Phase Engineering of <scp>MXene</scp> Derivatives Via Molecular Design for High‐Rate Sodium‐Ion Batteries
Hui Zhang, Xingwu Zhai, Xin Cao, Zhihao Liu, Xinfeng Tang, Zhihong Hu, Hang Wang, Zhandong Wang, Yang Xu, Wei He, Wei Zheng, Min Zhou, ZhengMing Sun
Abstract
Since 2019, research into MXene derivatives has seen a dramatic rise; further progress requires a rational design for specific functionality. Herein, through a molecular design by selecting suitable functional groups in the MXene coating, we have implemented the dual N doping of the derivatives, nitrogen‐doped TiO 2 @nitrogen‐doped carbon nanosheets (N‐TiO 2 @NC), to strike a balance between the active anatase TiO 2 at low temperatures, and carbon activation at high temperatures. The NH 3 reduction environment generated at 400 °C as evidenced by the in situ pyrolysis SVUV‐PIMS process is crucial for concurrent phase engineering. With both electrical conductivity and surface Na + availability, the N‐TiO 2 @NC achieves higher interface capacitive‐like sodium storage with long‐term stability. More than 100 mAh g −1 is achieved at 2 A g −1 after 5000 cycles. The proposed design may be extended to other MXenes and solidify the growing family of MXene derivatives for energy storage.