bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Battery Durability and Reliability Under Electric Utility Grid Operations
Authors: Dubarry Matthieu , Baure George 
Published: December 2020

Battery Energy Storage Systems (BESSs) show promise to help renewable energy sources integration onto the grid. These systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown.
In this work we analyzed different types of usage for batteries similar to deployed 1MW and 2MW BESS in the Hawaiian archipelago. These batteries are used for a mix of different applications such as voltage smoothing, curtailment, reserve and frequency regulation. With different usages come different battery degradation. A new protocol encompassing all those applications was designed to be able to test the cells and assess their durability in the field. We investigated the impact of frequency regulation duty cycles with different SOC ranges, depth of discharge and temperatures. We also investigated cells with varying duty cycles and temperatures to decipher whether the degradation can be predicted from a laboratory experiment.
Based on the BESS representative usage profiles, we designed cycle-aging and calendar-aging experiments to test the degradation in a controlled fashion. The frequency regulation duty cycle was extracted from a 3 years usage analysis of a previous generation lithium titanate BESS in operation in Hawai'i since 2012. Laboratory testing was used to investigate the degradation in detail to improve remaining useful life predictions. The degradation mechanisms, and their path dependency, were analyzed using incremental capacity analysis and mechanistic modeling. It was found that despite the fact that most of the cells did less than 0.5% capacity after more than 400 days of testing, they actually degraded significantly. Cell temperature had the strongest impact on the loss of lithium inventory whereas duty cycle had a big impact on the loss of positive electrode material. Interestingly, the impact of SOC in the calendar aging experiments, was found to be counterintuitive as batteries lost capacity faster at low SOCs than at high. Based on our results we established a 20 year forecast of the BESS degradation under different usages.
Evaluation of Ageing and Degradation for Lithium-Ion Batteries By Using Electrochemical Harmonic Analysis (EHA)
Authors: Gulsoy Begum , Atalay Selcuk 
Published: December 2020

Lithium-ion cells show a significant degradation in performance with time (1). This occurs as a result of physical and mechanical changes over time that impacts the electrochemical properties and operating parameters throughout the battery lifetime. These can affect the battery performance in terms of a rise in battery impedance and change in the potential difference that are known as a result of nonlinear electrochemical processes of batteries (2, 3). Therefore, the method of observing nonlinear behaviours have been outstanding to understanding and optimising battery performance (1, 3).
In this research, the influences of battery ageing and degradation on harmonic distortion in lithium-ion batteries are investigated to understand nonlinear behaviours of batteries by using Electrochemical Harmonic Analysis (EHA). The study analysed the effects of wide range of temperatures, C-rates and state of charge on battery ageing and degradation. For this purpose, aged and pristine cells are tested in order to analysis harmonic distortion at a specific frequency range between 100mHz and 10kHz.
The comparison of harmonic distortion at the same frequencies for aged and pristine cells illustrates that there is a relationship between ageing phenomena and harmonic distortion. The level of distortion increases proportionally according to the effects of ageing on the battery over time. The distortion was mostly seen in lower frequencies, which were in the range of 100mHz to 10Hz. This distortion proceeded directly from the diffusion process of lithium-ion cells. The findings indicate that lower levels of state of charge and higher temperatures have a decrease in total harmonic distortion (THD).
The principal conclusion of this study is that the difference in the behaviour of aged and pristine cells clearly indicates that EHA technique can be used to identify the degree of ageing and degradation on lithium-ion cells.

Keywords: Electrochemical Impedance Spectroscopy (EIS), Harmonic Analysis, Total Harmonic Distortion (THD), Distortion Integral (DI), Ageing, Degradation, Lithium-ion Battery, Temperature Effect, C-rates, State of Charge (SoC), State of Health (SoH).

N. Harting, R. Schenkendorf, N. Wolff and U. Krewer, Applied Sciences, 8, 821 (2018).

J. Vetter, P. Novák, M. R. Wagner, C. Veit, K.-C. Möller, J. Besenhard, M. Winter, M. Wohlfahrt-Mehrens, C. Vogler and A. Hammouche, Journal of power sources, 147, 269 (2005).

M. Danzer, V. Liebau and F. Maglia, in Advances in Battery Technologies for Electric Vehicles, p. 359, Elsevier (2015).
The Roll-to-Roll Deposition of 2D Nanoflake Films of Semiconducting Tmds for Large Area Solar-to-Chemical Energy Conversion
Authors: Wells Rebekah , Johnson Hannah , Lhermitte Charles Roger , Kinge Sachin , Sivula Kevin 
Published: December 2020

The exceptional semiconducting properties of exfoliated transition metal dichalcogenide (TMDs) nanosheets have long inspired their use in photoelectrochemical applications; in particular, photoelectrodes for solar-to-chemical energy conversion. Indeed, past demonstrations using non-exfoliated, bulk material gave solar-to-hydrogen efficiencies greater than 7%.1 In taking advantage of the exfoliable nature of these materials, nano-TMDs not only provide a new range of tunable optoelectronic properties, but also create a direct path toward ultrathin, flexible devices. However, a major challenge in commercializing TMD-based devices is their large-scale production.2 Our group has recently addressed this issue by developing methods for solution-based fabrication of nanoflake TMD thin films for large area solar energy conversion applications.3 In this presentation we highlight our results employing WSe2 for solar water splitting and report the further advancement of our preparation methods toward a continuous roll-to-roll deposition of TMD-based thin films from nanoflake dispersions using a liquid-liquid interfacial self-assembly technique.3,4 We demonstrate reproducible printing of 100mm wide TMD flake films on plastic substrates at 10 mm s-1 with nanoflake loadings of 35 mg m-2.4 Importantly we show that these large-scale films of semiconducting TMDs are robust and capable of solar-to-chemical energy conversion comparable to that of their batch-scale counterparts.4 In addition, we address the effects of processing conditions on TMD flake quality and optoelectronic device performance. We find that the type of exfoliation and related parameters have a significant impact on the defect density within the flakes, which effects the harvesting of photogenerated charge carriers. We observe this for MoS2 and WSe2-based devices, suggesting that this is a fundamental limitation of liquid exfoliated TMDs. To overcome this limitation we present distinct defect mitigation strategies that can drastically improve the solar energy conversion ability of TMD nanoflake films.5 These techniques lead to state-of -the-art performance of solution-processed WSe2 nanoflake films for photoelectrochemical H2 production with internal quantum efficiency of over 50% and 1 sun photocurrent density over 4 mA cm-2.5

References:

1. J. Am. Chem. Soc., 1, 223-231 (2013).
2. ACS
Energy Lett., 1, 315–322 (2016).
3. Nat. Commun., 6, 7596 (2015).
4. ACS Appl. Nano Mater., 2, 7705-7712 (2019).
5. Nano Lett., 18, 215–222 (2018).

Figure 1
Anodic TiO2 Nanotube Layers: Efficient Photocatalyst
Authors: Sopha Hanna , Motola Martin , Zazpe Raul , Ng Siowwoon , Macak Jan M. 
Published: December 2020

The self-organized TiO2 nanotube layers have attracted considerable scientific and technological interest over the past 13 years motivated by their possible range of applications including photocatalysis, solar cells, hydrogen generation and biomedical uses [1,2]. The synthesis of these 1D TiO2 nanotube layers is carried out by a conventional electrochemical anodization of valve Ti metal sheet.
Among other TiO2 nanomaterials, these nanotube layers stand out due to their directionality, tunability of dimensions, ability to absorb significant amount of incident light and the possibility to utilize nanotube interiors and exteriors for decoration-coating of secondary materials.
One of the most significant applications of TiO2 nanomaterials is photocatalysis, which is very effective to decompose various pollutants (e.g. dyes) and kill bacteria [3,4].
The presentation will focus on the utilization of the nanotube layer for photocatalytic removal of various species in the liquid phase [5, 6] as well as gas phase [7]. We will also show that various secondary materials have a positive influence on photo-electrochemical properties of nanotube layers [8, 9]. Experimental details and some recent photocatalytic results will be presented and discussed.
References:
[1] J. M. Macak et al., Curr.
Opin. Solid State Mater.
Sci.,
2007, 1-2, 3.
[2] K. Lee et al., Chem. Rev., 2014, 114, 9385.
[3] K. Rajeshwar et al., J. Photochem. Photobiol. C: Photochem. Rev.
2008, 9, 171.
[4] Ch. Wei et al., Environ.Sci. Technol.
1994, 28, 934.
[5] J.M. Macak et al., Small, 2007, 3, 300.
[6] H. Sopha et al., Appl. Mater. Today,
2017, 9, 104.
[7] H. Sopha et al., Electrochem. Commun.,
2018, 97, 91.
[8] S. Ng et al., Adv. Mater. Interfaces
2017, 1701146.
[9] F. Dvorak et al., Appl. Mater. Today,
2019, 14, 1.
Heteronanostructured Photocatalysts with Epitaxial Junctions between the Components
Authors: Tada Hiroaki 
Published: December 2020

Heteronanostructured (HNS) photocatalysts are the key material for various important solar-to-chemical transformations. In the semiconductor photoelectrodes, efficient charge separation can be achieved by the Schottky barrier. However, in the particulate HNS photocatalysts, the dimension of semiconductor is usually too small to accommodate the space charge layer. Even if the space charge layer can be formed at the initial stage, the band bending would become weak at the photostationary state due to the accumulation of the electrons in the conduction band. Thus, the major subject in the HNS photocatalysts is the enhancement of charge separation through the efficient interfacial charge transfer between the components for which the construction of the high-quality interface is crucial [1]. On the other hand, Au NP possesses strong and broad absorption in the visible region due to the localized surface plasmon resonance, and loading Au NPs on wide gap semiconductor photocatalysts such as TiO2, SnO2, and ZnO (Au/semiconductor) can induce the visible-light responsiveness and/or work as a catalyst for various reactions [1]. Importantly, the optical property and catalytic activity of Au NPs strongly depend on the size and shape.
This talk focusses on our recent works on the interfacial control in the HNSs at an atomic level, and the effects on the photocatalytic activity. Firstly, a novel nanoscale charge separation mechanism is presented in a HNS consisting of SnO2 nanorods and rutile TiO2 with a heteroepitaxial (HEPI) junction (SnO2-NR#TiO2, # denotes HEPI junction). SnO2-NR#TiO2 shows photocatalytic activity for selective oxidation of ethanol to acetaldehyde much higher than the physical mixture of SnO2 and TiO2 [2]. Secondly, the SnO2-NR#TiO2 charge separator was further modified with Au NPs (Au/SnO2-NR#TiO2) to impart visible-light activity. The Au/SnO2-NR#TiO2 plasmonic photocatalyst exhibits a high level of visible-light activity for the synthesis of H2O2 by two-electron oxygen reduction reaction (ORR) with the assistance of the catalytic activity of Au NP [3]. Thirdly, the HEPI junction-induced shape change of Au NPs is shown to occur on the surface of ZnO in the Au#ZnO system. The extremely high UV-light activity of Au#ZnO for two-electron ORR far exceeding that of Au/TiO2 is discussed in terms of the catalytic activity of Au NPs and the adsorption ability of ZnO for H2O2 [4].
[1] H. Tada, Dalton Trans.
2019, 48, 6308, and the references therein.
[2] K. Awa, R. Akashi, A. Akita, S. Naya, H. Kobayashi, H. Tada, ChemPhysChem
2019, 20, 2155.
[3] K. Awa, S. Naya, M. Fujishima, H. Tada, J. Phys. Chem. C
2020, 124, 7599.
[4] M. Teranishi, S. Naya, H. Tada, J. Am. Chem. Soc.
2010, 132, 7850.
(Invited) SnS2 Thin Film and Powder for Artificial Photosynthesis
Authors: Chen Kuei-Hsien , Shown Indrajit , Chen Li-Chyong , Reta Tadesse Billo , Wu Yu-Kai 
Published: December 2020

Solar photoreduction of CO2 to produce value added hydrocarbons is highly desirable to tackle environmental and energy issues. [1-2] Despite the great improvement in the efficiency and cost of solar cells, the efficiency in artificial photosynthesis is much lower than the >15% of solar cells. Recent progress in 2D chalcogenides with tunable bandgap and layer numbers offers great opportunity for the investigation in this field. In this work, thin film and powder SnS2 have been synthesized for the study. Hydrothermal synthesis of carbon-containing SnS2 exhibits a highly active photocatalytic conversion of CO2 to selective hydrocarbons under visible-light irradiation. Overall, the carbon doping in the SnS2 nanostructure plays a key role and significantly enhance the visible light photocatalytic activity with a photochemical quantum efficiency above 0.7%. [3-4] Meanwhile, Thin film SnS2 has been grown for the mechanism study. By carbon-ion implantation of the thin film, we observed enhanced CO2 reduction under solar illumination. Other FTIR, Raman, NMR, BET, SECM, and synchrotron based facilities including APXPS and XAS have been used to investigate this issue.
1. Shown, H.C. Hsu, Y.C. Chang, C.H. Lin, P.K. Roy, A. Ganguly, C.H. Wang, J.K. Chang, C.I. Wu, L.C. Chen, K.H. Chen, Nano Letters 14, 6097-6103 (2014).
2. Billo, F.Y. Fu, P. Raghunath, I. Shown, W.F. Chen, H.T. Lien, T.H. Shen, J.F. Lee, M. C. Lin, J.S. Hwang, C.H. Lee, L.C. Chen, and K.H. Chen, Small 14, 1702928 (2018).
3. Shown, S. Samireddi, Y.C. Chang, R. Putikam, P.H. Chang, A. Sabbah, F.Y. Fu, W.F. Chen, C.I. Wu, T.Y. Yu, P.W. Chung, M.C. Lin, L.C. Chen, and K.H. Chen, Nature Comm. 9, 169 (2018).
4. T. Billo, I. Shown, A.K. Anbalagan, T.A. Effendi, A. Sabbah, F.Y. Fu, C.M. Chu, W.Y. Woon, R.S. Chen, C.H. Lee, K.H. Chen, L.C. Chen, Nano Energy 72, 104717 (2020).
Photoelectrochemical Nitrogen Fixation for Ammonia Synthesis Using Hybrid Plasmonic Nanostructures
Authors: Nazemi Mohammadreza , El-Sayed Mostafa 
Published: December 2020

Cost-effective production of ammonia via (photo)electrochemical nitrogen reduction reaction (NRR) hinges on N2 electrolysis at high current densities with suitable selectivity and activity [1, 2]. In this talk, we report our findings in electrochemical NRR for ammonia synthesis using porous bimetallic Pd-Ag nanocatalysts in both gas-phase and liquid-phase electrochemical cells at current densities above 1 mA cm-2 under ambient conditions. While the gas-phase cell has lower Ohmic losses and higher energy efficiency, the liquid-phase cell achieved higher selectivity and Faradaic efficiency, attributed to the presence of concentrated N2 molecules dissolved in an aqueous electrolyte and the hydration effects. The liquid cell demonstrated notable performance for electrocatalytic NRR, achieving an NH3 production rate of 45.6 µg cm-2 h-1 at a cathodic potential of -0.6 V (vs. RHE) and current density of 1.1 mA cm-2, corresponding to a Faradaic efficiency of ~19.6% and an energy efficiency of ~9.9%. Similarly, the gas-phase cell achieved an NH3 yield rate of 19.4 µg cm-2 h-1 at -0.07 V (vs. RHE) and 1.15 mA cm-2 with a Faradaic efficiency of 7.9% and an energy efficiency of 27.1%. In addition, the photoelectrocatalytic activities of these hybrid plasmonic nanostructures under illumination and dark conditions will be explored and photocurrent and photovoltage responses will be reported. Operando surface-enhanced Raman spectroscopy (SERS) is used to identify the intermediate species relevant to NRR at the solid-liquid (electrode-electrolyte) interface. This work highlights the importance of design and optimization of cell configuration in addition to the modification of the catalyst to achieve high-performance N2 electrolysis for ammonia synthesis. It also demonstrates the use of operando SERS as a powerful technique for unraveling reaction mechanisms for (photo)electrocatalytic phenomenon.
[1] M. Nazemi, L. Soule, M. Liu, M. A. El-Sayed, “Ambient Ammonia Electrosynthesis from Nitrogen and Water by Incorporating Palladium in Bimetallic Gold-Silver Nanocages” Journal of The Electrochemical Society, 167(5), p. 054511, 2020.
[2] M. Nazemi, M. A. El-Sayed, “Plasmon-Enhanced Photo(electro)chemical Nitrogen Fixation under Ambient Conditions Using Visible Light Responsive Hybrid Hollow Au−Ag2O Nanocages” Nano Energy, vol. 63, 103886, 2019.
(Invited) Thermoplasmonic Generation of Carbon Nanohydrids for Enhanced Electrocatalysis
Authors: Naldoni Alberto 
Published: December 2020

Local heating from plasmonic nanostructures has shown great potential in photothermal therapy, optical trapping, heterogeneous catalysis, and synthesis of nanostructures. Titanium nitride (TiN) is one the most promising plasmonic materials for thermal applications (thermoplasmonics) due to its high thermostability (i.e.
refractory), CMOS compatibility, and resistance to chemically harsh environments. On the other hand, hydrogen peroxide (H2O2) has a large annual production approaching 4 ×106 tons worldwide and the selective reduction of O2 via electrochemical oxygen reduction reaction (ORR) using renewable electricity is a promising way for H2O2 production. Carbon-based materials have shown great potential for the two-electron ORR to hydrogen peroxide. In this contribution, I will show a general approach to use the highly intense local temperature generated from plasmonic TiN nanocrystals for generating TiN/carbon nanohybrids that show enhanced efficiency and selectivity toward the ORR. The general applicability of plasmon-driven synthesis of nanocarbons to electrocatalysis will be discussed.
(Invited) Ultrafast X-Ray Studies of Electron Dynamics Underlying Molecular and Nanoplasmonic Light Harvesting Architectures
Authors: Gessner Oliver 
Published: December 2020

Chemically engineered light harvesting architectures based on molecular and nanoplasmonic chromophores in contact with semiconducting electron acceptors provide exciting opportunities for novel photocatalytic and photovoltaic applications. Optimizing their performance, however, often hinges on a deeper understanding of the underlying fundamental electronic and chemical dynamics. Processes evolving on spatial and temporal scales spanning many orders of magnitude have to be connected in order to enable molecular, interfacial, and macroscopic charge and energy transport. We will discuss the application of ultrafast X-ray spectroscopy techniques to gain deep insight into photoinduced electronic dynamics in complex, heterogeneous light-harvesting systems based on organic heterojunctions as well as molecule-semiconductor and metal nanoparticle-semiconductor interfaces.
Femtosecond and picosecond time-resolved X-ray photoelectron spectroscopy (TRXPS) is used to study photoinduced charge injection in N3 dye-sensitized films of ZnO nanoparticles. The elemental site-specificity and surface sensitivity of TRXPS provides a comprehensive real-time picture of the interfacial charge dynamics including the locations of intermittently trapped electrons, the emergence and decay of interfacial dipoles, as well as charge-injection induced band-bending dynamics in the semiconductor substrate. Potential consequences of the findings for the design of dye-sensitized nanoporous electrodes are discussed.
TRXPS studies of photoinduced dynamics in copper-phthalocyanine(CuPc)-C60 heterojunctions provide a deeper understanding of the predominant energy transport and charge generation mechanisms. Ultrafast X-ray probing captures the actual moment of charge generation from interfacial charge-transfer (ICT) states and provides a quantitative measure of the exciton dissociation efficiency compared to photon energy loss by exciton recombination. The findings complement observations with ultrafast optical techniques, adding important aspects regarding the dynamic pathways and branching ratios that govern charge generation efficiencies in this canonical model system for organic light harvesting concepts.
In a third showcase example, photoinduced charge transfer dynamics in a nanoporous film of TiO2 sensitized with gold nanoparticles (AuNPs) is monitored by TRXPS. Direct access to the absolute photon-to-charge conversion efficiency and subsequent electron-hole recombination dynamics is demonstrated with single-electron sensitivity. The results provide important boundary conditions for the design of AuNP-TiO2 based light harvesting systems. Opportunities for extending the measurements toward studies of photoinduced interfacial chemical transformations will be discussed.
Photoelectrochemical CO2 Reduction Using CuInS2 Photocathode Modified with CdS and Noble Metal Catalysts
Authors: Fujishiro Yukitaka , Takashima Toshihiro , Irie Hiroshi 
Published: December 2020

Photoelectrochemical CO2 reduction using sunlight is a promising approach to producing a clean energy carrier that could replace fossil fuels, providing a sustainable future energy supply. Copper chalcopyrite compounds, Cu(In,Ga)(S,Se)2, have recently received considerable attention as promising candidates for photocathodes owing to their high absorption coefficients and high carrier mobilities, and efficient photoelectrochemical H2 production using a series of Cu(In,Ga)(S,Se)2-based photocathodes has been demonstrated. Moreover, the photoelectrochemical performance of these photocathodes has been reported to improve when combined with n-type semiconductor buffer layers due to the formation of a p–n junction, which facilitates charge separation at the interface. Meanwhile, noble metal catalysts have been widely used to catalyze redox reactions efficiently because they can lower the overpotential for desirable reactions. Especially, some Au and Ag catalysts have been reported to proceed highly efficient and selective electrochemical CO2 reduction. Based on these backgrounds, in this study, we investigated photoelectrochemical CO2 reduction using CuInS2 electrode modified with CdS buffer layer and noble metal catalysts.
CuInS2 thin film electrodes were synthesized on Mo foil using electrodeposition and subsequent sulfurization. The electrode surface was modified with CdS by chemical bath deposition method, followed by photoelectrochemical deposition of Pt, Au, and Ag. As shown in Figure, the prepared photoelectrodes showed distinct photocurrent generation under visible light irradiation. Modification with noble metal catalysts was effective to enhance the photoresponse and the photocurrent density increased in the order of Pt > Au > Ag. As a result of photoelectrolysis at -0.1 V vs RHE in CO2-saturated NaHCO3 solution, generation of CO was confirmed from all the electrodes although the Faradaic efficiency was different depending on the noble metal catalysts. Details will be discussed at the conference.
References
[1] W. Septina, Gunawan, S. Ikeda, T. Harada, M. Higashi, R. Abe, M. Matsumura, J. Phys. Chem. C 119 (2015) 8576–8583.
[2] Gunawan, Wilman Septina, Shigeru Ikeda, Takashi Harada, Tsutomu Minegishi, Kazunari Domen, Michio Matsumura, Chem. Commun., 50 (2014), 8941
[3]Weichum Ye, Junfeng Yan, Qian Ye, Feng Zhou J. Phys. Chem. C., 114 (2010), 15617

Figure 1