Shirvani Fatemeh, Jafari Mohammad Reza, Shokri Aliasghar
Department of Condensed Matter Physics, Faculty of Physics, Alzahra University, Tehran, Iran.
Department of Theoretical Physics and Nano, Faculty of Physics, Alzahra University, Tehran, Iran.
Sci Rep. 2023 Sep 21;13(1):15680. doi: 10.1038/s41598-023-42954-w.
The two-dimensional structures of transition metal nitride and carbide, TiN, and TiC have been alloyed with lithium (Li) in replacement of Ti, and their Li-ion applicability has been investigated using density functional theory and general gradient approximation. The alloy composition of [Formula: see text], 0.25, 0.375, and 0.5 have been considered and the stability of the alloys has been proved by cohesive energy and phonon density of states results. Moreover, the bond lengths between atoms as structural properties have been studied for these alloy structures. The largest peak of quantum capacitance and the largest negative value of surface storage charge are for alloy composition of TiC with [Formula: see text] with the values of 909.79 [Formula: see text]F/cm[Formula: see text] and [Formula: see text]C/cm[Formula: see text], respectively. Moreover, the results of the quantum capacitance and surface storage charge as a function of voltage for all Li alloy compounds are in the range of excellent supercapacitors and could have good potential to use as an electrode in the capacitor of Li-ion batteries. Furthermore, the electronic density of states of this group of alloys represents metallic behavior and therefore electrode material. In addition, the diffusion coefficient at temperatures of 77 and 300 K has been calculated using molecular dynamic calculations, and its lowest and largest values are [Formula: see text] cm[Formula: see text]/s (at 77 K) and [Formula: see text] cm[Formula: see text]/s (at 300), respectively. Plus, the largest value of electrical conductivity per relaxation time at 300 K belongs to Li[Formula: see text]Ti[Formula: see text]C with a value of [Formula: see text]/([Formula: see text] m s).
过渡金属氮化物和碳化物TiN及TiC的二维结构已与锂（Li）合金化以取代Ti，并使用密度泛函理论和广义梯度近似研究了它们的锂离子适用性。考虑了合金组成[化学式：见正文]、0.25、0.375和0.5，结合能和声子态密度结果证明了合金的稳定性。此外，还研究了这些合金结构作为结构特性的原子间键长。量子电容的最大峰值和表面存储电荷的最大负值出现在TiC合金组成[化学式：见正文]中，其值分别为909.79 [化学式：见正文]F/cm[化学式：见正文]和[化学式：见正文]C/cm[化学式：见正文]。此外，所有锂合金化合物的量子电容和表面存储电荷随电压的变化结果处于优秀超级电容器的范围内，并且在锂离子电池的电容器中用作电极具有良好潜力。此外，这组合金的电子态密度表现出金属行为，因此可作为电极材料。另外，使用分子动力学计算计算了77 K和300 K温度下的扩散系数，其最低值和最高值分别为[化学式：见正文] cm[化学式：见正文]/s（在77 K时）和[化学式：见正文] cm[化学式：见正文]/s（在300 K时）。此外，300 K时每个弛豫时间的最大电导率值属于Li[化学式：见正文]Ti[化学式：见正文]C，值为[化学式：见正文]/([化学式：见正文] m s)。
