Person: Tong, Liuchuan
Loading...
Email Address
AA Acceptance Date
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
Tong
First Name
Liuchuan
Name
Tong, Liuchuan
15 results
Search Results
Now showing 1 - 10 of 15
Publication Flow Batteries: Alkaline Benzoquinone Aqueous Flow Battery for Large-Scale Storage of Electrical Energy(Wiley-Blackwell, 2018) Yang, Zhengjin; Tong, Liuchuan; Tabor, Daniel; Beh, Eugene S.; Goulet, Marc-Antoni; De Porcellinis, Diana; Aspuru-Guzik, Alan; Gordon, Roy; Aziz, MichaelWe introduce an aqueous flow battery based on low-cost, non-flammable, non-corrosive and Earth-abundant elements. During charging, electrons are stored in a concentrated water solution of 2,5-dihydroxy-1,4-benzoquinone (DHBQ), which rapidly receives electrons with inexpensive carbon electrodes without the assistance of any metal electro-catalyst. Electrons are withdrawn from a second water solution of a food additive, potassium ferrocyanide (K4Fe(CN)6). When these two solutions flow along opposite sides of a cation-conducting membrane, this flow battery delivers a cell potential of 1.21 V, a peak galvanic power density of 300 mW/cm2 and a coulombic efficiency exceeding 99%. Continuous cell cycling at 100 mA/cm2 shows a capacity retention rate of 99.76%/cycle over 150 cycles. Various molecular modifications involving substitution for hydrogens on the aryl ring were implemented to block decomposition by nucleophilic attack of hydroxide ions in solution. These modifications resulted in increased capacity retention rates of up to 99.962%/cycle over 400 consecutive cycles, accompanied by changes in voltage, solubility, kinetics and cell resistance. Quantum chemistry calculations of a large number of organic compounds predicted a number of related structures that should have even higher performance and stability. Flow batteries based on alkaline-soluble dihydroxybenzoquinones and derivatives are promising candidates for large-scale, stationary-storage of electrical energy.Publication UV-Vis Spectrophotometry of Quinone Flow Battery Electrolyte for in Situ Monitoring and Improved Electrochemical Modeling of Potential and Quinhydrone Formation(Royal Society of Chemistry (RSC), 2017) Tong, Liuchuan; Chen, Qing; Wong, Andrew; Gómez-Bombarelli, Rafael; Aspuru-Guzik, Alan; Gordon, Roy; Aziz, MichaelQuinone-based aqueous flow batteries provide a potential opportunity for large-scale, low-cost energy storage due to their composition from earth abundant elements, high aqueous solubility, reversible redox kinetics and their chemical tunability such as reduction potential. In an operating flow battery utilizing 9,10-anthraquinone-2,7-disulfonic acid, the aggregation of an oxidized quinone and a reduced hydroquinone to form a quinhydrone dimer causes significant variations from ideal solution behavior and of optical absorption from the Beer-Lambert law. We utilize in-situ UV-Vis spectrophotometry to establish (a), quinone, hydroquinone and quinhydrone molar attenuation profiles and (b), an equilibrium constant for formation of the quinhydrone dimer (KQHQ) ~ 80 M-1. We use the molar optical attenuation profiles to identify the total molecular concentration and state of charge at arbitrary mixtures of quinone and hydroquinone. We report density functional theory calculations to support the quinhydrone UV-Vis measurements and to provide insight into the dimerization conformations. We instrument a quinone-bromine flow battery with a Pd-H reference electrode in order to demonstrate how complexation in both the negative (quinone) and positive (bromine) electrolytes directly impacts measured half-cell and full-cell voltages. This work shows how accounting for electrolyte complexation improves the accuracy of electrochemical modeling of flow battery electrolytes.Publication Quinone electrochemistry in acidic and alkaline solutions and its application in large scale energy storage(2015) Gerhardt, Michael; Lin, Kaixiang; Chen, Qing; Marshak, Michael; Tong, Liuchuan; Gordon, Roy; Aziz, MichaelPublication Alkaline quinone flow battery(American Association for the Advancement of Science (AAAS), 2015) Lin, Kaixiang; Chen, Qing; Gerhardt, Michael; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro; Hardee, D.; Gordon, Roy; Aziz, Michael; Marshak, MichaelStorage 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.Publication A redox-flow battery with an alloxazine-based organic electrolyte(Springer Nature, 2016) Lin, Kaixiang; Gómez-Bombarelli, Rafael; Beh, Eugene; Tong, Liuchuan; Chen, Qing; Valle, Alvaro; Aspuru-Guzik, Alan; Aziz, Michael; Gordon, RoyRedox-flow batteries (RFBs) can store large amounts of electrical energy from variable sources, such as solar and wind. Recently, redox-active organic molecules in aqueous RFBs have drawn substantial attention due to their rapid kinetics and low membrane crossover rates. Drawing inspiration from nature, here we report a high-performance aqueous RFB utilizing an organic redox compound, alloxazine, which is a tautomer of the isoalloxazine backbone of vitamin B2. It can be synthesized in high yield at room temperature by single-step coupling of inexpensive o-phenylenediamine derivatives and alloxan. The highly alkaline-soluble alloxazine 7/8-carboxylic acid produces a RFB exhibiting open-circuit voltage approaching 1.2 V and current efficiency and capacity retention exceeding 99.7% and 99.98% per cycle, respectively. Theoretical studies indicate that structural modification of alloxazine with electron-donating groups should allow further increases in battery voltage. As an aza-aromatic molecule that undergoes reversible redox cycling in aqueous electrolyte, alloxazine represents a class of radical-free redox-active organics for use in large-scale energy storage.Publication Comparison of Capacity Retention Rates During Cycling of Quinone-Bromide Flow Batteries(Cambridge University Press (CUP), 2016) Gerhardt, Michael; Beh, Eugene; Tong, Liuchuan; Gordon, Roy; Aziz, MichaelWe use cyclic charge-discharge experiments to evaluate the capacity retention rates of two quinone-bromide flow batteries (QBFBs). These aqueous QBFBs use a negative electrolyte containing either anthraquinone-2,7-disulfonic acid (AQDS) or anthraquinone-2-sulfonic acid (AQS) dissolved in sulfuric acid, and a positive electrolyte containing bromine and hydrobromic acid. We find that the AQS cell exhibits a significantly lower capacity retention rate than the AQDS cell. The observed AQS capacity fade is corroborated by NMR evidence that suggests the formation of hydroxylated products in the electrolyte in place of AQS. We further cycle the AQDS cell and observe a capacity fade rate extrapolating to 30% loss of active species after 5000 cycles. After about 180 cycles, bromine crossover leads to sufficient electrolyte imbalance to accelerate the capacity fade rate, indicating that the actual realization of long cycle life will require bromine rebalancing or a membrane less permeable than Nafion® to molecular bromine.Publication A Biocompatible Alkene Hydrogenation Merges Organic Synthesis with Microbial Metabolism(Wiley-Blackwell, 2014) Sirasani, Gopal; Tong, Liuchuan; Balskus, EmilyOrganic chemists and metabolic engineers use largely orthogonal technologies to construct essential small molecules like pharmaceuticals and commodity chemicals. While chemists have leveraged the unique capabilities of biological catalysts for small molecule production, metabolic engineers have not likewise integrated reactions from organic synthesis with the metabolism of living organisms. Here we report a method for alkene hydrogenation that utilizes a palladium catalyst and hydrogen gas generated directly by a living microorganism. This biocompatible transformation, which requires both catalyst and microbe and can be used on a preparative scale, represents a new strategy for chemical synthesis that combines organic chemistry and metabolic engineering.Publication Extending the Lifetime of Organic Flow Batteries via Redox State Management(American Chemical Society (ACS), 2019-04-26) Goulet, Marc-Antoni; Tong, Liuchuan; Pollack, Daniel; Tabor, Daniel P.; Odom, Susan A.; Aspuru-Guzik, Alán; Kwan, Eugene; Gordon, Roy; Aziz, MichaelRedox flow batteries based on quinone-bearing aqueous electrolytes have emerged as promising systems for energy storage from intermittent renewable sources. The lifetime of these batteries is limited by quinone stability. Here, we confirm that 2,6-dihydroxyanthrahydroquinone tends to form an anthrone intermediate that is vulnerable to subsequent irreversible dimerization. We demonstrate quantitatively that this decomposition pathway is responsible for the loss of battery capacity. Computational studies indicate that the driving force for anthrone formation is greater for anthraquinones with lower reduction potentials. We show that the decomposition can be substantially mitigated. We demonstrate that conditions minimizing anthrone formation and avoiding anthrone dimerization slow the capacity loss rate by over an order of magnitude. We anticipate that this mitigation strategy readily extends to other anthraquinone-based flow batteries and is thus an important step toward realizing renewable electricity storage through long-lived organic flow batteries.Publication A Long-Lifetime All-Organic Aqueous Flow Battery Utilizing TMAP-TEMPO Radical(Elsevier BV, 2019-07) Liu, Yahua; Goulet, Marc-Antoni; Tong, Liuchuan; Liu, Yazhi; Ji, Yunlong; Wu, Liang; Gordon, Roy; Aziz, Michael; Yang, Zhengjin; Xu, TongwenThe massive-scale integration of renewable electricity into the power grid is impeded by its intrinsic intermittency. The aqueous organic redox flow battery (AORFB) rises as a potential storage solution; however, the choice of positive electrolytes is limited, and the aqueous-soluble organic positive redox-active species reported to date have short lifetimes. Here we report a stable organic molecule for the positive terminal, 4-[3-(trimethylammonio)propoxy]-2,2,6,6- tetramethylpiperidine-1-oxyl (TMAP-TEMPO) chloride, exhibiting high (4.62 M) aqueous solubility. When operated in a practical AORFB against a negative electrolyte comprising BTMAP-viologen at neutral pH, the flow cell displayed an open-circuit voltage of 1.1 Volts and a coulombic efficiency of >99.73%. The capacity retention rate is among the highest of all-organic AORFBs reported to date, at 99.993% per cycle over 1000 consecutive cycles; the temporal capacity fade rate of 0.026% per hour is independent of concentration.Publication A Water-Miscible Quinone Flow Battery with High Volumetric Capacity and Energy Density(American Chemical Society (ACS), 2019) Jin, Shijian; Jing, Yan; Kwabi, David; Ji, Yunlong; Tong, Liuchuan; De Porcellinis, Diana; Goulet, Marc-Antoni; Pollack, Daniel A.; Gordon, Roy; Aziz, MichaelA water-miscible anthraquinone with polyethylene glycol (PEG)-based solubilizing groups is introduced as the redox-active molecule in a negative electrolyte (negolyte) for aqueous redox flow batteries, exhibiting the highest volumetric capacity among aqueous organic negolytes. We synthesized and screened a series of PEG-substituted anthraquinones (PEGAQs) and carefully studied one of its isomers, namely 1,8-bis(2-(2-(2- hydroxyethoxy)ethoxy)ethoxy)anthracene-9,10-dione (AQ-1,8-3E-OH), which has high electrochemical reversibility and is completely miscible in water of any pH. A negolyte containing 1.5 M AQ-1,8-3E-OH, when paired with a ferrocyanide-based positive electrolyte across an inexpensive, non-fluorinated permselective polymer membrane at pH 7, exhibits an open-circuit potential of 1.0 V, a volumetric capacity of 80.4 Ah/L, and an energy density of 25.2 Wh/L.