Morphology engineering of silicon nanoparticles for better performance in Li-ion battery anodes

Abstract

Amorphous silicon nanoparticles were synthesized through pyrolysis of silane gas at at temperatures ranging from 575 to 675°C. According to the used temperature and silane concentration, two distinct types of...

Stoichiometry-Controlled Reversible Lithiation Capacity in Nanostructured Silicon Nitrides Enabled by in Situ Conversion Reaction

“…35 Such a method has been successfully demonstrated for the preparation of nanoparticles of pure Si and allows to efficiently control not only the sizes of nanoparticles but also their morphologies by controlling nucleation and growth in the gas phase. 36 For the synthesis of SiN x , the reaction temperature was selected to target the preparation of amorphous particles, and precursor's ratio and flow rate were adjusted to synthesize particles of different sizes and chemical compositions. Within the present work, four examples of SiN x were selected for further study to elucidate the influence of nitrogen content (chemical composition) and particle size on the electrochemical performance and stability of the prepared materials.…”

“…Amorphous SiN x nanoparticles of several sizes and stoichiometries were synthesized by copyrolysis of ammonia (NH 3 ) and silane (SiH 4 ) through homogeneous nucleation in the gas phase using a free space reactor . Such a method has been successfully demonstrated for the preparation of nanoparticles of pure Si and allows to efficiently control not only the sizes of nanoparticles but also their morphologies by controlling nucleation and growth in the gas phase . For the synthesis of SiN x , the reaction temperature was selected to target the preparation of amorphous particles, and precursor’s ratio and flow rate were adjusted to synthesize particles of different sizes and chemical compositions.…”

“…However, it should be noted that initial capacity and capacity at the end of cycling is the highest for SiN 0.39 -NP and lowest for SiN 0.39 -NP, with SiN 0.63 -NP in the middle. The samples with the lowest nitrogen content experience the biggest changes upon cycling making them somewhat similar to Si-based electrodes which experience a large drop in capacity after formation cycles . Interestingly, SiN 0.69 -μP exhibited only somewhat lower capacity retention than SiN 0.63 -NP, at 79.3%, despite consisting of larger, micron-sized particles, indirectly confirming the presence of the additional structural transformations taking place during long-term cycling, which leads to slow degradation of the material.…”

“…The general synthesis of amorphous Si nanoparticles through pyrolysis of SiH 4 in hot wall free space CVD reactor was described elsewhere. 36 In the present work, amorphous SiN x particles were synthesized using a similar procedure modified by introducing NH 3 as nitrogencontaining precursor into reactor. The samples described herein were synthesized with SiH 4 :NH 3 flow rate ratios ranging from 1:1 to and pyrolysis temperatures ranging from 600 to 650 °C.…”

Carbon Anode in Carbon History

“…However, the aggregation of Si nanoparticles and electrolyte was inevitable and capacity fading was caused. There were many attempts to solve the aggregation problem [423][424][425][426], and silicon expansion was relieved to some extent and nanoparticles aggregation was further minimized. A more effective method consists of encapsulating a metal oxide into a graphene layer by co-assembling between negatively charged graphene oxide and positively charged oxide nanoparticles [427].…”