Prospective Life Cycle Assessment of Synthetic Graphite Manufactured via Electrochemical Graphitization

Abstract

Lithium-ion batteries (LIBs) are expected to play a crucial role in meeting many of the clean energy-related goals. Due to its electrical properties such as good conductance, chemical inertness, and corrosion resistance, graphite is a very popular anode for LIBs. Traditional methods of producing battery-grade graphite (high purity >99%) include processing naturally mined graphite or manufacturing synthetic graphite via the Acheson process, which converts soft amorphous carbons such as petroleum coke into graphite by subjecting it to high temperature (up to 3000 °C) for prolonged periods of times (3−5 days). However, due to a lack of abundant high purity natural graphite sources, synthetic graphite is the preferred choice for many LIBs. A new synthetic electrochemical graphitization method that subjects the amorphous carbon precursor submerged in a molten salt mixture to a constant cathodic polarization (against a graphitic anode) has been discovered that has significantly lower graphitization temperatures (∼800 °C) and reduced graphitization time (3−6 h). Furthermore, the method can accept a higher variety of carbon precursors compared to the Acheson process. A prospective life cycle assessment (LCA) is conducted on this new method and compared against the traditional processes. The laboratory-scale demonstration of the method is used to build an inventory, which through various assumptions is scaled up to a commercial scale. An additional scenario is also considered with a biomass-derived carbon precursor for the graphite. The results from the LCA show that while the laboratory scale process is similar to the Acheson process and natural flake graphite in terms of impact, the scaled-up process is drastically better than the Acheson process in all environmental categories. Using a coconut shell-derived biomass precursor has a higher impact due to its manufacturing in Indonesia, as the Indonesian energy grid is highly fossil fuel dependent. Therefore, the biomass carbon may have a higher impact than petroleum coke dependent on the location of production of biomassderived carbon black. The LCA has identified the molten salt�CaCl 2 �as a potential hotspot and suggests other salts should be considered. The new method shows promise in this early stage LCA in improving the environmental performance of graphite (and by relation LIBs) and therefore needs to be explored more in terms of its commercial viability.

Salt-assisted synthesis of advanced carbon-based materials for energy-related applications

“…Furthermore, this method is available for a wide range of carbon precursors. 118 Besides its use as an anode for batteries, graphite is a versatile precursor for preparing graphene. Although mechanical exfoliating has been very popular to date, the efficiency and the quality of the graphene are not excellent.…”

Quantification of the Carbon-Coating Effect on the Interfacial Behavior of Graphite Single Particles

“…Graphite has been widely used as the major market share (>90%) of anode materials since lithium-ion batteries (LIBs) were commercialized. Artificial graphite consumes high energy due to the granulation and high-temperature graphitization processes, and carbon emission is increased. , Natural graphite (NG) is abundant in the earth’s crust with excellent crystal arrangement, which meets the low-carbon environmental protection requirements with the simple purification process. , However, natural graphite particles suffer the slow intercalation of Li + and reduced ion transfer rate because of the inappropriate orientations of the graphite layers. Moreover, due to the low Li + diffusion kinetics of natural graphite during fast charging and discharging, a severe amount of Li + electroplates at the outer edge of the carbon layer form the lithium dendrites which will make the safety issue of the battery. − Consequently, the slow kinetics of Li + at the interface of natural graphite is one of the key factors that should be considered to obtain a high current performance.…”

Environmental Impact Prediction of a New Tire Vulcanization Activator

“…As the new activator is not produced at a commercial scale yet, a prospective LCA (pLCA) is needed for a fair comparison against commercially available ZnO. pLCA has been used to predict the future environmental impacts of emerging technologies over their full life cycle. − pLCA allows an emerging technology to be modeled at a future, more-developed phase while it is still in early development. − Alternative techniques or products can be evaluated to propose a design with lower environmental impacts. , Case studies on nanomaterials, aerogels, and graphite showed that environmental impacts decrease when emerging technologies are scaled from laboratory to industrial scale. ,, …”

“…15,26 Case studies on nanomaterials, aerogels, and graphite showed that environmental impacts decrease when emerging technologies are scaled from laboratory to industrial scale. 15,17,27 The goal of this study was to predict the environmental impacts of synthesizing the new ZnO@SiO 2 vulcanization activator at an industrial scale in 2030. pLCA was used to model the manufacturing of the new activator at technology readiness levels (TRLs) 5, 6, and 9 by using the frameworks of van der Hulst et al 25 and Piccinno et al 28 We investigated the change in environmental impact with increasing TRL, the contribution of upscaling steps, the synthesis hotspots, and external developments until 2030. We also compared two predictions of TRL 9, one using data from TRL 5 and the other from TRL 6, to assess the influence of the pLCA prediction's starting point.…”