bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alignment of Conductive Additive in Li-Ion Battery Electrodes through Use of Electric Fields
Authors: Clemens Noah , Wheeler Dean , Mazzeo Brian 
Published: February 2020

Currently, Li-ion battery electrodes are produced by coating onto the current collector a slurry composed of active particles, carbon black (CB), binder, and solvent. Coating is followed by drying, and calendering steps. This method creates a quasi-random distribution of CB particles throughout the battery electrode. The CB particles are intended to improve electronic pathways between active particles and the current collector.
By applying an electric field to the electrode slurry while it is drying, the carbon particles can be aligned or form chains in response to electric forces. These chains function as improved pathways for the electrons, reducing the impedance of the electrode. This has the potential to allow thicker electrodes, faster charging, or possibly a reduction in the required amount of CB additive.
In this talk, we discuss our use of flexible micro-probes [1] to both apply an electric field during drying and to assess the final conductivity of the dried film. Alternating electric current (AC) is used. The impedance of the samples dried with AC will be compared with of those of sample dried using conventional methods. We also explore the effects of different frequencies of AC on the resulting conductivity and discuss the plausibility of scaling this method of drying under electric fields to an industrially relevant process.
[1] Lanterman et al., J. Electrochem. Soc.
162, A2145-A2151 (2015).
(Invited) Structure of NMC Family Cathodes from Monte Carlo Simulation and NMR Spectroscopy
Authors: Harris Kristopher J. , Hurst Chelsey , Goward Gillian R. , Foster Jamie M. 
Published: February 2020

The cathode active material Li[Ni1/3Mn1/3Co1/3O2], NMC 111, is well known for its excellent cycling lifetime and capacity. It is also well known that varying the ratios of transition metals (TMs), Li atoms, and vacancies1 can provide capacity increases of up to 40 %, though at the expense of structural stability. Not only are these structural-breakdown pathways not understood, full models of even the pristine materials are not available because of the significant disorder. It seems apparent that better structural characterization tools are needed to understand these materials, and therefore may finally provide the key to unlocking their potential.
Here, we present a Monte-Carlo structure-solution method, using a Hamiltonian that is based on local electroneutrality [2]. The close-packed 2D TM sheet of the NMC family is partitioned according to valence-bonding principles and a state of local charge balance—for the TM atoms with respect to the neighboring (fixed) 2D oxygen sheet—is sought. This simple Hamiltonian allows rapid, yet realistic, sampling of the configuration space of the large sheets (up to 10,000 TM atoms) necessary to properly capture the (often) complex arrangements.
The predicted structural models are verified as accurate using 7Li NMR spectroscopy. The unpaired electrons of the TM atoms generate large paramagnetic chemical shifts in the neighboring Li atoms [3]. The 7Li spectra are therefore sensitive to the identity of the 12 TM atoms neighboring each Li: 6 in the TM sheet above, 6 in the sheet below [3]. Notably, the orientation dependence of this effect is not a hindrance when using 7Li MATPASS NMR spectroscopy under 60 kHz MAS [4].
A series of samples with compositions Li[Ni
x
Mn
x
Co1-2x
O2] are investigated, where x = 2%, 10%, and 33%. In each case, structures generated by the Monte Carlo calculations are verified through an extremely accurate matching between predicted and experimental 7Li NMR spectra. Additionally, accurate 3D simulations of electrochemically charged versions of these samples, where transition-metal oxidation and delithiation occur, are presented.

Reference
s
:

[1] R. Shunmugasundaram, S. Arumugam, J.R. Dahn Chem. Mater. 25 (2015) 989.
[2] K.J. Harris et al. Chem. Mater. 29 (2017) 5550. [3] D. Zeng et al. Chem. Mater. 19 (2007) 6277.
[4] I. Hung et al. J. Am. Chem. Soc. 134 (2012) 1898.

Figure 1
(Invited) Progress in Metal-Supported Solid Oxide Cells with Infiltrated Electrodes
Authors: Tucker Michael C , Dogdibegovic Emir , Shen Fengyu , Wang Ruofan , Lau Grace Y 
Published: February 2020

This talk will provide an overview of performance, durability, and applications of metal-supported solid oxide fuel cell and electrolysis cell technology developed at Lawrence Berkeley National Laboratory (LBNL). The unique LBNL symmetric cell architecture design, with thin zirconia ceramic backbones and electrolyte sandwiched between porous metal supports, offers a number of advantages over conventional all-ceramic cells, including low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. The metal-supported solid oxide cells achieve high performance at 700°C:
>1.5 W/cm2 with 3% humidified hydrogen fuel
>1.2 W/cm2 with internal reforming of ethanol fuel
>2.6 A/cm2 electrolysis current density at 1.3V and 50%steam/50% hydrogen
With infiltrated catalysts, there is a tradeoff between initial performance and long-term stability, as extremely high surface area promotes high electrochemical reaction rates, but also provides high surface energy leading to coarsening and facilitates Cr deposition. Recent approaches to mitigating catalyst coarsening and Cr deposition within the cathode include coatings to prevent Cr evaporation from the stainless steel components, and optimization of infiltrated catalyst processing to stabilize the microstructure during operation. The degradation rate has improved to 2.3% kh-1 in fuel cell mode, compatible with the requirements for electric vehicle range extenders. Electrolysis operation, however, results in higher degradation rate. Efforts to identify and mitigate the additional degradation mechanisms in electrolysis mode will be discussed. Scale-up from button cells to 50cm2 is ongoing, and highlights will be presented.
In addition to our long-standing development of zirconia-based metal-supported cells, recent exploratory effort has focused on compatibility between stainless steel metal supports and proton-conducting ceramics. Co-sintering of 400-series stainless steel and BZCY-type proton conductors presents a number of challenges, including: Ba evaporation in reducing atmosphere, over-densification of steel at the high temperatures (>1400°C) required for BZCY processing, and migration of Cr and Si from the steel support into the BZCY layers. Feasibility of new approaches to overcome these challenges will be discussed.
Distribution of Oxygen Partial Pressure in Multilayer Electrolytes: Explaining Degradation of Solid Oxide Electrolyzer Cells
Authors: Zhang Qian , Park Beom-Kyeong , Barnett Scott A , Voorhees Peter W 
Published: February 2020

It is found experimentally that solid oxide electrolyzer cells (SOECs) with mixed ionically and electronically conducting oxygen electrodes such as Lanthanum Strontium Cobalt Ferrite (LSCF) show much-reduced electrode fracture and degradation compared to cells with Sr-doped LaMnO3 (LSM): Yttria-stabilized Zirconia (YSZ) electrodes. In the former case, the cells have a Gadolinium doped Ceria (GDC) barrier sandwiched between the electrode and the YSZ electrolyte, i.e., there is a multi-layer electrolyte.
In order to investigate how different electrodes and the GDC barrier layer affect degradation phenomena and optimize the design of SOECs to achieve the desired long-term stability, a diffused interface model is proposed to investigate the distribution of oxygen partial pressure in the SOEC multi-layer electrolyte. Influence of operating condition, structures and properties of the electrolyte on the distribution of oxygen partial pressure are studied.
The model quantitatively predicts the conditions under which oxygen electrode fracture/delamination occurs, largely determined by the electrode overpotential given by the electrode polarization resistance. In addition, it is found that when a GDC barrier layer is present, there is a maximum in the oxygen pressure at the interface of the YSZ and GDC that can result in degradation or fracture. An analytical estimation on the oxygen partial pressure at the YSZ/GDC interface is obtained and shown to provide good agreement with numerical results. The predictions are also in accord with experimental observations of fracture or void formation near the GDC/YSZ interface. The results indicate that this peak pressure can be reduced by reducing the GDC layer thickness, use of a lower polarization resistance oxygen electrode, and by altering the electrolyte materials in order to affect their transport properties, e.g. reducing the Y doping level of YSZ to reduce the oxygen vacancy diffusivity. Changes in operating conditions, i.e., lowering the current density and increasing operating temperature can also reduce the peak pressure, and should thereby suppress the formation of pores or cracks at the YSZ/GDC interface.
Finally, inter-diffusion between YSZ and GDC during the electrolyte firing process can yield a low oxygen ion diffusivity zone at their interface. Our numerical simulation results show that this low oxygen ion diffusivity layer increases the maximum oxygen partial pressure at the GDC/YSZ interface, thereby exacerbating degradation.
Photoelectrochemical Supercontinuum Solar Light Zero Bias Hydrogen Generation with Membrane-Based Cells Designed for Decreasing Overall Water Electrolysis Voltage and Water Dissociation (23)
Authors: Sakamaki Kenji , Watanabe Ayana , Matsuda Honoka , Usui Sayuri , Sakashita Wakana , Kato Ryoko , Endo Haruka , Sato Masataka 
Published: February 2020

We have created a two-compartment cell (2CC) separated by a bipolar membrane (BPM1) sandwiched between through-holed electrodes (THEs) assembly (BPMTHEA-2CC) based on the Golden Role for sustainable water splitting derived from water dissociation (WD) with a dual chemical bias (CB).2 The BPMTHEA-2CC has distinguishing characteristics of integrated functionality of dualities, providing an infinite supply of active reaction species, H+ and OH-, from water with an opposite bidirectional charge separation under appropriate applied voltage conditions. We wish to suggest the feasibility of electrochemical water splitting (decomposition) with less than theoretical 1.23 V at RT using an anolyte (water or base)|OER active THE|BPM|HER active THE|catholyte (water or acid). We disprove the theory of water electrolysis established for hundreds of years with sustainable dual CBs. However, we still require external voltage for water electrolysis.
Instead of external voltage, we have harnessed solar energy by applying the TH n-type semiconductor photoanodes to BPMTHEA-2CC for a zero-bias photogalvanic cell. Anatase TH TiO2 was used for a model to demonstrate our concept. We succeeded in measuring photocurrent from distilled water with a response of optical shutter. The magnitude of the zero bias photocurrent is proportional to the magnitude of outer CB and illuminance intensity. TH Fe2O3 was prepared by the aqueous chemical growth method. Visible light zero bias photocurrent from distilled water was also observed in the TH Fe2O3 photogalvanic cell without any external voltage. Currently, our research efforts are focused on PEC zero bias hydrogen generation with harnessing supercontinuum solar light by designing optical tandem, wavelength multiplexing with BPMTHEA-2CC and Au plasmon-induced WD.
1) V. J. Frilette, J. Phys. Chem., 60, 435 (1956).
2) K. Sakamaki et al., 97th CSJ, 3A6-05 (2017), 68th ISE, Providence, USA, ise171503 (2017), The 22nd Top. Meeting of ISE, Tokyo, abs170627 (2018), 69th ISE, Bologna, Italy, ise183543 (2018).

Figure 1
(Invited) Harvesting Solar Energy in Near Infrared
Authors: Ma Dongling 
Published: February 2020

Broadening photon absorption into the near infrared (NIR) range represents a unique opportunity of improving the use of solar energy in various fields, including but not limited to solar fuel, solar cells and solar-enabled photo-degradation of pollutants. It is however challenging to realize this goal as most of traditional materials, such as dyes and semiconductors, do not absorb NIR lights efficiently. Recent advances of nanomaterials opens a new door in this research theme. In this talk, I will present some of our recent work on the design and synthesis of NIR absorbing materials, such as upconverting nanoparticles, plasmonic nanostructure with strong NIR plasmons, NIR absorbing quantum dots and two-dimensional black phosphorous, and on their combination with semiconductors for extending photon absorption into the NIR range for application in solar fuel and photocatalysis [1-8]. Rational design of hybrid nanomaterials, which is the key to maximize the benefits from respective nano-components, is highlighted.
References:

Am. Chem. Soc., 2013, 135, 9616; 2. Adv. Funct. Mater., 2019, under review; 3. Adv. Energy Mater. 2018, 1703658; 4. Adv. Funct. Mater. 2018, 1706235; 5. ACS Catalysis, 2017, 7, 6225; 6. Adv. Funct. Mater, 2015, 25, 2950; 7. Adv. Funct. Mater. 2015, 25, 6650; 8. Nanoscale Horizons, 2019, DOI: 10.1039/C8NH00373D
(Invited) Enhancement of Triplet-Triplet Annihilation-Based Upconversion Emission By Localized Surface Plasmon Resonance
Authors: Sugawa Kosuke , Takeshima Naoto , Jin Shota 
Published: February 2020

The upconversion emission systems using triplet-triplet annihilation (TTA-UC emission) has attracted much attention because these systems can be driven by a noncoherent light with low intensity (e.g. sunlight). Namely, the achievement of efficient TTA-UC emission systems directly leads to the development of high-performance solar energy devices. On the other hand, since the Dexter energy transfer between the sensitizers and the emitters is contained in the process of TTA-UC emission, the emission efficiency is quite low in solid state. We have tried to enhance the emission in solid state TTA-UC systems by interacting with the localized surface plasmon (LSP) resonance of metal nanoparticles.
The anisotropic triangular silver nanoplates (silver nanoprisms: AgPRs) were employed as a plasmonic metal nanoparticle because of the generating wavelength tunability of their LSP resonance and the generation of strong local electromagnetic fields. The hybrids of AgPRs and TTA-UC systems were fabricated by spin-coating the polymer solution containing the sensitizer (palladium(II) tetraphenyltetrabenzoporphyrin: Pd-TPTBP) and the emitter (9,10-bis(phenylethynyl)anthracene: BPEA) onto the AgPRs-immobilized glass plates. When the LSP resonance band of AgPRs spectrally overlapped with both the photoexcitation wavelength of Pd-TPTBP and the fluorescence band of BPEA, the TTA-UC emission was efficiently enhanced. It is reasonable to consider that the former spectral overlap provides the enhancement of TTA-UC emission through the photoexcitation enhancement of Pd-TPTBP (Figure 1). In addition, the threshold excitation intensity (the figure-of-merit in TTA-UC systems) significantly decreased by overlapping the LSP resonance band with the photoexcitation wavelength. Also, it was suggested by the fluorescence lifetime measurements that the enhancement of TTA-UC emission caused by overlapping with the fluorescence band was induced by the efficient nonradiative energy transfer from the singlet excited BPEA to the LSP of AgPRs (Figure 1). On the other hand, when the LSP resonance band overlapped well with the phosphorescence band of Pd-TPTBP, the TTA-UC emission was rather quenched. These results suggest that the nonradiative energy transfer by the LSP resonance from the triplet excited Pd-TPTBP to the LSP became dominant, as compared with the triplet-triplet energy transfer from the Pd-TPTBP to the BPEA. Namely, it was demonstrated that the LSP resonance of AgPRs has both of the positive and negative effects on the solid state TTA-UC emission systems.[1] Furthermore, we investigated the optical interaction between the singlet excited palladium porphyrin and the LSP resonance of AgPRs. Consequently, we will discuss the detailed effects of LSP resonance of the AgPRs on the complicated TTA-UC emission processes.
[1] S. Jin, K. Sugawa et al., ACS Photon., 2018, 5, 5025-5037.

Figure 1
(Invited) Toward Unity Quantum Efficiency for Plasmon Induced Hot Electron Transfer at Metal/Semiconductor Junctions
Authors: Lian Tianquan 
Published: February 2020

It has been well-established that excitation of plasmons in metal nanostructures can lead to the injection of hot electrons into semiconductors or adsorbed molecules, which can be used to enhance photocatalysis. This novel mechanism suggests that plasmonic nanostructures can potentially function as a new class of widely tunable and robust light harvesting and catalytic materials for solar energy conversion. More importantly, it provides a novel approach to access highly energetic and reactive states of metals that is difficult to access with thermal chemistry. However, plasmon-induced hot electron injections from metal to semiconductor or molecules are still inefficient because of unfavorable initial hot electron distribution and the competing ultrafast hot electron relaxation processes within the metallic domain.
In this talk, we discuss two approaches to enhance the efficiency of plasmon induced hot electron transfer. In the first approach, we explore the possibility of enhancing hot electron distribution by decreasing the size of plasmonic Au particles. Using CdS/Au nanorod heterostuctures, we show that the hot electron injection efficiency increases at smaller Au particle size. We attribute this size dependence to increasing contribution of surface assisted plasmon damping, which generates more hot electrons compared to damping by interband transition. In the second approach, we demonstrate that in CdSe/Au hetersostructureswith strong metal/semiconductor coupling, the plasmon decays by direct excitation of an electron from the metal to semiconductor, i.e. plasmon induced interfacial charge transfer transition (PICTT). The new plasmon damping pathway can be very efficient because it bypasses the competition with hot electron relaxation within the metal satisfies both the energy and momentum conservation. We will discuss whether PICTT is a general scheme for efficient hot electron transfer and present preliminary findings of highly efficient plasmon induced hot electron transfer at plasmonic metal/oxide semiconductor interfaces.
High-Entropy Transition Metal Dichalcogenides As Exceptional Electrocatalysts of Hydrogen Evolution Reaction (HER)
Authors: Lan Tian , Hlova Ihor , Pecharsky Vitalij , Pathak Arjun , Balema Viktor , Padalkar Sonal 
Published: February 2020

Hydrogen is a unique energy carrier in that it can be produced via diverse pathways utilizing a variety of available feedstocks, including natural gas, biomass, and water. Electrolysis of water is among the most versatile methods of hydrogen generation that currently play a significant role in hydrogen gas production [1]. Among different water splitting technologies, low temperature electrolysis emerges as superior contender, demonstrating high current density (2 Am-2), low working temperature (82 oC) and operation under high pressures of H2 (~200 bar) [2]. However, one of its main weaknesses is the high cost and scarcity of platinum (Pt), which is an essential element of conventional electrolytic systems. Hence, the development of novel, efficient Pt-free electrocatalysts for hydrogen evolution reaction (HER) belongs to the major objectives of the water splitting materials research.
This talk highlights a new family of high-entropy materials – multi-principal element transition metal dichalcogenides (HE-TMDCs) – that show exceptional electrocatalytic activity approaching the water-splitting activity of platinum in HER. Novel HE-TMDCs, developed with support from Ames Laboratory’s LDRD funding, are single-phase, layered materials, which are built from several different 3d – 5d metals (M = Mo, W, Nb, Ta etc.) and chalcogens (X=S, Se), e.g. (M,M’,M’)(X,X’) [3]. Their electrochemical performance will be presented, and compared with those of conventional binary TMDCs, and Pt. Electrode preparation techniques, the electrochemical measurements and possible reasons for the exceptional performance of the HE-TMDCs electrodes will be discussed.

References

1. https://www.energy.gov/eere/articles/hydrogen-clean-flexible-energy-carrier
2. Schmidt, O. et al. Int. J. Hydr. Energy,
42, 30470 (2017)Hlova, I.Z. et al. Chem. Commun.
54, 12574 (2018)
3. Hlova, I.Z. et al. Chem. Commun.
54, 12574 (2018)
Evaluating Photoelectrochemical Redox Processes for Wastewater Nitrate Removal Coupled with Energy and Nutrient Recovery
Authors: Barrera Luisa , Bala Chandran Rohini 
Published: February 2020

Excessive anthropogenic production of nitrogen fertilizers combined with rapid industrialization has disrupted the natural balance of the nitrogen cycle leading to increased concentrations of reactive-nitrogen/nutrient species including nitrates (NO3
-), nitrites (NO2
-), and ammonium (NH4
+) in groundwater, rivers and lakes1,2. These nutrient imbalances can lead to health risks to human beings by causing methemoglobinemia in infants, also known as “blue baby syndrome,” and may cause cancer in adults, and negatively impact the environment by causing acid rain and algal blooms. Despite the chemical energy that is stored in common dissolved contaminants in water, wastewater treatment poses the challenge of being a highly energy intensive process. In this study we propose a photoelectrochemical approach (see figure below) to oxidize water and reduce nitrates (NO3
-) to various nitrogen-species including N2, and other value-added products such as NH3 and N2O. NH3 can be directly used as a fuel and/or for fertilizer production, and N2O is a powerful oxidant in combustion reactions (used as “nitrox” to supercharge engines of high performance vehicles); in the combustion of methane (CH4), N2O increases the heat released in the reaction by 37% as compared to when O2 is used as an oxidant.
Thermodynamic analyses is first performed to predict the solar energy conversion efficiencies for the various product species. Thermodynamic predictions show that N2O could be a more promising value-added NO3
- reduction product compared to NH3 due to the increased aqueous solubility of the latter, which leads to significant dissolved gas crossover losses. Furthermore, a coupled species transport and reaction kinetics model is developed to predict overall rates of product formation for tandem photoelectrochemical reactor designs. Specifically, the model developed is applied to quantify the influences of competing oxidation and reduction reactions and species mass transport on the energy and nutrient recovery potential of the proposed photoelectrochemical device.
References:

Falkowski, P. et al. The Global Carbon Cycle : A Test of Our Knowledge of Earth as a System. Science (80 ).
290, 291–297 (2000).

Duca, M. & Koper, M. T. M. Powering denitrification: the perspectives of electrocatalytic nitrate reduction. Energy Environ. Sci.
5, 9726 (2012).

Figure 1