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, Cu0.05WNb11.95O33 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.