Table_1_Nb-Doped MXene With Enhanced Energy Storage Capacity and Stability.DOCX

MXenes present unique features as materials for energy storage; however, limited interlayer distance, and structural stability with ongoing cycling limit their applications. Here, we have developed a unique method involving incorporating Nb atoms into MXene (Ti3C2) to enhance its ability to achieve higher ionic storage and longer stability. Computational analysis using density functional theory was performed that explained the material structure, electronic structure, band structure, and density of states in atomistic detail. Nb-doped MXene showed a good charge storage capacity of 442.7 F/g, which makes it applicable in a supercapacitor. X-ray diffraction (XRD) indicated c-lattice parameter enhancement after Nb-doping in MXene (from 19.2A° to 23.4A°), which showed the effect of the introduction of an element with a larger ionic radius (Nb). Also, the bandgap changes from 0.9 eV for pristine MXene to 0.1 eV for Nb-doped MXene, which indicates that the latter has the signature of increased conductivity due to more metallic nature, in support of the experimental results. This work presents not only the effect of doping in MXene but also helps to explain the phenomena involved in changes in physical parameters, advancing the field of energy storage based on 2D materials.MXenes作为储能材料具备独特的优异性能，但有限的层间距以及循环过程中的结构稳定性不足限制了其实际应用。本研究开发了一种独特的改性方法，将铌（Nb）原子掺入MXene（Ti3C2）中，以提升其离子存储能力与循环稳定性。我们通过密度泛函理论（density functional theory）开展了计算分析，从原子尺度详细阐释了该材料的晶体结构、电子结构、能带结构以及态密度。掺铌MXene展现出442.7 F/g的优异比电容，可应用于超级电容器（supercapacitor）。X射线衍射（X-ray diffraction, XRD）测试结果表明，掺铌后MXene的c轴晶格参数从19.2 Å提升至23.4 Å，印证了引入更大离子半径元素（铌）所带来的层间距调控效果。同时，其带隙从原始MXene的0.9 eV降至掺铌MXene的0.1 eV，表明后者因更显著的金属性而具备更高的导电性，这与实验观测结果相符。本研究不仅揭示了掺杂改性对MXene的调控作用，还阐明了其物理参数变化背后的内在机制，推动了基于二维材料的储能领域发展。