论文标题
通过化学功能化，在完美晶格匹配的MXENE和1T-MOS2异质结构中扁平化激活
Flatten the Li-ion Activation in Perfectly Lattice-matched MXene and 1T-MoS2 Heterostructures via Chemical Functionalization
论文作者
论文摘要
由于其超薄金属结构，MXENE及其衍生物引起了对电池和超级电容器等能源的潜在应用的极大关注。但是，基于MXENE的混合动力车中离子和电子动力学的复杂性通常是设备集成所需的，触发其应用的挑战和机遇。在本文中，研究了由TI3C2T2（T = NONE，O和F原子）和金属MOS2（1T期）组成的异质结构的原型。通过密度函数理论，我们研究了TI3C2T2/1T-MOS2的锂离子电池（LIB）中的界面电子变化，热激活和阳极性能。我们发现，MXENE中的不同表面原子基可以显着改变Ti3c2t2和1T-MOS2界面中Li原子的亲和力，氧化还原反应和动力学。通过检查LI的三种可能途径，通过攀登图像螺纹弹性带（CI-NEB）和AB-Initio分子动力学（AIMD）模拟，扩散曲线从裸露到O-和F端端的TI3C2 MXENE显着平坦，并从0.80和0.22和0.22和0.29 evem逐渐降低，并相应地降低了激活屏障1.20x10-6至2.75x10-6，1.70x10-4 cm2 S-1。使用O或F的功能化通过打破两层之间的强相互作用，消除了LI插入的空间障碍，并在此期间提供了额外的吸附位点，以进行LI扩散。我们的工作表明，表面官能团在TI3C2T2/1T-MOS2修改中起着重要作用，而Ti3C2F2/1T-MOS2具有高扩散系数，理论能力可能是LIBS的有前途的阳极材料。
MXene and its derivatives have attracted considerable attention for potential application in energy storage like batteries and supercapacitors owing to its ultrathin metallic structures. However, the complexity of the ionic and electronic dynamics in MXene based hybrids, which are normally needed for device integration, triggers both challenges and opportunities for its application. In this paper, as a prototype of metallic hybrids of MXene, heterostructures consisting of Ti3C2T2 (T= None, O and F atoms) and metallic MoS2 (1T phase) are investigated. Through density functional theory, we investigate the interfacial electronic variation, thermal activation, and anode performance in the lithium-ion battery (LIB) of Ti3C2T2/1T-MoS2. We found that different surface atomic groups in MXene can significantly alter the affinity, redox reaction and kinetics of Li atoms in the interface of the Ti3C2T2 and 1T-MoS2. Through examining the three possible pathways of Li by climbing image-nudged elastic band (CI-NEB) and ab-initio molecular dynamics (AIMD) simulation, the diffusion curve becomes significantly flattened from the naked to O- and F-terminated Ti3C2 MXene with activation barriers reducing from 0.80 to 0.22 and 0.29 eV, respectively, and room-temperature diffusion coefficients increasing from 1.20x10-6 to 2.75x10-6, 1.70x10-4 cm2 s-1, respectively. The functionalization with O or F eliminates the steric hindrance of Li intercalation by breaking the strong interaction between two layers and provides additional adsorption sites for Li diffusion in the meantime. Our work suggests that surface functional groups play a significant role in Ti3C2T2/1T-MoS2 modification and Ti3C2F2/1T-MoS2 with the high diffusion coefficient and theoretical capacity could be a promising anode material for LIBs.
