One-Step Formation of Silicon-Graphene Composites from Silicon Sludge Waste and Graphene Oxide via Aerosol Process for Lithium Ion Batteries

Abstract

Over 40% of high-purity silicon (Si) is consumed as sludge waste consisting of Si, silicon carbide (SiC) particles and metal impurities from the fragments of cutting wire mixed in ethylene glycol based cutting fluid during Si wafer slicing in semiconductor fabrication. Recovery of Si from the waste Si sludge has been a great concern because Si particles are promising high-capacity anode materials for Li ion batteries. In this study, we report a novel one-step aerosol process that not only extracts Si particles but also generates Si-graphene (GR) composites from the colloidal mixture of waste Si sludge and graphene oxide (GO) at the same time by ultrasonic atomization-assisted spray pyrolysis. This process supports many advantages such as eco-friendly, low-energy, rapid, and simple method for forming Si-GR composite. The morphology of the as-formed Si-GR composites looked like a crumpled paper ball and the average size of the composites varied from 0.6 to 0.8 μm with variation of the process variables. The electrochemical performance was then conducted with the Si-GR composites for Lithium Ion Batteries (LIBs). The Si-GR composites exhibited very high performance as Li ion battery anodes in terms of capacity, cycling stability, and Coulombic efficiency.

Waste Windshield-Derived Silicon/Carbon Nanocomposites as High-Performance Lithium-Ion Battery Anodes

“…However, the synthesis of silicon nanostructures requires toxic and/or expensive precursors. When considering the cost and environmental friendliness, some researchers have suggested using industrial waste or organic matter in nature such as rice husks and petrochemical waste as silicon sources instead of chemical precursors 16 – 19 . These eco-friendly precursors can reduce the precursor cost; however, the reduction of silica is a high-energy and high-cost process.…”

Thermal properties of porous ceramics manufactured by direct foaming using silicon sludge and silica fume

“…This is judged to be a weight reduction due to the dehydration reaction of adsorb and crystallized water (below 200°C), and combustion of carbon generated in the silica fume manufactured process [26,27]. In the case of Si sludge, a rapid weight increase was observed above 600°C, which is attributed to the oxidation reaction where Si combines with oxygen in the atmosphere [11,28]. Figure 4 shows the optical image of the porous ceramic specimen surface with varying amounts of Si sludge substitution.…”

“…Si sludge is a by-product generated during the processing of silicon wafers used in the manufacturing of semiconductor devices and solar cells. In the process of manufacturing silicon wafers by cutting a Si ingot, more than 40% of the ingot is discarded in the form of sludge [11,12]. The amount of Si sludge generated is expected to increase with the increasing use of silicon wafers, owing to the ongoing developments in the semiconductor and photovoltaic industries.…”

Glycol-Thermal Continuous Flow Synthesis of Graphene Gel

“…After solvent exchange to replace EG and remove the salt byproducts, the purified graphene gel can then dry in air to yield a densified xerogel, which is made of densely and yet disorderly packed crumpled sheets. This flow synthesis method could be extended to prepare a number of GO-based multifunctional composite materials, leveraging GO’s surfactant-like properties − to codisperse other materials such as carbon nanomaterials, conductive polymers, , biomass, silicon, metal and oxide nanoparticles, and many others. As a proof-of-concept, a coextrusion with polyaniline nanofibers, nickel, and carbon black (CB) was achieved (Figure S5).…”