Pseudo-Jahn–Teller Effect-Regulated Structural Distortion in WNb<sub>12</sub>O<sub>33</sub> Triggering Highly Stable and Fast-Charge Lithium Storage
Yingying Lei, Mingru Su, Shijie Wang, Jianchun Wu, Yu Zhou, Aichun Dou, Xueli Chen, Yunjian Liu
Abstract
WNb 12 O 33 with a ReO 3 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 WNb 12 O 33 as a promising anode. Here, a pseudo-Jahn–Teller effect-driven local structural distortion regulation strategy is demonstrated in WNb 12 O 33 through quantifying Cu 2+ occupancy at Nb sites in NbO 6 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 Cu 2+ -doped WNb 12 O 33 offers a high reversible specific capacity of 272.6 mAh g –1, along with the Li + diffusion coefficient promoted to 5.26 × 10 –12 cm 2 s –1 . Moreover, it exhibits remarkable structural stability during the cycling process, featuring a reversible single-phase transition. As a result, Cu 0.05 WNb 11.95 O 33 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 WNb 12 O 33 .