基于Ti基MXene的储钠负极及其性能调控机制

Sodium storage anode based on titanium-based MXene and its performance regulation mechanism

二维MXene材料具有大且可调节的层间距,是一类备受关注的钠离子电池负极材料。为探究MXene材料储钠性能的调控机制,本工作选择Ti基碳化物MXene为目标材料,采用第一性原理计算预测和实验验证相结合的方法,研究了组成成分和结构调控对其储钠性能的影响。组成成分调控包括官能团取代和N对C的置换,结构调控主要是构建Ti_(3)C_(2)T_(x) MXene与过渡金属硫属化合物的异质结构。研究结果表明,含氧官能团和异质结构能够扩大MXene材料的层间距,防止层间堆叠;N置换可以增强电荷传输,有利于提高材料的结构稳定性和导电性,从而提高材料的比容量。其中构建异质结构对材料的性能改善作用最为显著。研究结果可为钠离子电池负极材料的选材提供理论依据,有助于开发高性能MXene基储钠负极材料。此外,本工作提出的分析方法也可以扩展应用到金属离子电池电极材料的结构和性能研究中。

One class of sodium-ion battery anode materials that has received a lot of attention is two-dimensional MXene materials with significant and controllable interlayer spacing.The titanium-based carbide,MXene,is chosen as the study’s target material to investigate the mechanisms that control how well these materials store sodium.The first-principle calculation prediction and experimental verification method is used to investigate the effects of composition and structure regulation on sodium storage performance.While structural regulation entails creating a heterostructure of Ti_(3)C_(2)T_(x) MXene and transition metal chalcogenides,composition regulation entails functional group substitution and nitrogen replacement with carbon.According to findings,heterostructures and the functional group-O can increase the interlayer space and prevent the MXene from stacking its interlayers;N can be replaced to improve charge transfer,which helps to increase stability and conductivity and raise the material’s specific capacity.Among them,the creation of heterostructures has the most notable improvement in terms of all-around performance.This study provides a theoretical framework for choosing anode materials for sodium-ion batteries,which are helpful in creating highperformance MXene-based sodium storage anode materials.Additionally,the analysis method suggested in this work can be expanded to the research on the structure and characteristics of electrode materials for metal-ion batteries.