Direct amination of Si nanoparticles for the preparation of Si@ultrathin SiO_x@graphene nanosheets as high performance lithium-ion battery anodes

Abstract

NH2-termitated Si nanoparticles with an ultrathin silica shell have been efficiently obtained by one-step reaction in ammonia-water-ethanol solution. Graphene nanosheets encapsulated Si @ ultrathin SiOx have been fabricated by selfassembly and thermal treatment. Because of the uniform utrathin SiOx shell and superior GNSs encapsulation structure, this material shows a reversible capacity of 2391.3 mAh g -1 , maintaining 1844.9 mAh g -1 after 50 cycles at the current density of 200 mA g -1 , and good rate and long cycle performance (~700 mAh g -1 at 2000 mA g -1 after 350 cycles) as well.

SiO2‐Enhanced Structural Stability and Strong Adhesion with a New Binder of Konjac Glucomannan Enables Stable Cycling of Silicon Anodes for Lithium‐Ion Batteries

“…In this work, molecular mechanics simulations have been performed to evaluate the interfacial adhesion energy between binders and active materials. [52][53][54] In contrast to the KGM binder, only few SA molecules are attached on the surface of Si(111) crystal plane ( Figure 1b). The calculated interfacial adhesion energy of the KGM/SiO 2 model is 0.205 J m −2 (Table S1, Supporting Information), which is significantly larger than 0.187 J m −2 for the KGM/Si(111) model, indicating the enhanced adhesion between the KGM binder and the surface SiO 2 layer after modification.…”

“…First, there are more polar hydroxyl groups in the KGM molecules compared with the SA molecules (Figure S1c,d, Supporting Information), enabling inherently higher viscosity and adhesivity when used as a binder for Si‐based anodes. Second, plentiful silanol groups (SiOH) will be formed on the surface of Si@SiO 2 nanoparticles, which increases possibilities to form more hydrogen bonds with the hydroxyl‐group enriched KGM binder and thus further enhances the structural integrity of the electrode …”

A facile in situ synthesis of nanocrystal-FeSi-embedded Si/SiOx anode for long-cycle-life lithium ion batteries

“…[27,[30][31][32] Simultaneously, a highly stable SEI can be formed on the surface of the amorphous SiO x , avoiding repeated formation of SEI film during cycles, which would lead to a decline in capacity. [33][34][35] The Si/SiO x electrodes showed a reversible capacity of 1280 mAh g -1 after 150 cycles at a rate of 0.2 C, and a high rate capability of ~1200 mAh g -1 at 10 C rate. [38] However, there are still some problems of the Si/SiO x nanocomposite, such as the poor conductivity, complicated synthesis process and high preparation cost, which limit their practical applications.…”

Supercritical Carbon Dioxide-Assisted Process for Well-Dispersed Silicon/Graphene Composite as a Li ion Battery Anode

“…Many researchers have reported methods for the fabrication of Si/graphene composites, in which they prepared the composite using GO 5 15 19 20 21 . Because GO can be dispersed in water to form a stable suspension, the method using GO suspension is a convenient route to prepare homogeneous graphene-based composites without graphene agglomeration.…”

“…GO has a negative charge resulting from ionization of its carboxylic acid and phenolic hydroxyl groups, which could exert electrostatic attraction with positively charged materials. To achieve such attraction, some researchers have tried to modify the surfaces of Si particles with surfactant, polymer, or silane 15 19 20 21 . Zhou et al .…”