Ab Initio-Based Structural and Thermodynamic Aspects of the Electrochemical Lithiation of Silicon Nanoparticles

Abstract

We reported the theoretical understandings of the detailed structural and thermodynamic mechanism of the actual lithiation process of silicon nanoparticle systems based on atomistic simulation approaches. We found that the rearrangement of the Si bonding network is the key mechanism of the lithiation process, and that it is less frequently broken by lithiation in the smaller sizes of Si nanoparticles. The decreased lithiation ability of the Si nanoparticles results in the lithiation potential being significantly lower than that of crystalline silicon phases, which impedes the full usage of the theoretical maximum capacity. Thus, nanosized Si materials could have a negative effect on performance if they become too fine-sized. These findings provide a detailed view of the electrochemical lithiation process of silicon nanoparticles (Si NPs) and engineering guidelines for designing new Si-based nanostructured materials.

Ab Initio Molecular Dynamics Simulation Study on Phosphorus/Boron Co-Doped Si Nanocrystals/SiO2 Core/Shell Structures

“…The second peak position is around 3–4.3 Å. This distribution corresponds to the Si–Si bond distribution in amorphous silicon and the Si–Si bond distribution in the amorphous SiO 2 matrix, which is consistent with results reported in the literature. , The first peak position of the Si–O RDF is around 1.6–1.7 Å, which is consistent with the bond length of the Si–O bond at around 1.6 Å. Overall, the minimal change at a temperature of 1300 K demonstrates the stability of the SiO 2 matrix.…”

“…On the other hand, the VDOS curve of B impurities exhibits an increase in peak intensity at the position of 15 THz when doped at a low concentration. 44,45 The first peak position of the Si−O RDF is around 1.6−1.7 Å, which is consistent with the bond length of the Si−O bond at around 1.6 Å. Overall, the minimal change at a temperature of 1300 K demonstrates the stability of the SiO 2 matrix.…”

Modeling and simulations for 2D materials: a ReaxFF perspective

“…The ReaxFF reactive force field method developed by van Duin et al for hydrocarbons [19] is a bondorder dependent potential where charge on each atom is determined based on the polarizable charge method [47], potentially suitable to model any type Illustration of the scope of this review which focuses on ReaxFF force fields and their applications to 2D materials categorized into six subgroups: (i) TMDs [24][25][26], (ii) hybrid materials [27][28][29][30], (iii) graphene/h-BN [31][32][33][34], (iv) MXenes [35][36][37][38], (v) group III materials [39][40][41][42] and (vi) group IV and V materials [43][44][45][46]. Reprinted with permission from [24].…”

“…This study provides important insight in the formation mechanism and optoelectronic properties of ZnO grown by ALD technique. Lee et al [28] engineered silicon nanoparticles to improve the capacity and performance of lithium-ion batteries (LIBs). For this, they performed a comparative study of the lithiation process of a silicon nanoparticle and crystal systems using ReaxFF simulations.…”

Theoretical bases of simulation the processes of formation and interaction of nanoparticles in a gas media

“…Математическое моделирование позволяет сократить издержки на проведение экспериментов, а также изучить фундаментальные закономерности, возникающие в процессе синтеза и формирования нанокластеров. В качестве математических моделей для исследования свойств наноматериалов в настоящее время используются аппараты квантовой механики [23,24], молекулярной динамики [25,26], статистические подходы Монте-Карло [27,28], модели классической термодинамики [29,30], методы моделирования мезо-и микромасштаба [31,32]. Модели квантовой механики, наряду со своей высокой точностью, вследствие значительных объемов вычислений ограничены небольшим размером исследуемой наносистемы.…”