn-Teller effect-driven local structural distortion regulation strategy is demonstrated in WNb₁₂O₃₃ through quantifying Cu²⁺ occupancy at Nb sites in NbO₆ octahedra. XRD results reveal the change in crystal structure symmetry. The DFT calculation confirms the alteration of the bandgap and Nb-O bond length, which not only exhibits enhanced electronic conductivity but also optimizes the adsorption behavior of Li⁺. Accordingly, the Cu²⁺-doped WNb₁₂O₃₃ offers a high reversible specific capacity of 272.6 mAh g^-1, along with the Li⁺ diffusion coefficient promoted to 5.26 × 10^-12 cm² s^-1. Moreover, it exhibits remarkable structural stability during the cycling process, featuring a reversible single-phase transition. As a result, Cu_0.05WNb_11.95O₃₃ material provides high-rate capacity (147.2 mAh g^-1 at 10 A g^-1) and cycling performance (84.3% capacity retention at 5 A g^-1 after 1000 cycles). This work provides a new perspective for the design and customization of shear structures and a basis for the rapid energy storage applications of WNb₁₂O₃₃.