bluuebunny/crossref_metadata_2025_split huggingface dataset:
Imaging Li and Resolving the Degradation Mechanism of All-Solid-State Li-Ion Batteries
Authors: Gong Chen , Jadidi Zinab , El Gabaly Farid , Fuller Elliot James , Talin Albert Alec , Leite Marina S 
Published: February 2020

All-solid-state Li-ion batteries (SSLIBs) with enhanced safety are a promising candidate for large-scale energy storage applications, such as hybrid vehicles. However, further improving the electrochemical performance requires controlling and suppressing the degradation mechanism for SSLIBs upon cycling. To reveal the nature of the irreversible reaction that takes place in SSLIBs, we combine scanning/transmission electron microscopy (S/TEM), X-ray photoelectron spectroscopy (XPS), conductive atomic force microscopy (c-AFM), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). We directly image Li ions within each battery component during charging/discharging for SSLIBs with Al and Si anodes. We observe the formation of an Al-Li-O complex capping the AlLi alloy on the strain-free surface of the Al anode using S/TEM and XPS [1, 2]. We found that this layer is insulting through c-AFM and therefore retards electrons to flow in and out of the anode, ultimately leading to the poor capacity retention. For comparison, we fabricate SSLIBs with Si anodes, a high-capacity material. We identify the electrical property of the Si anode remaining intact after cycling by c-AFM. This battery shows a Coulombic efficiency of ~98% after 100 cycles, see Fig. 1.
To further investigate the irreversible lithiation process of Si anode SSLIBs, we directly map Li ions by ToF-SIMS. We determine the Li distribution within all active layers (anode, electrolyte, and cathode) at three state-of-charge: pristine, charged, and cycled. We demonstrate a remarkable spatial variation of Li concentration within the anode upon the first charging, later the ions are trapped and cannot be fully extracted from the anode during subsequent cycles. The accumulation of foreign ions within the Si anode is detrimental to the structure integrity, resulting in the capacity loss after cycling the device [3]. Moreover, we identify “hot spots” of Li ions within the LiPON electrolyte, which could be ascribed to the amorphous nature of LiPON. Overall, we provide critical information about how the capacity fades and where the irreversible lithiation happens. Our results will undoubtedly contribute to the design of energy storage devices with enhanced performance.
[1] M. S. Leite et al., J. Mater. Chem. A
2014,
2, 20552. i-­Cover

[2] C. Gong et al., ACS Appl. Mater. Interfaces
2015,
7, 26007. ­Cover

[3] C. Gong et al., In preparation
2017

Figure 1
Superior Shelf Life and Moisture Tolerance of ALD-Coated Cathode Materials As Important Aspect of ALD-Based Improvements of Li-Ion Cell Cycle Life
Authors: Venkat Maithri , Dahlberg Kevin , King David M , Meyer Harry M , Ruther Rose Emily , Wood David L , Stevenson Lisa , Townsend Dennis 
Published: February 2020

Lithium-ion battery-based energy storage is widely regarded as the best technology to realize affordable electrification of automobiles (hybrids and EVs), buses, and ships. However, strategies to realize higher energy density and lower cost come at the expense of cell lifetime and safety. Extensive effort has been devoted to studying the effects of ALD coatings on cathode materials, with varying reports of the impact on full cell cycle life. The changes in surface chemistry of ALD-coated cathode particles and their specific effects on electrochemical performance have not been studied in detail. Unmodified particle surfaces contain active oxygen, LiOH, and Li2CO3 species. The chemistry of these species during delithiation and interaction with the electrolyte can introduce components of impedance that can limit the capacity and rate capability of the material. Moisture adsorption can occur over time which can interact with and generate more of these species, causing a further deterioration of capacity. We have shown that important functions of ALD are to “clean” the particle surfaces, decreasing the content of LiOH and moisture, and forming a barrier to water adsorption and further generation of these species. Thus an important mechanism of ALD enhancement of cathode materials in full cells is demonstrated. This understanding should be applied to past and future studies, and represents a powerful new strategy to mitigate the effects of moisture.
(Invited) HQ Characterisations Techniques for Li-Ion and Solid State Batteries
Authors: Zaghib Karim , Hovington Pierre , Wen Zhu , Trudeau Michel , Paolella Andrea , Vijh Ashok , Guerfi Abdelbast , Julien Christian M , Mauger Alain , Armand Michel 
Published: February 2020

In these presentation, we will present the data and movies of several an operando techniques to study lithium ion and solid state batteries such in situ SEM, In situ TEM, in situ Raman spectroscopy , in situ X-ray diffraction and in situ UV visible. These studies help to understand several mechanism such volume expansion of anodes such lithium metal (20 %), Graphite (10 %), LTO (0 %) and another example the measurements of the thickness of anode, cathode and electrolyte during charge discharge. The mechanism of lithium dendrite was also study and details will be shown during this presentation.
Bleand Lithium/solid polymer electrolyte (SPE)/sulfur cells were studied in operando by two techniques: Scanning Electron Microscope (SEM) and ultraviolet-visible absorption spectroscopy (UV-vis). During the operation of the cell, extensive polysulfide dissolution in the solid polymer electrolyte (cross-linked polyethylene oxide) leads to the formation of a catholyte.
A clear micrograph of the thick passivation layer on the sulfur-rich anode and the decreased SPE thickness by cycling confirmed the failure mechanism; the capacity decays by reducing the amount of active material, and by contributing to a charge inhibiting mechanism called polysulfide shuttle. The formation of elemental sulfur is clearly visible in real time during the charge process beyond 2.3 V. The non-destructive in operando UV-vis study also shows the presence of characteristic absorption peaks evolving with cycling, demonstrating the accumulation of various polysulfide species, and the predominant formation of S4
2- and of S6
2- during discharge and charge, respectively. This finding implies that the charge and discharge reactions are not completely reversible and proceed along different pathways.
Electrochemical Cells for Operando Time-of-Flight Neutron Diffraction Study of Li/Na-Ion Electrode Materials
Authors: Bobrikov Ivan A. , Ivanshina Olga Yu , Sumnikov Sergey V , Samoylova Natalia Yu , Balagurov Anatoly M. 
Published: February 2020

In-situ and operando neutron powder diffraction are well established methods for studying structural changes in Li-ion electrode materials in real time during battery operation. Quality of diffraction data obtained in operando experiments depends on characteristics of diffractometer (brightness, space resolution) and design and assembly of electrochemical cell. Operandoneutron diffraction experiments can be successfully performed with real batteries; however using special designed electrochemical cell allows us to exclude some undesirable reflexes of battery components from diffraction pattern, use Li-metal as counter electrode, decrease background from incoherent scattering elements, be almost independent from commercial machines for battery preparation and considerably reduce a mass of investigated materials.
In this report we present special designed electrochemical cells developed for operando study of Li-ion electrode materials at time-of-flight neutron diffractometers at the IBR-2 neutron source (Dubna, Frank Laboratory of Neutron Physics). The cells are easily assembled in a glove box and demonstrate the excellent parameters of cyclabilities (with graphite electrodes, more than 700 cycles) and absence of leakage current. In dependence of scattering properties of studied materials the measured diffraction patterns can be analyzed by Rietveld method or Peak’s profile data analysis. Several successful operando experiments on Li-ion electrode materials using these cells have been performed. In particular, investigation of LiNi0.8Co0.15Al0.05O2(NCA) cathode material in the electrochemical cell allowed us to reveal the microstructural reasons of phase separation that occurs in cycled NCA during the first charge.
[1] A. M. Balagurov, I. A. Bobrikov, N. Yu. Samoylova, O. A. Drozhzhin, E. V. Antipov, RUSS CHEM REV. 2014, 83(12), 1120–1134
Thermal Conductivity Study on a Working Li-Ion Battery Cell
Authors: Cao Lei , Hartig Julia , Santhanagopalan Shriram 
Published: February 2020

Lithium-ion batteries have been popular powering mobile electronics and electric vehicles owing to its high energy density and good electrochemical performance. However, thermal transport performance, especially in cross-plane direction, is not on a par with electrochemical ones. Poor thermal transport may result in overheating and even thermal runaway while there’s still a lack of methods studying battery electrode thermal conductivity under working condition1. Previous efforts provide measurement on either dry battery electrodes or reassembled electrodes with electrolyte but not being able to charge and discharge2, 3. Current study demonstrates a new method measuring thermal conductivity of a working battery cell through flash diffusivity technique. By minimizing contact resistance between electrode sample and holder, the work can contribute to comprehensive study of a working battery cell for better thermal performance.
1. V. Vishwakarma, C. Waghela, Z. Wei, R. Prasher, S. C. Nagpure, J. Li, F. Liu, C. Daniel, and A. Jain, Journal of Power Sources,
300 123-131 (2015).
2. H. Maleki, S. A. Hallaj, J. R. Selman, R. B. Dinwiddie, and H. Wang, Journal of The Electrochemical Society,
146 (3), 947-954 (1999).
3. S. C. Nagpure, R. Dinwiddie, S. S. Babu, G. Rizzoni, B. Bhushan, and T. Frech, Journal of Power Sources,
195 (3), 872-876 (2010).
High Speed Blind Via Filling By Copper Electrodeposition
Authors: Lo Chun-Hsiang , Dow Wei-Ping 
Published: February 2020

Blind vias filling by direct-current copper electroplating is widely used in printed circuit boards (PCBs) to increase input/output (I/O) density due to high density interconnection. The blind vias of a PCB can be filled perfectly by copper electroplating using organic additives such as suppressor, leveler and accelerator in a copper plating bath. However, the current density cannot be raised too high because a void is easily formed at the blind via after filling plating at a high current density. Therefore, this work is to adjust the ratio of organic additives to fill the blind vias of a PCB by copper electroplating at 25℃~30℃ and at a high current density (i.e., 5 A/dm2). The filled blind vias were examined by cross-sectional analysis using an optical microscope (OM) and a scanning electron microscope (SEM). In addition, synergistic effect of organic additives on copper deposition was analyzed by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) to explain how did these additives work for superfilling of the blind via at the high current density.
A Self-Forming Membrane for Advanced Electrochemistry-Based CO2 Capture
Authors: Zhang Peng , Tong Jingjing , Huang Kevin 
Published: February 2020

The presentation describes a new type of low-cost and easy-to-fabricate mixed e- and CO3
2- conducting membrane for advanced high-flux and selective electrochemical CO2 separation from flue gas. The membrane is consisted of a CO3
2--conducting molten carbonate phase and an e--conducting lithiated Ni-oxide interphase formed in situ during operation. The testing results explicitly show that the membrane exhibits a CO2 flux density >1.0 mL min-1 cm-2 at 850 oC with a selectivity of 100-500 and excellent stability for 450 hours. Compelling experimental evidence is also provided to support that the self-formed interphase Li0.4Ni1.6O2 is highly electronic conducting and responsible for providing electrons to the co-reduction of CO2 and O2 into CO3
2-. Given the performance level demonstrated, this low-cost and easy-to-fabricate membrane is superior to the conventional “size-sieving” inorganic and “dissolution-diffusion” organic counterparts, promising it to be a very competitive technology for future advanced CO2 capture from flue gas.
Composite Photoelectrocatalysts for Tempo-mediated Alcohol Oxidations
Authors: Chadderdon David J , Wu Ivy , Panthani Matthew G , Li Wenzhen 
Published: February 2020

The transformation of primary alcohols to higher valuable carbonyls or acids has attached enormous attention from both academic and industrial viewpoints, but typically requires stoichiometric oxidants, which are costly and generate potentially toxic waste. Previously, we have studied selective electrocatalytic oxidation of biomass-derived alcohols and 5-hydroxymethylfurfural (HMF) on noble metal catalysts.[1-3] Electroactive homogeneous catalysts such as (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) represent an alternative to expensive metal catalysts.[4] Conversion of biorenewable feedstock in a photoelectrochemical cell (PEC) [5] is potentially one of the most environmentally-friendly chemical production routes available, which takes advantage of renewable carbon sources from the earth, renewable photons from the sun, and renewable electrons from wind, geothermal, or photovoltaic sources. However, there is a need to develop new composite materials which can simultaneously facilitate light absorption, charge separation, charge transport, and electrochemical reactions. We have investigated the use of composite photoanodes for efficient TEMPO-mediated oxidations. Bismuth vanadate (BiVO4) semiconductor films modified with an earth-abundant cobalt phosphate (Co-Pi) layer facilitated TEMPO oxidation at overpotentials almost 500 mV lower than unmodified BiVO4, while simultaneously suppressing the undesired oxygen evolution reaction. The photoanode materials were characterized using XRD, XPS, SEM, EDS, UV/vis and photoelectrochemical measurements. The composite photoanodes achieved complete oxidation of HMF to 2,5-furandicarboxylic acid (FDCA) with 88% yield, whereas an unmodified BiVO4 only reached partial oxidation intermediates (FDCA yield <1%) under the same conditions. Transient photocurrents revealed the role of Co-Pi for promoted TEMPO oxidation is two-fold: (1) to efficiently remove photogenerated charges from the semiconductor and (2) promote charge transfer across the catalyst-electrolyte interface for TEMPO oxidations.

References:

(1) Zhang, Z.Y. et al., Appl. Catal. B, (2012), 119, 40-48.
(2) Chadderdon, D. J. et al., Green Chem. (2014), 16 3778–3786.
(3) Chadderdon, D. J. et al., ACS Catal. (2015), 5 6926−6936.
(4) Rafiee, M.; Miles, K. C.; Stahl, S. S., JACS (2015), 137 14751−14757.
(5) Cha, H. G.; Choi, K. S., Nature Chem. (2015), 7 328–333.
Electrochemical Flow Cell for the Upgrading of Biomass Derived Streams
Authors: Diaz Luis A. , Lister Tedd E. 
Published: February 2020

Abstract

The upgrading of biomass derived streams (BDS) provides a unique opportunity for the synthesis of fuel and chemicals completely derived from renewable sources. In order to achieve a complete greenhouse gas neutral fuel, the upgrading process needs to comply with high energy efficiencies and be able to totally rely in renewable resources as inputs and feedstock. However, one of the main challenges in the utilization of BDS comes from the nature and composition of the original sources, specifically, from the large oxygen content present in the carbohydrate polymers that compose the lignocellulose biomass in comparison with fossil sources [1]. The high concentration of oxygen, carbonyls, and phenolic groups present, directly translate in instability and poor physicochemical properties for their incorporation in the current refinery infrastructure. This drives the need to develop upgrading processes which are tailored to future energy schemes.
Electrochemical reduction is the only technology that can be directly powered by renewable energy sources, and do not require external addition of hydrogen, as this can be generated in-situ. In this work cathode formulations and membrane electrode assembly architectures have being engineered to allow a selective and efficient upgrading of BDS in a flow cell electrolyzer. Experimental results with surrogates and biomass derived streams will be presented.

References

[1] D. Mohan, C.U. Pittman, P.H. Steele, Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review, Energy & Fuels, 20 (2006) 848-889.
Room Temperature Photoluminescence Characterization of Silicon Wafers for In-Line Monitoring Applications
Authors: Yoo Woo Sik , Ishigaki Toshikazu , Kang Kitaek 
Published: February 2020

Performance variations and yield loss in advanced Si devices are closely related to the quality of the semiconductor surface and interfaces. These are very significant factors for successful development of advanced devices. In addition, proper implementation of manufacturing processes is critical as devices scale to smaller size and complexity of device structures increase. The importance of proper understanding and control of surface cleaning and passivation of silicon and dielectric/Si interface quality, is more important than ever. Characterization techniques for determining the effectiveness of Si cleaning, surface passivation and the dielectric/Si interface include Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), high resolution cross-sectional transmission electron microscopy (HRXTEM), non-contact I-V, C-V and carrier lifetime measurements. Various chemical analysis techniques are also used for determining contamination sources in manufacturing. While the conventional characterization techniques have been providing useful information on the properties of the dielectric/Si interface, they cannot sufficiently provide substantive clues for many puzzling problems of Si surface cleanliness, Si surface passivation and the dielectric/Si interface.
In this paper, overall quality of the Si surface and dielectric/Si interface (including cleanness, passivation and surface recombination characteristics) were characterized using room temperature photoluminescence (PL) spectroscopy. The spatial resolution of PL spectroscopy is tens of microns. To understand the depth distribution of electrically active defects/traps, at or near the Si surface and the dielectric/Si interface, different excitation wavelengths (with different probing depths) were used as the light source. Significant variations in electrically active defects, traps, and contaminants, at or near the surface, and the dielectric/Si interface were found from multiwavelength PL spectroscopic studies of Si with native oxide. Non-contact, multiwavelength PL spectroscopy was able to reveal electrically active defects and characteristics induced by the cleaning process used, which cannot be properly investigated using conventional chemical analysis and dielectric/Si interface characterization techniques.
Stability of SiGe(100) Surfaces after Ammonium Sulfide Passivation
Authors: Heslop Stacy Lynn , Peckler Lauren , Muscat Anthony J. 
Published: February 2020

Germanium and silicon germanium are attractive channel materials for transistors. Germanium has a smaller band gap and higher hole mobility than silicon, and varying the Ge concentration is one means of tuning the properties of SiGe alloys. Although these materials have many potential benefits, they are challenging to work with. The native oxide, GeO2, is water soluble and therefore cannot protect the surface during aqueous processes. One option is to deposit a layer that chemically passivates the surface after cleaning to protect it from reoxidation. Sulfur could passivate the surface due to its size and valency. Since the dominant cleaning technology is wet, aqueous ammonium sulfide could be a viable option. While ammonium sulfide processes deposit sub-monolayer coverages of sulfur on germanium, the surface reactions on SiGe surfaces are vastly different.
Our study focuses on the treatment of Si-rich SiGe surfaces (Si1-xGex x=0.25) with aqueous (NH4)2S. We varied the concentration of (NH4)2S in solution with and without added acid and characterized the surfaces using X-ray Photoelectron Spectroscopy (XPS). Immersions in (NH4)2S alone oxidized the surface and did not deposit a sulfide layer. Instead the surface oxidized as a function of the (NH4)2S concentration. In order to remove the oxide and slow down or stop the oxidation, small volumes of HF and HCl were added to the mixture. Addition of halogen acids dropped the pH of the solution from 10 to 8 and sulfides were detected with XPS in the S 2p region. Sulfur coverage increased with increasing concentrations of HF and HCl, however oxides increased as well. The simultaneous deposition of sulfur and oxygen suggests that oxidized sulfur, such as sulfates and thiosulfates, deposited on the surface.
In addition to chemical characterization of the surface, metal-insulator-semiconductor capacitors (MISCAPs) were fabricated after three different surface treatments: 1) clean and dry (control), 2) cleaning and immersion in (NH4)2S and 3) cleaning and immersion in (NH4)2S with added acid. Capacitance-voltage measurements were obtained for all three surface treatments. The density of interface defects (Dit) was calculated for each process from conductance and capacitance data. Processes that yielded the highest sulfur coverage (ammonium sulfide with added acid) showed a reduction in Dit (1.4 x 1012 cm-2 eV-1) compared to samples that were cleaned and dried only (6.4 x 1012 cm-2 eV-1) and samples treated with aqueous ammonium sulfide (4.4 x 1012 cm-2 eV-1).