Browsing by Author "Eddy, Lucas"

Now showing 1 - 5 of 5
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    A scientific machine learning framework to understand flash graphene synthesis
    (Royal Society of Chemistry, 2023) Sattari, Kianoosh; Eddy, Lucas; Beckham, Jacob L.; Wyss, Kevin M.; Byfield, Richard; Qian, Long; Tour, James M.; Lin, Jian; NanoCarbon Center; Welch Institute for Advanced Materials
    Flash Joule heating (FJH) is a far-from-equilibrium (FFE) processing method for converting low-value carbon-based materials to flash graphene (FG). Despite its promises in scalability and performance, attempts to explore the reaction mechanism have been limited due to the complexities involved in the FFE process. Data-driven machine learning (ML) models effectively account for the complexities, but the model training requires a considerable amount of experimental data. To tackle this challenge, we constructed a scientific ML (SML) framework trained by using both direct processing variables and indirect, physics-informed variables to predict the FG yield. The indirect variables include current-derived features (final current, maximum current, and charge density) predicted from the proxy ML models and reaction temperatures simulated from multi-physics modeling. With the combined indirect features, the final ML model achieves an average R2 score of 0.81 ± 0.05 and an average RMSE of 12.1% ± 2.0% in predicting the FG yield, which is significantly higher than the model trained without them (R2 of 0.73 ± 0.05 and an RMSE of 14.3% ± 2.0%). Feature importance analysis validates the key roles of these indirect features in determining the reaction outcome. These results illustrate the promise of this SML to elucidate FFE material synthesis outcomes, thus paving a new avenue to processing other datasets from the materials systems involving the same or different FFE processes.
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    Battery metal recycling by flash Joule heating
    (AAAS, 2023) Chen, Weiyin; Chen, Jinhang; Bets, Ksenia V.; Salvatierra, Rodrigo V.; Wyss, Kevin M.; Gao, Guanhui; Choi, Chi Hun; Deng, Bing; Wang, Xin; Li, John Tianci; Kittrell, Carter; La, Nghi; Eddy, Lucas; Scotland, Phelecia; Cheng, Yi; Xu, Shichen; Li, Bowen; Tomson, Mason B.; Han, Yimo; Yakobson, Boris I.; Tour, James M.; Welch Institute for Advanced Materials; NanoCarbon Center; Applied Physics Program; Smalley-Curl Institute
    The staggering accumulation of end-of-life lithium-ion batteries (LIBs) and the growing scarcity of battery metal sources have triggered an urgent call for an effective recycling strategy. However, it is challenging to reclaim these metals with both high efficiency and low environmental footprint. We use here a pulsed dc flash Joule heating (FJH) strategy that heats the black mass, the combined anode and cathode, to >2100 kelvin within seconds, leading to ~1000-fold increase in subsequent leaching kinetics. There are high recovery yields of all the battery metals, regardless of their chemistries, using even diluted acids like 0.01 M HCl, thereby lessening the secondary waste stream. The ultrafast high temperature achieves thermal decomposition of the passivated solid electrolyte interphase and valence state reduction of the hard-to-dissolve metal compounds while mitigating diffusional loss of volatile metals. Life cycle analysis versus present recycling methods shows that FJH significantly reduces the environmental footprint of spent LIB processing while turning it into an economically attractive process.
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    Electrothermal mineralization of per- and polyfluoroalkyl substances for soil remediation
    (Springer Nature, 2024) Cheng, Yi; Deng, Bing; Scotland, Phelecia; Eddy, Lucas; Hassan, Arman; Wang, Bo; Silva, Karla J.; Li, Bowen; Wyss, Kevin M.; Ucak-Astarlioglu, Mine G.; Chen, Jinhang; Liu, Qiming; Si, Tengda; Xu, Shichen; Gao, Xiaodong; JeBailey, Khalil; Jana, Debadrita; Torres, Mark Albert; Wong, Michael S.; Yakobson, Boris I.; Griggs, Christopher; McCary, Matthew A.; Zhao, Yufeng; Tour, James M.
    Per- and polyfluoroalkyl substances (PFAS) are persistent and bioaccumulative pollutants that can easily accumulate in soil, posing a threat to environment and human health. Current PFAS degradation processes often suffer from low efficiency, high energy and water consumption, or lack of generality. Here, we develop a rapid electrothermal mineralization (REM) process to remediate PFAS-contaminated soil. With environmentally compatible biochar as the conductive additive, the soil temperature increases to >1000 °C within seconds by current pulse input, converting PFAS to calcium fluoride with inherent calcium compounds in soil. This process is applicable for remediating various PFAS contaminants in soil, with high removal efficiencies ( >99%) and mineralization ratios ( >90%). While retaining soil particle size, composition, water infiltration rate, and cation exchange capacity, REM facilitates an increase of exchangeable nutrient supply and arthropod survival in soil, rendering it superior to the time-consuming calcination approach that severely degrades soil properties. REM is scaled up to remediate soil at two kilograms per batch and promising for large-scale, on-site soil remediation. Life-cycle assessment and techno-economic analysis demonstrate REM as an environmentally friendly and economic process, with a significant reduction of energy consumption, greenhouse gas emission, water consumption, and operation cost, when compared to existing soil remediation practices.
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    Flash Graphene Synthesis: Optimization, Scaling, and Thermodynamics
    (2023-11-09) Eddy, Lucas; Tour, James M
    Flash Joule heating has been widely used as an ultrafast, scalable, and versatile synthesis method, most prominently in the synthesis of flash graphene. Traditional methods of graphene synthesis involve purely chemical or thermal means and are far more energy-intensive and far less scalable than flash Joule heating. Herein, we demonstrate kilogram-scale flash graphene synthesis using an automated flash Joule heater. We implement a pulse width modulation system to improve graphene quality and uniformity while scaling up to larger batch sizes. We furthermore report evidence that the flash Joule heating synthesis of graphene is an electrothermal process in which the presence of charge and the resulting electric field inside the graphene precursor facilitates graphene synthesis by lowering the activation energy of the reaction. We present both through experiment and theory the thermodynamic values of the flash Joule heating transition from amorphous carbon feedstocks, to turbostratic graphene, to finally ordered graphene and graphite. We finally compare the energy, environmental, and monetary costs of flash Joule heating to other scalable methods for graphene production via life cycle and technoeconomic assessments.
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    High-temperature electrothermal remediation of multi-pollutants in soil
    (Springer Nature, 2023) Deng, Bing; Carter, Robert A.; Cheng, Yi; Liu, Yuan; Eddy, Lucas; Wyss, Kevin M.; Ucak-Astarlioglu, Mine G.; Luong, Duy Xuan; Gao, Xiaodong; JeBailey, Khalil; Kittrell, Carter; Xu, Shichen; Jana, Debadrita; Torres, Mark Albert; Braam, Janet; Tour, James M.; NanoCarbon Center and the Rice Advanced Materials Institute; Smalley-Curl Institute
    Soil contamination is an environmental issue due to increasing anthropogenic activities. Existing processes for soil remediation suffer from long treatment time and lack generality because of different sources, occurrences, and properties of pollutants. Here, we report a high-temperature electrothermal process for rapid, water-free remediation of multiple pollutants in soil. The temperature of contaminated soil with carbon additives ramps up to 1000 to 3000 °C as needed within seconds via pulsed direct current input, enabling the vaporization of heavy metals like Cd, Hg, Pb, Co, Ni, and Cu, and graphitization of persistent organic pollutants like polycyclic aromatic hydrocarbons. The rapid treatment retains soil mineral constituents while increases infiltration rate and exchangeable nutrient supply, leading to soil fertilization and improved germination rates. We propose strategies for upscaling and field applications. Techno-economic analysis indicates the process holds the potential for being more energy-efficient and cost-effective compared to soil washing or thermal desorption.