Browsing by Author "Chen, Weiyin"

Now showing 1 - 6 of 6
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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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    Flash joule heating synthesis method and compositions thereof
    (2024-08-06) Tour, James Mitchell; Luong X, Duy; Kittrell, Wilbur Carter; Chen, Weiyin; Rice University; United States Patent and Trademark Office
    Methods for the synthesis of graphene, and more particularly the method of synthesizing graphene by flash Joule heating (FJH). Such methods can be used to synthesize turbostratic graphene (including low-defect turbostratic graphene) in bulk quantities. Such methods can further be used to synthesize composite materials and 2D materials.
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    Joule heating routes for nanomaterial syntheses and surface modification for nanoscale applications
    (2022-12-02) Chen, Weiyin; Tour, James M.
    It is widely known that chemical properties of nanomaterials are structure- and composition-dependent. Through the direct control of synthetic methods and experimental conditions, material-specific features, like constituents, dimensionalities, and arrangement of the atoms within the materials, can be engineered, and the manipulation of desired chemical properties can be achieved. Compared with traditional materials preparation and processing methods, a new electrothermal strategy can achieve selective Joule heating of the reactants to a high temperature (>3000 K) with rapid heating and cooling rates (>104 K s-1), enabling the kinetic control of chemical reactions and the formation of hitherto hard-to-access metastable nanomaterials. To this end, my thesis covers research on direct electrothermal methods to synthesize ~30 different thermodynamically metastable nanomaterials, followed by the exploration of phase transformations and evolution using experiments and simulations. These nanomaterials show new mechanical, optical, and electronic properties, distinct from their more thermodynamically stable counterparts. This thesis begins with the syntheses of carbonaceous nanomaterials using the rapid high temperature electrothermal method. In Chapter 1, 8 different types of heteroatom-doped turbostratic graphene were synthesized and compared with commercial graphite and undoped turbostratic graphene, demonstrating that doped turbostratic graphene had better dispersibility and electrocatalytic oxygen reduction performance. In Chapter 2, the detailed spectroscopic and microscopic studies were provided, related to the formation of fluorinated nanodiamonds and subsequent reaction time-dependent phase evolution to fluorinated graphene and concentric carbon. Non-carbonaceous nanomaterials can also be synthesized or processed, demonstrating the universality of the electrothermal method. The preparation of turbostratic boron nitride, various boron-carbon-nitrogen ternary compounds and 1T-phase transition metal dichalcogenides were illustrated in Chapter 3 and Chapter 4. The rapid Joule heating methods to recycle the anode, cathode, and their mixtures were further discussed in Chapters 5-7. In addition, the utilization of above nanomaterials as the additives to fabricate the coating for modifying the surface wettability was demonstrated in Chapter 8. The artificial coating of the reactive metals and current collectors to improve the electrochemical stability in the rechargeable metal batteries were discussed in Chapter 9 and Chapter 10, reflecting the promising applications of these nanomaterials for surface modification.
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    Nondestructive flash cathode recycling
    (Springer Nature, 2024) Chen, Weiyin; Cheng, Yi; Chen, Jinhang; Bets, Ksenia V.; Salvatierra, Rodrigo V.; Ge, Chang; Li, John Tianci; Luong, Duy Xuan; Kittrell, Carter; Wang, Zicheng; McHugh, Emily A.; Gao, Guanhui; Deng, Bing; Han, Yimo; Yakobson, Boris I.; Tour, James M.; Applied Physics Program;Smalley-Curl Institute;NanoCarbon Center;Rice Advanced Materials Institute
    Effective recycling of end-of-life Li-ion batteries (LIBs) is essential due to continuous accumulation of battery waste and gradual depletion of battery metal resources. The present closed-loop solutions include destructive conversion to metal compounds, by destroying the entire three-dimensional morphology of the cathode through continuous thermal treatment or harsh wet extraction methods, and direct regeneration by lithium replenishment. Here, we report a solvent- and water-free flash Joule heating (FJH) method combined with magnetic separation to restore fresh cathodes from waste cathodes, followed by solid-state relithiation. The entire process is called flash recycling. This FJH method exhibits the merits of milliseconds of duration and high battery metal recovery yields of ~98%. After FJH, the cathodes reveal intact core structures with hierarchical features, implying the feasibility of their reconstituting into new cathodes. Relithiated cathodes are further used in LIBs, and show good electrochemical performance, comparable to new commercial counterparts. Life-cycle-analysis highlights that flash recycling has higher environmental and economic benefits over traditional destructive recycling processes.
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    Oxidized Activated Charcoal Nanozymes: Synthesis, and Optimization for In Vitro and In Vivo Bioactivity for Traumatic Brain Injury
    (Wiley, 2024) McHugh, Emily A.; Liopo, Anton V.; Mendoza, Kimberly; Robertson, Claudia S.; Wu, Gang; Wang, Zhe; Chen, Weiyin; Beckham, Jacob L.; Derry, Paul J.; Kent, Thomas A.; Tour, James M.; Smalley-Curl Institute;NanoCarbon Center;Welch Institute for Advanced Materials
    Carbon-based superoxide dismutase (SOD) mimetic nanozymes have recently been employed as promising antioxidant nanotherapeutics due to their distinct properties. The structural features responsible for the efficacy of these nanomaterials as antioxidants are, however, poorly understood. Here, the process–structure–property–performance properties of coconut-derived oxidized activated charcoal (cOAC) nano-SOD mimetics are studied by analyzing how modifications to the nanomaterial's synthesis impact the size, as well as the elemental and electrochemical properties of the particles. These properties are then correlated to the in vitro antioxidant bioactivity of poly(ethylene glycol)-functionalized cOACs (PEG-cOAC). Chemical oxidative treatment methods that afford smaller, more homogeneous cOAC nanoparticles with higher levels of quinone functionalization show enhanced protection against oxidative damage in bEnd.3 murine endothelioma cells. In an in vivo rat model of mild traumatic brain injury (mTBI) and oxidative vascular injury, PEG-cOACs restore cerebral perfusion rapidly to the same extent as the former nanotube-derived PEG-hydrophilic carbon clusters (PEG-HCCs) with a single intravenous injection. These findings provide a deeper understanding of how carbon nanozyme syntheses can be tailored for improved antioxidant bioactivity, and set the stage for translation of medical applications.
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    Phase controlled synthesis of transition metal carbide nanocrystals by ultrafast flash Joule heating
    (Springer Nature, 2022) Deng, Bing; Wang, Zhe; Chen, Weiyin; Li, John Tianci; Luong, Duy Xuan; Carter, Robert A.; Gao, Guanhui; Yakobson, Boris I.; Zhao, Yufeng; Tour, James M.; Smalley-Curl Institute; NanoCarbon Center and the Welch Institute for Advanced Materials
    Nanoscale carbides enhance ultra-strong ceramics and show activity as high-performance catalysts. Traditional lengthy carburization methods for carbide syntheses usually result in coked surface, large particle size, and uncontrolled phase. Here, a flash Joule heating process is developed for ultrafast synthesis of carbide nanocrystals within 1 s. Various interstitial transition metal carbides (TiC, ZrC, HfC, VC, NbC, TaC, Cr2C3, MoC, and W2C) and covalent carbides (B4C and SiC) are produced using low-cost precursors. By controlling pulse voltages, phase-pure molybdenum carbides including β-Mo2C and metastable α-MoC1-x and η-MoC1-x are selectively synthesized, demonstrating the excellent phase engineering ability of the flash Joule heating by broadly tunable energy input that can exceed 3000 K coupled with kinetically controlled ultrafast cooling (>104 K s−1). Theoretical calculation reveals carbon vacancies as the driving factor for topotactic transition of carbide phases. The phase-dependent hydrogen evolution capability of molybdenum carbides is investigated with β-Mo2C showing the best performance.