Carbon-Coated Silicon Nano-Composites as Negative Electrodes for Lithium Batteries and Electrically Conductive Adhesives Containing Ag-Plated Graphite Particles
Date Issued
2014
Date
2014
Author(s)
Chueh, Ti-Chiang
Abstract
This thesis study contains two parts. The first part is carbon-coated silicon nano-composites as negative electrodes for lithium-ion batteries. The second part is electrically conductive adhesives (ECAs) containing Ag-plated graphite particles.
An effective method to produce carbon-coated silicon nano-composites as a high-capacity anode material for rechargeable lithium-ion batteries has been investigated. Initially, silicon particles mixed in different carbon precursor solutions via ultrasonication were prepared by thermal treatment in inert gas at elevated temperature (600 - 1000 oC) to form a homogeneous carbon-coated layer onto the surface of the silicon nanoparticles. The effects of the processing temperature, the duration of thermal treatment, silicon particle size, and the mass ratio of carbon precursor to silicon were investigated in detail. All of these parameters significantly influence the cyclic charge/discharge performance of the carbon-coated Si nanocomposites. Carbon-coated Si nano-composites by using honey as carbon precursor in Argon gas at 1000 oC showed the better cycling performance, with a capacity loss of less than 0.42 % per cycle and retaining a specific capacity of 2355 mAh/g beyond 51 cycles, which is much better than the graphite anode. Furthermore, the capacity fading and lithiation mechanisms of silicon and carbon-coated silicon particles also been measured and studied by cycling tests. The dimensional stability of the Si nanoparticles provided by the carbon nano-coating enhances the electric contact of silicon particles and it seems to be the leading reason for this better improved electrochemical performance.
Besides, the conductivities of electrically conductive adhesives (ECAs) containing silver-coated graphite particles by self-activated deposition has been investigated. A novel silver self-activated electroless deposition on graphite designed as conductive filler were employed, and a uniform silver coating with minimal agglomeration on graphite surface was obtained. Furthermore, the electrical resistivity of electrical conductive adhesives containing silver-plated graphite powders have also been investigated in this study. The best result of the electrical resistivity of epoxy-based conductive adhesives obtained is 5.16 × 10-4 Ω-cm for 60 wt% of silver-plated graphite powders. The weight percentage of silver in this epoxy-based adhesive is reduced to 56.6 wt%, which is much less than that of the regular silver conductive adhesives.
Subjects
鋰離子電池
矽
碳矽複合材料
蜂蜜
石墨鍍銀
導電膠
銀自身活化
SDGs
Type
thesis
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