Effect of cathode thickness on the performance of planar Na-NiCl₂ battery

Lu, Xiaochuan,Chang, Hee Jung,Bonnett, Jeff F.,Canfield, Nathan L.,Jung, Keeyoung,Sprenkle, Vincent L.,Li, Guosheng Elsevier 2017 Journal of Power Sources Vol.365 No.-

<P><B>Abstract</B></P> <P>Na-beta alumina batteries (NBBs) are one of the most promising technologies for renewable energy storage and grid applications. Commercial NBBs are typically constructed in tubular designs, primarily because of their ease of sealing. However, planar designs are considered superior to tubular counterparts in terms of power output, cell packing, ease of assembly, and thermal management. In this paper, the performance of planar NBBs has been evaluated at an intermediate temperature. In particular, planar Na-NiCl<SUB>2</SUB> cells with different cathode loadings and thicknesses have been studied at 190 °C. The effects of the cathode thickness, charging current, and discharging power output on the cell capacity and resistance have been investigated. More than 60% of theoretical cell capacity was retained with constant discharging power levels of 200, 175, and 100 mW/cm<SUP>2</SUP> for 1x, 2x, and 3x cathode loadings, respectively. The cell resistance with 1x and 2x cathode loadings was dominated by ohmic resistance with discharging currents up to 105 mA/cm<SUP>2</SUP>, while for 3x cathode loading, it was primarily dominated by ohmic resistance with currents less than 66.67 mA/cm<SUP>2</SUP> and by polarization resistance above 66.67 mA/cm<SUP>2</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Performance of planar Na-NiCl<SUB>2</SUB> cells was primarily limited by the charging current. </LI> <LI> Cells with 1x and 2x cathodes were dominated by ohmic resistance up to 105 mA/cm<SUP>2</SUP>. </LI> <LI> The cell with 3x cathode retained 27% of the capacity at a power output of 200 mW/cm<SUP>2</SUP>. </LI> </UL> </P>

Effects of fabrication conditions on mechanical properties and microstructure of duplex β''-Al₂O₃ solid electrolyte

Canfield, N.L.,Kim, J.Y.,Bonnett, J.F.,Pearson, R.L.,Sprenkle, V.L.,Jung, K. Elsevier 2015 Materials science and engineering B. Advanced Func Vol.197 No.-

Na-beta batteries are an attractive technology as a large-scale electrical energy storage for grid applications. However, additional improvements in performance and cost are needed for wide market penetration. To improve cell performance by minimizing polarizations, reduction of electrolyte thickness was attempted using a duplex structure consisting of a thin dense electrolyte layer and a porous support layer. In this paper, the effects of sintering conditions, dense electrolyte thickness, and cell orientation on the flexural strength of duplex BASEs fabricated using a vapor phase approach were investigated. It is shown that sintering at temperatures between 1500 and 1550<SUP>o</SUP>C results in fine grained microstructures and the highest flexural strength after conversion. Increasing thickness of the dense electrolyte has a small impact on flexural strength, while the orientation of load such that the dense electrolyte is in tension instead of compression has major effects on strength for samples with a well-sintered dense electrolyte.

Development of intermediate temperature sodium nickel chloride rechargeable batteries using conventional polymer sealing technologies

Chang, Hee Jung,Lu, Xiaochuan,Bonnett, Jeff F.,Canfield, Nathan L.,Son, Sori,Park, Yoon-Cheol,Jung, Keeyoung,Sprenkle, Vincent L.,Li, Guosheng Elsevier 2017 Journal of Power Sources Vol.348 No.-

<P><B>Abstract</B></P> <P>Developing advanced and reliable electrical energy storage systems is critical to fulfill global energy demands and stimulate the growth of renewable energy resources. Sodium metal halide batteries have been under serious consideration as a low cost alternative energy storage device for stationary energy storage systems. Yet, there are number of challenges to overcome for the successful market penetration, such as high operating temperature and hermetic sealing of batteries that trigger an expensive manufacturing process. Here we demonstrate simple, economical and practical sealing technologies for Na-NiCl<SUB>2</SUB> batteries operated at an intermediate temperature of 190 °C. Conventional polymers are implemented in planar Na-NiCl<SUB>2</SUB> batteries after a prescreening test, and their excellent compatibilities and durability are demonstrated by a stable performance of Na-NiCl<SUB>2</SUB> battery for more than 300 cycles. The sealing methods developed in this work will be highly beneficial and feasible for prolonging battery cycle life and reducing manufacturing cost for Na-based batteries at elevated temperatures (<200 °C).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Conventional polymers were adopted as sealing materials for Na-NiCl<SUB>2</SUB> batteries. </LI> <LI> Selected polymers showed excellent compatibility with sodium and melts at 190 °C. </LI> <LI> Batteries with polymer seals showed stable performances over 300 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

ITER TBM Program and associated system engineering

Giancarli, Luciano M.,Ahn, Mu-Young,Bonnett, Ian,Boyer, Christophe,Chaudhuri, Paritosh,Davis, William,Dell’Orco, Giovanni,Iseli, Markus,Michling, Robert,Neviere, Jean-Christophe,Pascal, Romain,Poitevi Elsevier 2018 Fusion engineering and design Vol.136 No.2

<P><B>Abstract</B></P> <P>Six Test Blanket Systems (TBS) will be installed and operated in ITER in the framework of the ITER Test Blanket Module (TBM) Program. After a short description of each TBS and of the main operating parameters, this paper gives the main features of the various TBSs sub-systems, in particular, the cooling systems (helium, water and/or lithium-lead), the tritium system for extracting the tritium from the breeder, the coolant purification system, the tritium accountancy system, and several instrumentation & control systems. This paper addresses also the main services that are needed to operate a TBS such as the secondary water cooling system, the chilled water system to cool the helium circulators, the liquid and gaseous nitrogen used in the tritium extraction process, the compressed air needed to operate the various valves present on the circuits, and the electrical power supply for all the active electrical components such as pumps, circulators and heaters. Other important aspects are the required interfaces with other ITER plant systems such as those involving air and process gas detritiation, power supply, radiological and environmental monitoring, remote handling, measurements, and services.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The ITER TBM Program plans to test DEMO-relevant tritium breeding blanket systems. </LI> <LI> Each TBS is formed by various sub-systems with different functions and technologies. </LI> <LI> For each TBS sub-system, description of its functions and its main components. </LI> <LI> Identification of the ITER services required for operating each TBS sub-system. </LI> <LI> Helium and water coolant systems, tritium extraction systems, Pb-16Li systems, I&C. </LI> </UL> </P>

A duplex β″-Al₂O₃ solid electrolyte consisting of a thin dense layer and a porous substrate

Kim, Jin Y.,Canfield, Nathan L.,Bonnett, Jeff F.,Sprenkle, Vincent L.,Jung, Keeyoung,Hong, Inchul Elsevier 2015 Solid state ionics Vol.278 No.-

<P><B>Abstract</B></P> <P>To improve the performance of Na-beta batteries at intermediate temperatures (≤200°C) where much improved cyclability and reduced degradation can be achieved, there is a need to lower the resistance/polarization originated from β″-Al<SUB>2</SUB>O<SUB>3</SUB> solid electrolyte (BASE) while maintaining its good strength. In this paper, the concept of a duplex BASE consisting of a thin dense electrolyte and a porous support was proposed as a solution to achieve low area-specific resistance (ASR) with good mechanical strength supported by the porous substrate. The effects of various factors including porosity, composition, and homogeneity of ingredients on the flexural strength of duplex BASEs were examined. In summary, lower porosity, higher YSZ content in the structure, and attrition milling of raw powders resulted in improved strength. The ASR measurement exhibited that the resistance of duplex BASEs was mainly originated from a dense layer. Overall, the maximum strength of 260MPa and the ASR value of 0.31Ωcm<SUP>2</SUP> (at 350°C) was achieved from a duplex BASE consisting of a 50μm thick dense layer (Al<SUB>2</SUB>O<SUB>3</SUB>:YSZ=7:3 in volume) and a 500μm thick porous support (Al<SUB>2</SUB>O<SUB>3</SUB>:YSZ=4:6 in volume with 19% open porosity). The effects of various factors on the properties of duplex BASEs will be discussed in detail.</P> <P><B>Highlights</B></P> <P> <UL> <LI> As a method to lower the ASR, the concept of duplex BASEs is presented. </LI> <LI> A duplex BASEs consists of a thin dense β″-alumina layer and a mechanically strong porous support. </LI> <LI> Processing factors including conversion, porosity, composition, and homogeneity influence the strength of a duplex BASE. </LI> <LI> The minimum ASR value of 0.31Ωcm<SUP>2</SUP> was achieved at 350°C with decent strength of 260MPa. </LI> </UL> </P>

Cosmic shear measurements with Dark Energy Survey Science Verification data

Becker, M. R.,Troxel, M. A.,MacCrann, N.,Krause, E.,Eifler, T. F.,Friedrich, O.,Nicola, A.,Refregier, A.,Amara, A.,Bacon, D.,Bernstein, G. M.,Bonnett, C.,Bridle, S. L.,Busha, M. T.,Chang, C.,Dodelson, American Physical Society 2016 Physical Review D Vol.94 No.2

<P>We present measurements of weak gravitational lensing cosmic shear two-point statistics using Dark Energy Survey Science Verification data. We demonstrate that our results are robust to the choice of shear measurement pipeline, either NGMIX or IM3SHAPE, and robust to the choice of two-point statistic, including both real and Fourier-space statistics. Our results pass a suite of null tests including tests for B-mode contamination and direct tests for any dependence of the two-point functions on a set of 16 observing conditions and galaxy properties, such as seeing, airmass, galaxy color, galaxy magnitude, etc. We furthermore use a large suite of simulations to compute the covariance matrix of the cosmic shear measurements and assign statistical significance to our null tests. We find that our covariance matrix is consistent with the halo model prediction, indicating that it has the appropriate level of halo sample variance. We compare the same jackknife procedure applied to the data and the simulations in order to search for additional sources of noise not captured by the simulations. We find no statistically significant extra sources of noise in the data. The overall detection significance with tomography for our highest source density catalog is 9.7 sigma. Cosmological constraints from the measurements in this work are presented in a companion paper.</P>