Synthesis and Characterization of Porous NiSi-Si Composite Anode Materials for Lithium-Ion Batteries
Date Issued
2007
Date
2007
Author(s)
Chao, Sung-Chieh
DOI
zh-TW
Abstract
The main objective of this research is to explore new materials based on silicon for lithium-ion battery. In the last decade, silicon has attracted much attention because it has the highest specific capacity (~3600 mAh/g) for any of anode materials studied to date. However, Si undergoes a dramatic volume change during cycling and possesses intrinsically poor conductivity, resulting in the mechanical instability and poor cyclability, retard its commercial application.
From the view point of stabilizing electrode structure and increasing the conductivity, porous NiSi-Si composite anode material has been synthesized by high-energy ball milling, of mixture of Ni and Si and subsequent dissolution of un-reacted Ni. The preset intra-particle voids have been shown to help to accommodate volume expansion arising form the alloying of Si. Furthermore, Synchrotron XRD indicates that the NiSi component is active toward Li alloying, and Ni2Si is formed during Li alloying. Both preset intra-particles void and presence of Ni2Si help to maintain the integrity of the electrode, resulting in much reduced thickness expansion, as compared with pure Si electrode.
In addition, the morphology and composition of SEI layer formation on Si or C-Si anode using LiPF6 in EC/EMC as electrolyte have been carried by means of SEM and XPS analysis. Superficial deposition is vivid even after only one cycle because of the existence of –OH/H2O bounded on SiO2 surface. After coating carbon on Si surface, the formation of Si oxide is reduced.
From the view point of stabilizing electrode structure and increasing the conductivity, porous NiSi-Si composite anode material has been synthesized by high-energy ball milling, of mixture of Ni and Si and subsequent dissolution of un-reacted Ni. The preset intra-particle voids have been shown to help to accommodate volume expansion arising form the alloying of Si. Furthermore, Synchrotron XRD indicates that the NiSi component is active toward Li alloying, and Ni2Si is formed during Li alloying. Both preset intra-particles void and presence of Ni2Si help to maintain the integrity of the electrode, resulting in much reduced thickness expansion, as compared with pure Si electrode.
In addition, the morphology and composition of SEI layer formation on Si or C-Si anode using LiPF6 in EC/EMC as electrolyte have been carried by means of SEM and XPS analysis. Superficial deposition is vivid even after only one cycle because of the existence of –OH/H2O bounded on SiO2 surface. After coating carbon on Si surface, the formation of Si oxide is reduced.
Subjects
鋰離子電池
矽
SEI膜
多孔結構
Lithium-ion batteries
silicon
high energy ball milling
SEI film
Porous structure
SDGs
Type
thesis
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