bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Oxidation of Lignin Using a Novel Lead-Free Electrocatalyst
Authors: Ghahremani Raziyeh , Staser John A. 
Published: February 2020

To diminish reliance on the oil industry as a supplier of aromatic compounds, developing an economically viable lignin conversion process is crucial. The cost of depolymerization process should be low to be competitive on the fuel market [1]. Electrochemical oxidation of lignin offers several advantages over catalytic or enzymatic processes such as having control over the reaction by controlling the potential or current, environmental friendliness of electron reagents for electrochemical reaction, feasibility of the process at relatively low temperature and pressure, and simultaneous production of H2 [2]. Lead dioxide is one of the common active and inexpensive catalysts for electrochemical oxidation of lignin, however, environmental regulations have aimed to eliminate using lead due to its toxicity. Therefore, the aim of this research study was to develop an efficient, stable and non-toxic electrocatalyst with a high catalytic activity toward lignin oxidation, and minimal deactivation over time. A flow electrochemical reactor was used to oxidize lignin at the anode side with simultaneous hydrogen generation at the cathode side. A comprehensive protocol was also used to quantify oxidation product concentrations via internal standard method using GC-MS.

References

[1] G. Chatel, R.D. Rogers, Review: Oxidation of Lignin Using Ionic Liquids—An Innovative Strategy To Produce Renewable Chemicals, ACS Sustain. Chem. Eng. 2 (2014) 322–339.
[2] R. Ghahremani, J.A. Staser, Electrochemical oxidation of lignin for the production of value-added chemicals on Ni-Co bimetallic electrocatalysts, Holzforschung. 72 (2018) 951–960.
Electrochemical Properties of Petroleum Coke As Active Material of Negative Electrode in Lithium Batteries
Authors: Kuzmina Elena , Chudova Nadezhda , Prosochkina Tatyana , Karaseva Elena , Kolosnitsyn Vladimir 
Published: February 2020

The possibility of usage of petroleum coke as active materials of negative electrodes in lithium batteries was studied in presented work.
Studies show that crude petroleum coke has high specific resistance (1.4·107 Ohm·cm), that is in 7 times greater than the resistance of graphite (0.5-1.0 Ohm·cm), used as the active material of negative electrodes in lithium-ion batteries. Thermal treatment of crude petroleum coke at 800 °C in the atmosphere of air or nitrogen during 5 hours decreases the specific resistance to 1.3 and 1.5 Ohm·cm, correspondingly, and increases their specific surface area from <0.1 m2/g to 5.3 m2/g (nitrogen) and 0.7 m2/g (air). Specific surface area was estimated by sorption of dyes (methyl orange).
Crude petroleum coke is not electrochemical active and can not be DC cycled (Figure). Heat treatment of petroleum coke, both in the atmosphere of air and in the atmosphere of nitrogen, leads to the appearance of electrochemical activity and the ability to reversibly intercalate lithium ions. At DC cycling of electrodes based on heat-treated petroleum coke in the range of voltage of 0 - 1.0 V vs Li/Li+ the reversible capacity is 300-350 mA·h/g.
The shapes of charge and discharge curves (Figure) of semi-cells with electrodes based on petroleum coke are similar to the charge-discharge curves of semi-cells with electrodes based on structurally disordered carbons.

This work was performed as part of the Government Order to Ufa Institute of Chemistry of the Russian Academy of Sciences by the Ministry of Science and Higher Education of the Russian Federation (Theme No. AAAA-A17-117011910031-7).

Figure 1
Generation and Evolution of Materials in the Anode Solid Electrolyte Interphase (SEI) of Lithium Ion Batteries
Authors: Lucht Brett 
Published: February 2020

A solid electrolyte interphase is generated on the anode of lithium ion batteries during the first few charging cycles. The presence and stability of the solid electrolyte interphase (SEI) is critical to the performance of the battery. Despite thorough investigation of the SEI for over 20 years, the mechanism of formation and function are still relatively poorly understood. We have investigated the structure of the initial SEI on graphite and silicon electrodes along with changes which occur to the SEI upon additional cycling via a combination of ex-situ surface analysis techniques. The investigation of SEI provides significant insight into the structure and properties of the anode SEI.
The one electron reducing agent, lithium napthalenide has been used to independently prepare the reduction products which constitute the SEI. The initial reduction product of ethylene carbonate is lithium ethylene dicarbonate (LEDC). However, the thermal decomposition of LEDC and related lithium alkyl carbonates in the presence of LiPF6 generates a intricate mixture of compounds which greatly complicates the structure of the SEI. The reduction products and their subsequent thermal decomposition products have been thoroughly investigated via a combination of NMR, XPS, IR-ATR, TGA, and GC-MS. Mechanisms for the generation of the complicated mixture of products will be discussed.
Thermal behavior of the SEI on a silicon electrode for Lithium ion batteries has been investigated by TGA. In order to provide a better understanding of the thermal decomposition of the SEI on silicon, the thermal decomposition behavior of independently synthesized lithium ethylene dicarbonate (LEDC) was investigated as a model SEI. The model SEI (LEDC) has three stages of thermal decomposition. Over the temperature range of 50~300oC, LEDC decomposes to evolve CO2 and C2H4 gasses leaving lithium propanoate (CH3CH2CO2Li) and Li2CO3 as solid residues. The lithium propanoate decomposes over the temperature range of 300~600oC to evolve pentanone leaving Li2CO3 as a residual solid. Finally, the Li2CO3 decomposes over 600oC to evolve CO2 leaving Li2O as a residual solid. A very similar thermal decomposition process is observed for the SEI generated on cycled silicon electrodes. However, two additional thermal decomposition reactions were observed characteristic of LixPOyFz at 300oC and the polyimide binder at 550oC. TGA measurements of Si electrodes after various numbers of cycles suggest that the LEDC on Si electrodes thermally decomposes during cycling to form lithium propanoate and Li2CO3, resulting in increased complexity of the SEI.
Electrolyte Development and Its Application for Fast Charging of Li-Ion Batteries
Authors: Du Zhijia , Wu Xianyang , Wood David L. , Zhao Kejie , Belharouak Ilias 
Published: February 2020

Energy density, cost and safety are, more than ever, the most significant barriers to overcome in order to increase the wide acceptance of Li-ion batteries (LIBs) in electric vehicles (EVs).1 The U.S. Department of Energy (DOE) has set ultimate goals for battery electric vehicles (BEVs), which include reducing the production cost of the battery pack to $150/kWh, increasing the electrical range of the battery to 300 miles, and decreasing the charging time to 15 minutes or less.2 Increasing electrode thickness, and hence increasing active material loading, is an effective way to achieve these energy density and cost targets.3 The caveat, however, is that thicker electrodes fail during fast charging.
One of the solutions for enabling extreme fast charging while retaining most of the battery energy can be achieved through the significant enhancement of the Li-ion mass-transport in electrolytes such that enough Li ions are available for intercalation in graphite. The mass transport of Li-ions can be evaluated by two macroscopic characteristic values: 1) the Li ions ionic conductivity that is related to the total flux of charge carriers, 2) the Li ion transference number that is related to the fraction of the total current that is carried by Li ions. An electrolyte with both higher Li ions conductivity and transference numbers is ideal for higher Li ions transport, and hence would be a step toward realizing cells with higher charging rates.
The fast charging performance of high-energy density (NMC811/graphite) Li-ion cells iss studied when different lithium salts were used in the electrolyte. The new electrolyte shows both higher ionic conductivity and Li-ion transference number compared to LiPF6 electrolyte. During a 12-minute fast charging step, cells with LiPF6 electrolyte reached the cut-off voltage in 4.2 minutes, which is much earlier compared to 7.4 minutes for the new electrolyte. The new electrolyte showed 13% capacity improvement in the first cycle of the 12-minute charge. The capacity retention was also significantly higher at 87.7% after 500 cycles with less lithium plating observed.
(1) Needell, Z. A.; et al. Potential for Widespread Electrification of Personal Vehicle Travel in the United States. Nat. Energy
2016, 1 (9).
(2) Howell, D.; et al. Enabling Fast Charging: Enabling Fast Charging: A Technology Gap Assessment. 2017, No. October.
(3) Du, Z.; et al. Understanding Limiting Factors in Thick Electrode Performance as Applied to High Energy Density Li-Ion Batteries. J. Appl. Electrochem.
2017, 47 (3), 405–415.

Figure 1
Coconut Sprout-Derived Graphitized Carbon Based Sodium Ion Capacitors
Authors: Surendran Vishnu , Suviresh Arya Raveendran , Vineesh Thazhe Veettil , Babu Binson , Shaijumon Manikoth M 
Published: February 2020

Electrochemical Energy storage systems such as rechargeable batteries and supercapacitors play vital role in many applications like portable electronics, electric vehicles, smart electric grids etc. There is always a trade off between the performances of the two devices, with batteries offering high energy density, and supercapacitors exhibiting high power density. Hybrid ion capacitor (HIC), a new concept of energy storage device, wherein the best properties of a battery and a supercapacitor are combined, is attracting lot of interest in recent times.1 Typically, a battery-type electrode is chosen as an anode, while a double layer capacitive electrode forms the cathode in a non-aqueous electrolyte, thus offering intermediate energy and power density compared to batteries and supercapacitors.2
,
3 Recently, sodium based hybrid ion capacitors have been explored due to the large abundance and low cost of sodium.4
,5 Herein, we report the fabrication of an efficient hybrid sodium ion capacitor, in which the cathode, anode and separator are derived from a single precursor, coconut sprout (CS). Graphene like carbon derived from CS, employed as intercalating anode, exhibits a specific capacity of 181 mAh g-
1, while the high surface area (BET surface area of 2000 m2g-1) activated carbon (obtained by KOH activation of CS) cathode delivers a capacity of 90 mAh g-
1
vs. Na/Na+. Full cell hybrid ion capacitor fabricated combining the two electrodes with optimized mass loading, using CS-derived separator, delivers an energy density of 88.12 Wh kg-1 at a power density 273.26 W kg-1, when cycled in a potential window of 1.5 -4.0 V. The fabricated device retains 65% of its initial capacity after 5000 cycles, when cycled at a high current density of 1A g-1. Most interestingly, the spongy sprout separator showed excellent chemical and mechanical stability even after 10000 cycles of charge and discharge. Several factors including the use of low cost single precursor, facile synthesis route, minimal environmental impact, makes our approach promising towards designing eco-friendly and green electrochemical storage systems.

References

(1) Amatucci, G. G.; Badway, F.; Du Pasquier, A.; Zheng, T. An Asymmetric Hybrid Nonaqueous Energy Storage Cell. J. Electrochem. Soc.
2001, 148 (8), A930.
(2) Ding, J.; Wang, H.; Li, Z.; Cui, K.; Karpuzov, D.; Tan, X.; Kohandehghan, A.; Mitlin, D. Peanut Shell Hybrid Sodium Ion Capacitor with Extreme Energy-Power Rivals Lithium Ion Capacitors. Energy Environ. Sci.
2015, 8 (3), 941–955.
(3) Sivakkumar, S. R.; Pandolfo, A. G. Evaluation of Lithium-Ion Capacitors Assembled with Pre-Lithiated Graphite Anode and Activated Carbon Cathode. Electrochim. Acta
2012, 65, 280–287.
(4) Ding, J.; Hu, W.; Paek, E.; Mitlin, D. Review of Hybrid Ion Capacitors : From Aqueous to Lithium to Sodium. Chem. Rev.
2018, 118, 6457–6498.
(5) B. Babu and M. M. Shaijumon, J. Power Sources 353, 85-94 (2017)
Structural and Electrochemical Characterization of Thin Film Li2MoO3 Cathodes
Authors: Self Ethan Craig , Zhang Yiman , Kercher Andrew , Phillip Nathan Dale , Delnick Frank M. , Nanda Jagjit 
Published: February 2020

Development of low-cost cathodes with high energy density and long cycle life is critical to enable advanced Li-ion batteries for transportation applications. When charged beyond 4.3 V vs. Li/Li+, most lithium-transition metal oxides (e.g., LiMO2, M = Ni, Mn, Co) undergo irreversible structural changes with concomitant oxygen gas evolution, resulting in irreversible capacity loss and voltage fade during cycling. One strategy to improve cathode stability at high states of charge is to design composite structures containing LiMO2 as the primary Li storage site and Li2MoO3 as a structural stabilizing unit (i.e., cathodes with the formula xLi2MoO3•(1-x)LiMO2). In this regard, Li2MoO3 possesses several attractive properties including a stable oxygen framework (up to 4.8 V vs. Li/Li+) and the ability to reversibly cycle 1 Li per formula unit.
To aid the development of Mo-based composite cathodes, the phenomena occurring at the cathode/electrolyte interface (e.g., Li transport, electrolyte decomposition, charge transfer, etc.) during battery cycling must be well-understood. However, interpreting in-situ and ex-situ data collected with traditional slurry cast electrodes is oftentimes complicated by the presence of conductive carbon and polymer binder which may participate in side reactions with the electrolyte and/or produce signals that overlap with the desired signal from the active material. To resolve this issue, radio frequency (RF) sputtered thin film cathodes composed entirely of active material represent a model system to study the electrode/electrolyte interface. In addition to eliminating unwanted signal arising from inactive components, sputtered thin films have a planar surface which greatly simplifies interpretation of AC impedance spectroscopy data.
The present work describes the preparation and characterization of Li2MoO3 thin film cathodes shown in Figure 1a. When cycled in a conventional liquid carbonate electrolyte (Figures 1b and 1c), the cathodes exhibited an initial reversible capacity of 166 mAh/g which rapidly faded to 99 mAh/g after 20 cycles. In comparison, all-solid-state Li2MoO3/Lipon/Li thin film batteries showed excellent stability with negligible capacity fade during cycling. As will be discussed, these differences are related to the nature of the cathode/electrolyte interface. This presentation will provide additional findings from X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), vibrational spectroscopy, and AC impedance spectroscopy. Overall, these results provide important insights on the fundamental interfacial phenomena that govern cathode performance.

Acknowledgements

This research has been supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies, of the U.S. Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) Program.

Figure 1
Development of Selenium Substituted Lithium Titanium Sulfide Materials (Li2TiSexS3-x) As Positive Electrodes for Li-Ion Batteries
Authors: Celasun Yagmur , Colin Jean François , Peralta David , Martinet Sebastien 
Published: February 2020

Rock salt materials are experiencing a comeback and being reconsidered as promising positive materials for lithium ion batteries due to recent advancements. This reappraisal has been accelerated by the latest studies1 which have shown that the overlithiated compositions could provide much higher capacities (> 250 mAh/g) than the stoichiometric compositions. As the material becomes richer in lithium, the probability for Li+ ions finding an available space in the lattice increases due to the percolating network that is formed through the lithium diffusion channels2. Thus, greater material capacities can be achieved.
Lithium titanium sulfide (Li2TiS3), which has been reported by Sakuda et al., demonstrated excellent capacity owing to the multi electron redox reactions3. By utilizing both sulfur and titanium redox, more than two lithium ions were reversibly intercalated through the structure and the capacity reached 425 mAh/g upon cycling between 3 V and 1.5 V vs Li+/Li. Although Li2TiS3 possesses such a large reversible capacity, its cycling stability is rather poor. Therefore, new approaches are necessary to enhance its cyclability. Partial substitution mechanisms are promising solutions in this issue.
Here, we propose Se-substituted lithium titanium sulfide materials (Li2TiSexS3-x), which have recently been patented. By applying our patented synthesis process, Se substituted materials showed better cycling stability. For comparison, we will provide a comprehensive study of pure and substituted materials through fine characterization tools (XRD, SEM, EDX, ex situ and in situ XRD) in order to examine electrochemical and structural properties as well as the capacity degradation mechanism.

References:

[1] N. Yabuuchi, Proc. Natl. Acad. Sci., 112 (25), 7650–7655 (2015)
[2] J. Lee, Science, 343 (6170), 519-521 (2014)
[3] A. Sakuda, Sci. Rep, 4 (1), 4883 (2015)

Figure 1
"Dead" Lithium: Interface Evolution and Characterization
Authors: Tewari Deepti , Perumaram Rangarajan Sobana , Mukherjee Partha P. 
Published: February 2020

During stripping of lithium metal anode, some fraction of lithium becomes detached from the lithium anode. This remnant lithium is electrochemically inactive and is called “dead” lithium. This leads to irreversible loss of capacity and lowers the Coulombic efficiency of the battery. The presence of dead lithium also affects the transport of lithium ions in the electrolyte which can potentially alter the conditions for plating during subsequent cycling.
The aim of this work is to identify the dominant mechanisms responsible for the formation of dead lithium as well as quantify the amount of dead lithium. Mesoscale modeling along with experimental corroboration to probe the evolution of the interface between lithium anode and liquid electrolyte during discharging will be presented. The effect of ionic diffusion in electrolyte, surface diffusion of lithium and electrochemical reaction rate kinetics are considered.

Figure 1
Microstructure Simulation and Virtual Material Design of Electrospun Gas Diffusion Layers for Polymer Electrolyte Membrane Fuel Cells
Authors: Balakrishnan Manojkumar , Fahy Kieran F. , Schulz Volker P , Bazylak Aimy 
Published: February 2020

Polymer electrolyte membrane fuel cells (PEM-FC) are promising electrochemical devices for the production of electrical power without local emissions of CO2. In the PEM-FC, hydrogen and oxygen electrochemically react to produce water and heat. The generated liquid water is necessary for protonic conductivity in the electrolyte membrane, but excess liquid water hinders reactant gas diffusion from the gas flow channels to the reaction sites. Therefore, effective water management is vital for achieving high power density with PEM-FCs. In this context, a well-designed gas diffusion layer (GDL) must simultaneously facilitate the transport of reactants, excess liquid water, electrons, and heat.
Here, we present a characterization of electrospun gas diffusion layers (eGDL) as a new material used in PEM-FCs [1]. Compared to conventional GDL materials such as carbon paper (e.g. Toray-H-60) with fiber diameters in the range of 7 to 10 micrometers [2], the fiber diameters of the eGDL materials are in the range of 150 to 600 nanometers only.
While the improved performance of the PEM-FC with eGDLs has been shown in experiments [1], we describe the eGDL properties based on its micro-structure. The basis of this characterisation is the virtual material design as in [3,4]. Based on 2D microscopic images of the eGDL, its 3D structure is reconstructed as stochastically overlapping straight fibers with appropriate orientation. Given the bulk geometric properties of the fibers, we calculate single and multiphase properties by solving the appropriate partial differential equations. Examples of these parameters are the thermal and electrical conductivity, the diffusivity, and the capillary pressure-saturation curves.
Finally, the determined parameters are used as inputs to a 1D PEM-FC model and the modeling results are compared to experimental data.

REFERENCES

[1] Chevalier, S.; Lavielle, N.; Hatton, B. D.; Bazylak, A. (2017). Novel electrospun gas diffusion layers for polymer electrolyte membrane fuel cells: Part I. Fabrication, morphological characterization, and in situ performance, Journal of Power Sources, Vol. 352, 272–280. doi:10.1016/j.jpowsour.2017.03.098
[2] Mathias, M.; Roth, J.; Fleming, J.; Lehnert, W.L. (2003). Handbook of Fuel Cells: Fundamentals, Technology, and Applications. John Wiley & Sons, Hoboken, NJ.
[3] Schulz, V. P.; Becker, J.; Wiegmann, A.; Mukherjee, P. P.; Wang, C.-Y. (2007). Modeling of Two-Phase Behavior in the Gas Diffusion Medium of PEFCs via Full Morphology Approach, Journal of The Electrochemical Society, Vol. 154, No. 4, B419. doi:10.1149/1.2472547
[4] Wargo, E. A.; Schulz, V. P.; Çeçen, A.; Kalidindi, S. R.; Kumbur, E. C. (2013). Resolving macro- and micro-porous layer interaction in polymer electrolyte fuel cells using focused ion beam and X-ray computed tomography, Electrochimica Acta, Vol. 87, 201–212. doi:10.1016/j.electacta.2012.09.008

Figure 1
Correlative Multiscale Tomography on Inert Supported Solid Oxide Fuel Cells
Authors: Wankmüller Florian , Russner Niklas , Weber André , Meffert Matthias , Schmieg Johannes , Störmer Heike , Lupetin Piero , Gerthsen Dagmar , Ivers-Tiffée Ellen 
Published: February 2020

The solid oxide fuel cell (SOFC) offers a great potential for stationary energy conversion applications because of its high combined heat and power efficiency. It is of great interest to understand performance relevant aspects of both material selection and manufacturing optimization. A design, which is made by co-sintering of inert substrate and functional layers, offers great possibilities for further methodological development. Findings can be transferred to different cell concepts. To understand and link fabrication parameters to the cell performance and identify aging mechanisms, sophisticated investigation of the 3D microstructure is necessary.
This contribution will demonstrate how advanced correlative multiscale tomography can be used to identify microstructural parameters ranging from millimeter to nanometer scale. We combine optical microscopy (OM), X-ray computed tomography (μ-CT), focused ion beam – scanning electron microscopy (FIB-SEM) tomography and energy dispersive X-ray spectroscopy - scanning transmission electron microscopy (EDXS-STEM). The resulting microstructure data can be used to visualize performance critical cell areas such as inhomogeneities and secondary phases. In addition, pore and tortuosity distributions obtained from data of different length scales allow modeling of gas diffusion losses of all cell layers. This exemplifies how correlative tomography helps to understand specific contributions to overall cell performance.

Figure 1