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Jeffrey A. Kowalski

Other affiliations: Argonne National Laboratory
Bio: Jeffrey A. Kowalski is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Materials science & Flow battery. The author has an hindex of 13, co-authored 18 publications receiving 1098 citations. Previous affiliations of Jeffrey A. Kowalski include Argonne National Laboratory.

Papers
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TL;DR: In this article, the authors investigated electrochemical systems capable of economically storing energy for hours and presented an analysis of the relationships among technological performance characteristics, component cost factors, and system price for established and conceptual aqueous and nonaqueous batteries.
Abstract: Energy storage is increasingly seen as a valuable asset for electricity grids composed of high fractions of intermittent sources, such as wind power or, in developing economies, unreliable generation and transmission services However, the potential of batteries to meet the stringent cost and durability requirements for grid applications is largely unquantified We investigate electrochemical systems capable of economically storing energy for hours and present an analysis of the relationships among technological performance characteristics, component cost factors, and system price for established and conceptual aqueous and nonaqueous batteries We identified potential advantages of nonaqueous flow batteries over those based on aqueous electrolytes; however, new challenging constraints burden the nonaqueous approach, including the solubility of the active material in the electrolyte Requirements in harmony with economically effective energy storage are derived for aqueous and nonaqueous systems The attributes of flow batteries are compared to those of aqueous and nonaqueous enclosed and hybrid (semi-flow) batteries Flow batteries are a promising technology for reaching these challenging energy storage targets owing to their independent power and energy scaling, reliance on facile and reversible reactants, and potentially simpler manufacture as compared to established enclosed batteries such as lead–acid or lithium-ion

532 citations

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TL;DR: In this article, the rational design of organic molecules with flow cell engineering was combined to boost the performance of non-aqueous redox flow batteries (NAqRFBs) for grid energy storage, achieving a current density of 100 mA cm−2 with undetectable capacity fade over 100 cycles.
Abstract: Non-aqueous redox flow batteries (NAqRFBs) employing redox-active organic molecules show promise to meet requirements for grid energy storage. Here, we combine the rational design of organic molecules with flow cell engineering to boost NAqRFB performance. We synthesize two highly soluble phenothiazine derivatives, N-(2-methoxyethyl)phenothiazine (MEPT) and N-[2-(2-methoxyethoxy)ethyl]phenothiazine (MEEPT), via a one-step synthesis from inexpensive precursors. Synthesis and isolation of the radical-cation salts permit UV-vis decay studies that illustrate the high stability of these open-shell species. Cyclic voltammetry and bulk electrolysis experiments reveal the promising electrochemical properties of MEPT and MEEPT under dilute conditions. A high performance non-aqueous flow cell, employing interdigitated flow fields and carbon paper electrodes, is engineered and demonstrated; polarization and impedance studies quantify the cell's low area-specific resistance (3.2–3.3 Ω cm2). We combine the most soluble derivative, MEEPT, and its tetrafluoroborate radical-cation salt in the flow cell for symmetric cycling, evincing a current density of 100 mA cm−2 with undetectable capacity fade over 100 cycles. This coincident high current density and capacity retention is unprecedented in NAqRFB literature.

176 citations

Journal ArticleDOI
TL;DR: In this article, a new heterocyclic organic anolyte molecule, 2,1,3-benzothiadiazole, has been reported, which has high solubility, a low redox potential, and fast electrochemical kinetics.
Abstract: Redox-active organic materials (ROMs) have shown great promise for redox flow battery applications but generally encounter limited cycling efficiency and stability at relevant redox material concentrations in nonaqueous systems. Here we report a new heterocyclic organic anolyte molecule, 2,1,3-benzothiadiazole, that has high solubility, a low redox potential, and fast electrochemical kinetics. Coupling it with a benchmark catholyte ROM, the nonaqueous organic flow battery demonstrated significant improvement in cyclable redox material concentrations and cell efficiencies compared to the state-of-the-art nonaqueous systems. Especially, this system produced exceeding cyclability with relatively stable efficiencies and capacities at high ROM concentrations (>0.5 M), which is ascribed to the highly delocalized charge densities in the radical anions of 2,1,3-benzothiadiazole, leading to good chemical stability. This material development represents significant progress toward promising next-generation energy st...

161 citations

Journal ArticleDOI
Abstract: Cost-effective electrochemical energy storage will play a critical role as society transitions to a sustainable energy economy. Nonaqueous flow batteries employing redox active organic molecules are an emerging energy storage concept. A key advantage of this device over the more established aqueous flow battery is the promise for higher cell potentials (>3 V), enabled by the larger electrochemical stability windows of nonaqueous electrolytes. Additionally, nonaqueous flow batteries could leverage new redox couples that are incompatible with aqueous electrolytes due to low solubility, chemical reactivity, and redox potentials outside of the aqueous stability window. Taking advantage of these characteristics may lead to higher energy densities, smaller system footprints, and lower costs. This mini review summarizes recent developments in all-organic nonaqueous chemistries with a focus on tailoring organic molecules for improved physical and electrochemical properties. Key opportunities and challenges in the science and engineering of these devices are presented with a goal of meeting stringent grid cost targets.

92 citations

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TL;DR: In this article, a simple modification of N-ethylphenothiazine, which is only stable as a radical cation (not as a dication), was reported, and it was shown that introducing electron-donating methoxy groups to nitrogen leads to dramatically improved stability of the doubly oxidized (dication) state.
Abstract: Stable electron-donating organic compounds are of interest for numerous applications that require reversible electron-transfer reactions. Although many organic compounds are stable one-electron donors, removing a second electron from a small molecule to form its dication usually leads to rapid decomposition. For cost-effective electrochemical energy storage utilizing organic charge-storage species, the creation of high-capacity materials requires stabilizing more charge whilst keeping molecular weights low. Here we report the simple modification of N-ethylphenothiazine, which is only stable as a radical cation (not as a dication), and demonstrate that introducing electron-donating methoxy groups para to nitrogen leads to dramatically improved stability of the doubly oxidized (dication) state. Our results reveal that this derivative is more stable than an analogous compound with substituents that do not allow for further charge delocalization, rendering it a promising scaffold for developing atom-efficient, two-electron donors.

92 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI

906 citations

Journal ArticleDOI
TL;DR: This Review will describe key advances in both more sustainable chemistries and operando techniques, along with some of the remaining challenges and possible solutions, as the authors personally perceive them.
Abstract: The development of improved rechargeable batteries represents a major technological challenge for this new century, as batteries constitute the limiting components in the shift from petrol (gasoline) powered to electric vehicles, while also enabling the use of more renewable energy on the grid. To minimize the ecological implications associated with their wider use, we must integrate sustainability of battery materials into our research endeavours, choosing chemistries that have a minimum footprint in nature and that are more readily recycled or integrated into a full circular economy. Sustainability and cost concerns require that we greatly increase the battery lifetime and consider second lives for batteries. As part of this, we must monitor the state of health of batteries continuously during operation to minimize their degradation. It is thus important to push the frontiers of operando techniques to monitor increasingly complex processes. In this Review, we will describe key advances in both more sustainable chemistries and operando techniques, along with some of the remaining challenges and possible solutions, as we personally perceive them.

855 citations

Journal ArticleDOI
TL;DR: In this paper, the authors analyze data on 11 storage technologies, constructing experience curves to project future prices, and explore feasiblity of these technologies for decarbonizing personal transport and enabling highly renewable electricity systems.
Abstract: Electrical energy storage is expected to be important for decarbonizing personal transport and enabling highly renewable electricity systems. This study analyses data on 11 storage technologies, constructing experience curves to project future prices, and explores feasibl…

786 citations

Journal ArticleDOI
25 Sep 2015-Science
TL;DR: An alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments is reported, potentially enabling cost-effective stationary storage of renewable energy.
Abstract: Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy.

767 citations