bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Printed Poly-Si TFTs on Paper for Beyond Plastic Electronics
Authors: Ishihara Ryoichi , Trifunovic Miki , Sberna Paolo , Shimoda Tatsuya
Published: February 2020

Solution process has received many attentions in recent years because of low-cost manufacturability of flexible electronic devices owing to the additive process. Organic and metal-oxide semiconductors can be printed at low-temperature however carrier mobility and reliability of TFTs using those materials are still much inferior than those for silicon. Silicon as the base material, on the other hand, has advantages in terms of high-mobilities for the both of electron and holes, chemical and electrical stability, and low-power consumption by CMOS circuit configuration.

Silicon can be printed using liquid silicon ink, which is a mixture of polymerized cyclopentasilane (CPS) and a solvent [1]. However, low-temperature formation and fabrication of polycrystalline-Si (poly-Si) and transistors on top of low-cost flexible substrates, such as paper, were outstanding challenges.

In this paper, we review a novel method that forms poly-Si patterns directly on paper using the same liquid silicon with doctor-blade coating and local irradiation of excimer-laser with room temperature process [2]. We review also the process and electrical properties of poly-Si TFTs fabricated on the paper [3]. Both p- and n-channel poly-Si TFTs were fabricated directly on top of paper with field-effect mobilities of 6.2 cm2/Vs and 2.0 cm2/Vs, respectively. Owing to the low-cost, biodegradable nature of paper, and superior electrical performance and reliability and biocompatibility of silicon, this technique will break-though the printed electronics by enabling applications such as fast printed electronics that are inexpensive, fully-recyclable, biodegradable and even edible.

[1] T. Shimoda, et al., “Solution-processed silicon films and transistors” Nature 440, 783-786 (2006).

[2] M. Trifunovic, T. Shimoda and R. Ishihara, “Solution-processed polycrystalline silicon on paper”, Appl. Phys. Lett. 106, 163502 (2015)

[3] M Trifunovic, PM Sberna, T Shimoda, R Ishihara, “Solution-based polycrystalline silicon transistors produced on a paper substrate”, npj Flexible Electronics 1 (1), 12 (2017)
Electrical and Reliability Properties of Tungsten Doped Indium Based Oxide Thin Film Transistor Fabricated on Polyimide Substrate
Authors: Yu Min-Chin , Liu Po-Tsun , Ruan Dun-Bao , Li Zhen-Hao , Chiu Yu-Chuan , Gan Kai-Jhih , Chien Ta-Chun , Chen Yi-Heng , Kuo Po-Yi , Sze Simon M.
Published: February 2020

In the recent research, a novel type of dopant element in the indium based oxide thin film transistor: tungsten was proposed to replace the expensive and rare gallium element for its low price and even higher oxygen bond dissociation energy, which may further improve the device instability and keep the carrier mobility with a low temperature process at the same time. Therefore, the tungsten doped channel material is more suitable for the flexible device than other transparent amorphous oxide semiconductors. In this work, the devices with tungsten doped channel material were manufactured on a polyimide substrate, which exhibit an acceptable electrical performance and reliability characteristic without a high temperature treatment. In addition, a bending test was also carried out to check the stability for the flexible device.
Practical Solar Hydrogen Production Using Z-Scheme Photocathodes
Authors: Tsao Chun-Wen
Published: February 2020

Natural processes such as photosynthesis serve as an inspiration for the vision of sustainable development. Particularly, converting water into hydrogen by using solar energy offers a practical solution to the ever-increasing global energy demand. Here, we developed a Z-scheme heterostructure photocathode for constructing photoelectrochemical cells to produce hydrogen from water. The samples were prepared by successively depositing Au particles and Cu2O nanocrystals on CuO films. For CuO-Au-Cu2O, the embedded Au can promote electron transfer from the conduction band of CuO to the valence band of Cu2O, a typical Z-scheme charge transfer scenario imitated from the natural photosynthesis. This vectorial charge transfer resulted in the situation that the photoexcited electrons accumulated at the conduction band of Cu2O (-1.83 V vs. NHE) and holes accumulated at the valence band of CuO (+0.88 V vs. NHE). With the substantially high reducing power and enhanced charge separation, CuO-Au-Cu2O photocathodes showed superior hydrogen production rates over pure CuO and CuO-Au.
Tailoring Electrolyte Specifications for Graphite/NMC811-Based Lithium Ion Batteries
Authors: Beltrop Kolja , Klein Sven , Nölle Roman , Qi Xin , Winter Martin , Placke Tobias
Published: February 2020

In order to increase the energy density of lithium-ion batteries (LIB) one promising approach is rooted in the increase of the nickel content in layered oxide cathode materials (LiNixMnyCo1-x-yO2, x ≥ 0.6, LiNMC) for an application as positive electrode due to the high specific discharge capacity at moderate upper cutoff voltages below 4.4 V vs. Li/Li+.[1, 2] However, the insufficient cycling stability as well as significant safety concerns restricted this material class from industrial application so far. For that reason, new electrolyte compositions including specifically designed additives are of great importance to enable a sufficient electrochemical performance of Ni-rich NCM materials.[3]

In this work, we introduce a low molecular weight, low cost and non-toxic chemical compound as electrolyte additive for the application in graphite/LiNi0.8Mn0.1Co0.1O2 (NMC811) cells.[4] The addition of only 0.5 wt.% of the additive into the control electrolyte (1M LiPF6 in EC / EMC 3:7, by weight) significantly increases the reversible capacity as well as the 1st cycle Coulombic efficiency (CE) improving the capacity retention of the standard full cell system between 2.8 - 4.3 V. Irreversible lithium loss in the negative electrode was found to be the predominant factor for the full cell capacity fade and the poor cycling performance of the control electrolyte. Inductively coupled plasma-mass spectrometry (ICP-MS) and X-ray photoelectron spectroscopy (XPS) analysis reveals the contribution of the electrolyte additive in the solid electrolyte interface (SEI) formation on the negative electrode as well as in the cathode electrolyte interface (CEI) formation on the positive electrode. As a result, less active lithium loss during cycling is present in the additive containing electrolyte which leads to an impressive increase in capacity retention of 77%. In addition, a comprehensive performance study of state of the art electrolyte additives such as triphenylphosphine (TPP), vinylene carbonate (VC) and diphenyl carbonate (DPC) is presented and compared to the invented electrolyte additive, demonstrating the outstanding working ability of this compound in graphite/NMC811 cells. To the best of our knowledge the presented cycling results outperform the so far reported electrolyte additives in the field.

Reference:

[1] J. Kasnatscheew, M. Evertz, R. Kloepsch, B. Streipert, R. Wagner, I. Cekic Laskovic, M. Winter, Energy Technology, 5 (2017) 1670-1679.

[2] H.-J. Noh, S. Youn, C.S. Yoon, Y.-K. Sun, Journal of Power Sources, 233 (2013) 121-130.

[3] A.M. Haregewoin, A.S. Wotango, B.J. Hwang, Energy & Environmental Science, 9 (2016) 1955-1988.

[4] K. Beltrop, S. Klein, R. Nölle, A. Wilken, J.J. Lee, J. Reiter, L. Tao, C. Liang, M. Winter, X. Qi, T. Placke, Chemistry of Materials, (2018), submitted.

Figure 1
Porous Amorphous Electrocatalyst Development for Active and Durable Oxygen Evolution
Authors: Hu Fei , Shen Xiaochen , Pan Yanbo , Peng Zhenmeng
Published: February 2020

Material novelty is momentous for electrocatalyst in striding into a renewable energy era. Oxygen evolution reaction (OER) is of great significance for hydrogen production via water electrolysis, but has a high energy barrier that limits the energy conversion efficiency. Herein we report a highly-efficient and long-term durable NiFePB OER electrocatalyst, which composes of unique porous amorphous conductive solids with finely tuned nonmetal elements. The NiFePB phase formation is confirmed with X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) characterizations determine a porous amorphous structure. The outstanding metallic conductivity and corrosion resistance properties are simulated with density functional theory (DFT) calculations. Benefiting from these unique features, the NiFePB exhibits an extraordinarily low overpotential of 197 mV to reach an OER current density of 10 mA/cm2 and 233 mV to reach 100 mA/cm2 under chronopotentiometry condition, with the Tafel slope harmoniously conforming to 34 mV/dec. The catalyst also has an impressive long-term stability, evidenced by a limited activity decay for more than 50-h in a wide current density range from 10 to 200 mA/cm2. This work strategically directs a way for heading up a promising energy conversion alternative.
(Invited) Tuning Ion Mobility in Solid Electrolytes Via Lattice Disorder
Authors: Kim Kwangnam , Siegel Donald J
Published: February 2020

Historically, the ionic conductivity of solids has been insufficient to supplant liquid electrolytes in battery applications. Very recently, however, a small number of solids with ionic conductivities comparable to that of liquids have been identified. The discovery of these fast ion conductors has advanced the prospects for realizing solid-state batteries. Nevertheless, additional study of these materials has, in essentially all cases, unearthed other shortcomings (stability, Li penetration, etc.), suggesting that the discovery of alternative solid electrolytes (SE) remains an important pursuit.

A fundamental question in the identification of new SEs is ‘what chemical/mechanical/structural features promote high ion mobility?’ We hypothesize that lattice disorder represents one such feature. The anti-perovskites (AP) present an ideal venue to explore the connection between disorder and ion mobility: the degree of disorder in the APs can be systematically tuned via atom substitution, yet the relative simplicity of the structure allows for a comprehensive characterization of ion migration pathways.

Here, we systematically probe the connection between ionic mobility and lattice disorder across a series of 24 model APs. Our calculations reveal that ‘disorder tuning’ provides a pathway to higher ionic conductivity. More specifically, a strong correlation is observed between the degree of lattice disorder and the minimum migration barrier for percolating ion migration: compounds with the largest disorder exhibit the lowest barriers for ion migration, independent of the migration mechanism (vacancy or interstitial). At the same time, the energetic spread between the largest and smallest migration barriers for a given compound increases with increasing disorder. Nevertheless, a higher degree of disorder also correlates with diminished thermodynamic stability, signaling a tradeoff with ionic mobility. Thus, realizing higher mobility will benefit from the development of strategies to kinetically stabilize disordered phases.
Additively Manufactured Solid-State Ion Conductors for Resistive Switching Devices
Authors: Tsui Lok-kun , Plumley John Bryan , Peng Thomas , Garzon Fernando H
Published: February 2020

Additive manufacturing of solid-state ion conductors opens the possibility to fabricate at low-cost novel electrochemical devices as an alternative to clean room techniques. This would promote their use for small-scale production or rapid prototyping. Memristive devices based on conductive bridging are a promising technology for next generation memories, neuromorphic computing, and reconfigurable electronic switches.1,2 Electrochemically driven growth of a metal filament from the cathode to the anode through a solid-state ionic conductor is used to switch the device from a low conductivity state to a high conductivity state. They are of particular interest in satellite electronics due to their innate radiation hardness compared to traditional transistor-based devices.

We have printed Pt/AgI/Ag electrochemical cells (Figure 1(a), inset) as a proof of concept that such devices can be produced by additive manufacturing. The AgI electrolyte is deposited by computer controlled extrusion of a paste and the electrodes are formed by initially by vapor deposition and subsequently by inkjet printing. The latter demonstrates a completely additively manufactured device. During filament formation AgI acts as an Ag+ ion conductor, Pt is the cathode, and Ag is the anode. The current of the device at a fixed applied voltage is found to increase by three orders of magnitude (Figure 1(a)) as the conductive bridging is completed. Cyclic voltammetry was also able to demonstrate reversible switching between the high and low conductivity states (Figure 1(b)). Finally, impedance measurements were performed to evaluate the conductivity of the printed AgI electrolyte as a function of temperature.

References

I. Valov and M. N. Kozicki, J. Phys. D. Appl. Phys., 46, 74005 (2013).

A. H. Edwards, H. J. Barnaby, K. A. Campbell, M. N. Kozicki, W. Liu, M. J. Marinella, Proc. IEEE, 103, 1004–1033 (2015).

Figure 1 (a) Resistance decreases three orders of magnitude during filament formation when bridging is complete at point X. A schematic of the cell is provided in the inset. and (b) Reversible switching between a high resistance state and a low resistance state by cyclic voltammetry with a Pt/AgI/Ag cell.

Figure 1
Influence of Ca Doping on the Performance of Ruddlesden-Popper Oxides Sr3.2-XCaxLn0.8Fe1.5Co1.5O10-δ as Cathode Materials for It-SOFCs
Authors: Padmadas Padmasree K , Lai Ke-Yu , Manthiram Arumugam
Published: February 2020

Solid oxide fuel cell (SOFC) is an attractive electrochemical device for energy conversion with high efficiency and fuel flexibility at high operating temperatures (~1000 °C). Current operating temperatures of SOFC technology limit its wide commercialization due to the selection of materials used and degradation of cell components. This challenge has generated enormous interest in SOFCs operating at intermediate temperatures (600 – 800 oC). However, the catalytic activity of the conventional La1-xSrxMnO3 perovskite cathode drops significantly at temperatures < 800 °C. Mixed ionic-electronic conducting perovskites are widely investigated as cathodes for SOFCs due to their high catalytic activity for oxygen reduction reaction (ORR) at intermediate operating temperatures. Cobalt-based perovskite oxides exhibit good mixed ionic-electronic conductivity and catalytic activity at 600 – 800 oC, but they suffer from a huge thermal expansion mismatch between the electrolyte and electrode. Another class of materials with mixed ionic and electronic conducting property and catalytic activity for ORR is the perovskite-related intergrowth oxides belong to the Ruddlesden-Popper (R-P) series. Here we present R-P oxides of the n = 3 series Sr3.2-xCaxLn0.8Fe1.5Co1.5O10-δ with x = 0 and 0.4 and Ln = La, Pr, and Nd as potential cathodes for intermediate temperature SOFCs. Specifically, the effects of Ca substitution for Sr on the crystal chemistry, oxygen content, thermal expansion coefficient (TEC), and electrocatalytic activity in SOFC are presented. The substitution of Ca for Sr in Sr3.2-xCaxLn0.8Fe1.5Co1.5O10-δ enhances the stability of phase at the operating temperatures and decreases the amount of oxygen loss on heating. Comparing different lanthanides with and without Ca in Sr3.2-xCaxLn0.8Fe1.5Co1.5O10-δ, the Ln = Nd samples exhibit superior cathode performance which is ascribed to the high concentration of oxygen vacancies. Among the different compositions studied, the composite cathode Sr2.8Ca0.4Nd0.8Fe1.5Co1.5O10-δ + GDC exhibits an enhanced performance with good phase stability due to high oxygen vacancy concentration and enhanced oxide-ion transport.
Redox Stability of La0.6Sr0.4Fe0.9Sc0.1O3-Δ for a Solid Oxide Cell Interconnector
Authors: Kim Sun-Dong , Kwak Minjoon , Choi Hyun-Jong , Kim Tae Woo , Seo Doo-Won , Woo Sang-Kuk
Published: February 2020

A ceramic interconnector of a solid oxide cell (SOC) should require high phase stability and conductivity in a redox environment. Due to these limitations, only a few materials were found to meet the usage requirement as SOC interconnector. Under various synthetic conditions, La0.6Sr0.4Fe1-xScxO3-δ (LSFSc) was synthesized for the purpose of introducing a redox stable and electrically conductive ceramic interconnector. The crystalline phases of LSFSc are stable when the solution pH is low (pH=2), and the calcination temperature is sufficiently high (T=1200ºC). From the XPS analysis, it is accepted that incorporation of Sc in the B site of La0.6Sr0.4FeScO3-δ lattice further stabilizes its structural stability under reducing conditions. When the Sc concentration exceeds 10 mol%, phase stability of La0.6Sr0.4Fe1-xScxO3-δ was obtained. Figure 1 shows the ASR variations of ceramic interconnectors based on LaFeO3 doped at A-site with Sr and B-site with Sc in various redox environments. The electrical conductivity of La0.8Sr0.2FeO3-δ is remarkably low at both oxidation and reduction atmospheres due to the high area specific resistance. However, the ASR of La0.6Sr0.4FeO3-δ is less than half of La0.8Sr0.2FeO3-δ when exposed to air at one side and is exposed to H2 on the opposite side. This is one of the main reasons why we selected the composition as the basic crystal structure. However, La0.6Sr0.4FeO3-δ shows big augment due to the decomposition at reduction atmosphere. Moreover, the instability against high relative humidity (RH) is the main downside of La0.6Sr0.4FeO3-δ. For these reasons, it is difficult to employ La0.6Sr0.4FeO3-δ
as an interconnector material. Among the proposed materials, La0.6Sr0.4Fe0.9Sc0.1O3-δ exhibited the most desirable performances at the various gas conditions for 1000 h. Therefore, La0.6Sr0.4Fe0.9Sc0.1O3-δ is considered to be the most stable composition for redox stable and electrically conductive ceramic interconnectors for solid oxide cells.

Figure 1. The ASR variations of the La0.6Sr0.4Fe1-xScxO3-δ specimen depending on gas atmosphere and operation time.

Figure 1
Comparison of H2s Poisoning for Proton Conducting SOFC Versus Oxide Ion Conducting SOFC
Authors: Sun Shichen , Cheng Zhe
Published: February 2020

Previous studies indicated that the Ni-based cermet anode for proton conducting solid oxide fuel cells (PC-SOFC) seemed to have better tolerance against poisoning by low-ppm-level hydrogen sulfide (H2S) compared to conventional oxide-ion conducting SOFC, but the detail and the origin for such a difference are not known. In this study, an in-depth investigation was carried out to reveal the differences in H2S poisoning behavior for PC-SOFC (based on BaZe0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) electrolyte and Ni-BZCYYb cermet anode) versus conventional oxide ion conducting SOFC (based on yttria-stabilized-zirconia (YSZ) electrolyte and Ni-YSZ cermet anode) using both electrolyte supported full cells and anode symmetrical cells from 750 to 450oC. In addition, a dense Ni-BZCYYb composite pellet to simulate the cermet anode was exposed to hydrogen fuel with ppm-level H2S and then characterized using tools such as XRD, SEM/EDS, and secondary ion mass spectroscopy (SIMS). The implications of the results on the sulfur poisoning mechanism as well as the overall anode hydrogen electrochemical oxidation process for PC-SOFC, including the potential electrocatalytic role proton conducting oxide electrolytes might play will be discussed, and the directions for future work including the use of cells with patterned metal electrodes will be pointed out.
Development of High Performance Metal-Supported Solid Oxide Electrolysis Cells
Authors: Wang Ruofan , Dogdibegovic Emir , Lau Grace , Tucker Michael C
Published: February 2020

Hydrogen as an energy carrier has the highest energy/weight ratio, and therefore it has been advocated as the desired fuel for automotive power, auxiliary power, stationary power generation, and also as an energy storage medium. Among various hydrogen generating methods, high temperature electrolysis (HTE) of water using solid oxide electrolysis cells (SOECs) has attracted substantial attention over the last decade due to its high efficiency of conversion and low energy consumption.

To date, extensive effort has been devoted to the development of SOECs and promising results have been shown.1,2 However, while most of SOECs are based on an anode-supported cell (ASC) structure, only limited research on metal-supported SOECs is reported.3,4 Compared with conventional ASC type SOECs, metal-supported solid oxide electrolysis cells (MS-SOECs) have unique advantages due to low cost of fabrication, high mechanical strength, good redox stability, and excellent thermal cycling resistance.5,6 Because of these characteristics, MS-SOECs are considered as a promising solution for intermittent and mobile electrolysis applications.

In this work, symmetric-structure MS-SOECs with stabilized zirconia electrolyte are developed at LBNL. Nanostructured cathode and anode are fabricated by infiltrating catalysts on both steam and oxygen electrodes. The cells are tested in the temperature range of 650 to 800 ◦C, with steam content between 3-75 vol%. Our MS-SOECs show the highest performance for the cells with zirconia-based electrolyte (Figure 1), to the best of our knowledge. At 1.3 V (thermoneutral voltage) and 50 vol% steam content, the measured current densities were 4.8 A/cm2 at 800 ◦C, 3.1 A/cm2 at 750 ◦C, 2.0 A/cm2 at 700 ◦C, and 1.2 A/cm2 at 650 ◦C. This performance was achieved by optimizing the catalyst chemistry, catalyst arrangement, and infiltration process. In order to study the effects of the cell fabrication process, the electrochemical performance at various steam contents and overpotentials is analyzed, and the corresponding microstructures are examined. The high cell performance shows a great potential of MS-SOEC technology, and the insight from these experiments will provide guidance for further research and development.

1S.D. Ebbesen, S. H. Jensen, A. Hauch, and M. B. Mogensen, Chem. Rev., 114(21), 10697-10734 (2014).

2M. A. Laguna-Bercero, J. Power Sources, 203, 4-16 (2012).

3T. Chen, Y. Zhou, M. Liu, C. Yuan, X. Ye, Z. Zhan, and S. Wang, Electrochem. Commun., 54, 23-27 (2015).

4G. Schiller, A. Ansar, M. Lang, and O. Patz, J. Appl. Electrochem., 39(2), 293-301 (2009).

5M. C. Tucker, J. Power Sources, 195(15), 4570-4582 (2010).

6M. C. Tucker, Energy Technol., 5(12), 2175-2181 (2017).

Figure 1. Performance of a metal-supported solid oxide electrolysis cell (a) at 700 ◦C with 3%, 25%, 50% and 75% steam contents in the cathode, and (b) with 50% steam content in the cathode at 650, 700, 750 and 800 ◦C.

Figure 1
Anode Configuration of Li Metal for Lithium Sulfide Full Cell for High Energy Li-S Battery
Authors: Jung Yongjo , Kang Byoungwoo
Published: February 2020

Since Li-ion batteries (LIBs) have been commercialized in the early 1990s, LIBs have become popular power sources for portable electronics due to their high gravimetric and volumetric energy density. Recently, the use of Li-ion batteries has been extended to large scale applications such as electric vehicles (EVs) and energy storage systems. For powering electrical vehicles, LIBs require high gravimetric and volumetric energy density, superior safety, and low cost. To meet these requirements in LIBs, there are several approaches. Among them, the use of S as a cathode material can be a very promising approach because sulfur can achieve 4 ~ 5 times higher energy density than conventional cathode materials such as LiCoO2 and is abundant and then cheap. However, the use of S needs the source of Li in a cell such as Li-metal or lithiated materials as an anode material. For example, the use of Li metal in Li-S cell is not trivial because of not only serieous safety issues origianted from the dendritic growth of Li but also poor couloumbic efficiency that can require excess amount of Li metal. The excess amount of Li metal under a limited cell volume needs additional sapce for Li metal leading to poor volumetric energy density. This requirement can make a limited utilization of Li-S.

As an alternative approach, Li2S can be considered as a cathode material for Li-S cell. Li2S as a cathode can achieve a little lower energy density than S but still higher than the conventional electrode materials. Moreover, the use of Li2S can extend the choice of anode materials from a graphite to a silicon to Li metal without any limitations because large amount of available lithium ions can be provided from Li2S. When Li metal as a anode material in the same volume of the Li2S cell can be used, the required space for Li metal in the Li2S cell will be decreased compared to Li-S cell because of additional Li can be provided from Li2S. Less required space for Li metal in the Li2S cell implies that additional Li2S in the saved space can be loaded and then volumetric energy density can be increased.

In this talk, we will discuss the use of Li metal as an anode material in Li2S cell and the factors affecting the nucleation and growth of Li metal on the electrode. Furthermore, we will talk about electrochemical performances of Li2S full cell at different conditions of Li metal.
Micro-Spherical Na0.65[Ni0.17Co0.11Mn0.72]O2 Cathode Material for High-Performance Sodium-Ion Batteries
Authors: Yu Tae-Yeon , Sun Yang-Kook
Published: February 2020

P2-type layered oxides have been considered promising candidates as cathodes for sodium-ion batteries (SIBs) because of their high capacity and high rate capability. However, because of the difficulty involved in forming hierarchical microstructures, it remains challenging to develop high energy density P2-type layered oxides with good electrochemical performance and high electrode density. In this study, we demonstrate the feasibility of P2-type Na0.65[Ni0.17Co0.11Mn0.72]O2 as a efficient cathode material for high energy density SIBs by synthesizing a micron-sized hierarchical structure via the co-precipitation route. The as-prepared P2-type microsphere cathode constructed from nanoscale primary particles provides a sufficient interface between the electrodes and the electrolyte solution, which enables to shorten the transport pathways for Na+ ions and electrons. Simultaneously, the hierarchical microstructure enhances the structural stability and high tap density. From these merits, the proposed P2-type microsphere Na0.65[Ni0.17Co0.11Mn0.72]O2 shows a high discharge capacity of 187 mA h g-1 at 12 mA g-1 and an exceptional cycle retention of 74.7% after 500 cycles, even at the high current density of 600 mA g-1. In addition, the high tap density of this P2-type microsphere enhances the density of composite cathodes, which translates to a high volumetric energy density of 340 W h L-1 based on the overall volume of the cathode active mass and the aluminum foil current collector.
A Strategy to Solve the Problem of Initial Charge Irreversibility in P2-Type Layered Cathode Materials for Sodium-Ion Battery
Authors: Kim Seong In , Park Geun-gyung , Lee Da-Yeon , Eom Ji-Yong
Published: February 2020

Na-ion batteries are currently the focus of significant research activity due to the relative abundance of sodium and its consequent cost advantages. Thus, enormous efforts have been made to improve the electrochemical performance of SIBs through the development of novel cathode materials.

According to the previous literatures, P2-type layered cathode materials for SIBs have suffered from their low initial coulombic efficiency, which inevitably requires the pre-sodiation of carbon anode materials under full cell systems. In this regard, we focused on how to increase their initial charge capacity with sacrificial salts in the level of electrode fabrication. Thus, in the present study, we suggest new electrode fabrication process with sacrificial salts to reduce the high initial irreversible.
Layered Li-Rich Oxide Cathode with High Rate Capability By Reductive Treatment
Authors: Jung Dae Soo
Published: February 2020

Layered Li-rich oxide cathode materials (denoted as OLO), such as Li1+xMn1-x-y-zNiyCozO2 (x > 0), have attracted recent research interest because these OLO materials offer high capacity performance (> 250 mAh g–1). However, it is still difficult to use these materials in commercial cathodes because their rate capability and capacity decrease with repetitive cycle life as a result of low electrical conductivity and phase transformations. Accordingly, there have been many studies focusing on structure stabilization and enhancement of their electrical conductivity, such as through substitution with Mg, Zn, Mo and Cr ions and surface coating with Al2O3, TiO2 and Li4Ti5O12. We previously reported on the stabilization of these structures and enhancing the electrochemical performance of Li-rich cathode materials via substitution and coating. There have also been recent attempts to find new approaches for surface modification such as through the use of heterostructures. S. Lee et al. reported spinel cathode material coating on layered cathode materials, which enhanced their electrochemical performance due to the spinel structure which functions as a conductive agent and prevents side reactions. J. Cho et al. also reported heterostructured cathode materials such as spinel-layered core-shell materials and Ni-rich/Li-rich core-shell materials. Y-K. Sun et al. demonstrated a concentration-gradient shell (CGS) cathode material, featuring different concentrations of transition metals (Ni, Co and Mn) at different layers in the material. While these studies showed outstanding enhancement for stabilization of structure and electrical conductivity with good electrochemical performances, they all required complex syntheses to realize their heterostructured cathode materials.

Here, we report a facile approach to realize surface modification of the OLO cathode materials with heterostructures; our approach only includes gas change for conventional synthesis without additional surface modification steps. We obtained Li1.167Ni0.18Mn0.548Co0.105O2, layered Li-rich oxide cathode material with enhanced electrochemical performance by reductive treatment with Ar gas.

Figure 1
Unraveling the Lithium Hydroxide Formation Reaction Mechanism in Lithium-O2 Batteries: A Theoretical Study
Authors: Torres Ana Elizabeth , Balbuena Perla B
Published: February 2020

It is important to identify the electronic factors that might enhance or hinder the formation of discharge/charge products or parasitic species within the complex electrolytic media of a lithium air battery. Although some reaction mechanisms have been proposed, the underlying reaction process by which LiOH formation occurs in the presence of LiI and water is not well understood. Similarly, the chemical decomposition reaction of LiOH, which leads toward molecular oxygen evolution still remains unknown. Herein is presented a theoretical study of the chemical reactions that may take place in the electrolytic media of a Li/O2 battery with dimethoxyethane (DME) solvent in the presence of water and the additive LiI. The results show that water is the most energetically accessible source of protons to obtain LiOH. The catalytic effect of iodide in the O-O peroxide bond scission could be ascribed to a halogen-bond interaction between the iodine atom and an oxygen nucleophilic site. The reaction pathway involving hydrogen peroxide was found to be a viable route accounting for the lithium hydroxide decomposition. Finally, the results for Li2O2 reactive species and a (Li2O2)4 cluster model were both compared.
Multi-Redox Molecule for High-Energy Redox Flow Batteries
Authors: Kwon Giyun , Lee Sechan , Hwang Jinyeon , Shim Hyun-Soo , Lee Buyngju , Lee Myeong Hwan , Ko Youngmin , Jung Sung-Kyun , Ku Kyojin , Hong Jihyun , Kang Kisuk
Published: February 2020

RFBs, which use soluble redox species dissolved in electrolytes, show great promise for large-scale energy storage systems (ESSs) because of their scalability, cost-effectiveness, and design flexibility that can decouple power and energy for diverse purposes; however, their low energy density has limited their widespread application. Most conventional ways to increase the energy density to date have relied on either exploiting high-concentration electrolytes that contain large amounts of redox materials per volume or developing redox materials with higher solubility. Although this approach of exploiting high-concentration electrolytes is simple and effective, it results in unfavorable trade-offs, including increased electrolyte viscosity and high cell resistance, and often leads to the precipitation of salts, which causes the failure of the system. Furthermore, non-aqueous RFBs can be more vulnerable to these trade-offs because of the intrinsically lower ionic conductivity of non-aqueous electrolytes compared with that of their aqueous counterparts, which typically results in inferior power capability of the system. Here, we demonstrate that the use of multi-electron molecules as redox materials can offer an alternative route to overcome these issues and achieve high-energy-density RFBs. Unlike doubling the electrolyte concentration, for instance, which would easily result in the solubility limit being exceeded or significant reduction of the kinetics, the utilization of the double-redox activity from a single-redox material would approximately double the energy density without negatively affecting the electrolyte properties. Nevertheless, the use of a second-electron redox reaction in most redox-active materials in RFBs has often been shown to be irreversible or to promote severe degradation because of the poor chemical stability of the redox materials at highly oxidized states in the solution.

In this study, we demonstrate, for the first time, an all organic flow system using a multi-electron redox-active organic material with the superior chemical stability, which is a phenazine derivative. In addition, an analysis of the electrochemical kinetic properties of redox couple on both diffusion- and charge transfer-controlled kinetic is conducted through rotating disk electrode test; The redox couple displays outstanding kinetic characteristics. Moreover, the redox couple presents the highest theoretical and practical energy density among reported redox couples for both aqueous and non-aqueous RFB at the same concentration. The redox mechanism and the chemical stability of redox couple are investigated through raman spectroscopy and density functional theory calculations. These findings on this multi-electron redox material provide a potential new pathway for the design of high-energy-density RFBs and practically feasible ESSs.
Development of High Capacity Metal-Ligand Electrolytes for Grid-Scale Non-Aqueous Redox Flow Battery
Authors: Maurya Sandip , Chu Terry , Park Eun Joo , Kim Yu Seung , Smythe Nathan , Gordon John , Davis Benjamin L , Mukundan Rangachary
Published: February 2020

Redox flow batteries (RFBs) are emerging as the preferred choice for Mega-watt scale energy storage for the future grids in large part to the decoupled energy/power outputs from the storage system [1]. However, narrow electrochemical stability window of water limits the operating voltage of aqueous flow batteries to < 1.6 V and poses an obstacle to achieving high capacity aqueous RFBs. A higher capacity (energy density) can be obtained if water is replaced with organic solvents such as acetonitrile processing a broader electrochemical stability window (>5 V). While organic solvents increase the cost per kilowatt-hour of the electrolyte this can be offset by the greater energy storage capacity of the RFBs [2]. This tradeoff can be beneficial if less-expensive metal-ligand redox couples are used in non-aqueous RFBs, especially those based on Fe on both the anolyte and catholyte [3]. The other significant cost factor of RFBs is expensive perfluorinated Nafion® membranes. Therefore, the combination of less-expensive redox couples and hydrocarbon membranes could lead to the DOE long term target of 100 USD per kWh for RFBs.

To achieve these strict economic targets, we have combined the expertise of inorganic synthesis and fuel cell capabilities at the Los Alamos National Laboratory’s towards non-aqueous flow battery development. We are systematically studying the structure-property relationship of Iron and Nickel-containing inorganic redox-active couples as anolyte and catholyte in RFBs. Design aspects of these redox couples and electrochemical characterization will be discussed in this presentation. Besides, results will be presented on specifically tailored anion exchange membrane with high compatibility with organic solvents and the active redox couples. In addition to the component work, results of flow battery testing using these novel membranes and electrolytes will be presented. A voltage window >3 V has been achieved in preliminary results using the Ni and Fe systems. The reversibility of these redox couples and their potential for long-term operation in RFBs will be discussed.

Acknowledgement

This work is supported by Laboratory Directed Research & Development, Los Alamos National Laboratory.

References:

[1] S.H. Shin, S.H. Yun, S.H. Moon, RSC Advances, 3 (2013) 9095-9116.

[2] R.M. Darling, K.G. Gallagher, J.A. Kowalski, S. Ha, F.R. Brushett, Energy & Environmental Science, 7 (2014) 3459-3477.

[3] J. Friedl, M.A. Lebedeva, K. Porfyrakis, U. Stimming, T.W. Chamberlain, Journal of the American Chemical Society, 140 (2018) 401-405.
Design of Stoichiometric Layered Potassium Transition Metal Oxide for K-Ion Batteries
Authors: Kim Haegyeom , Seo Dong-Hwa , Urban Alexander , Lee Jinhyuk , Kwon Deok-Hwang , Bo Shou-Hang , Shi Tan , Papp Joseph K , McCloskey Bryan D. , Ceder Gerbrand
Published: February 2020

The layered transition metal oxides (TMOs) which have been investigated as cathode materials for K-ion batteries (KIBs) have so far exhibited moderate specific capacity and rate capability. [1-6] However, all the layered K-TMOs reported to date are K-deficient phases (x ≤ 0.7 in K
x
TMO2),[1-6] which limits their use in practical rocking-chair batteries because a pre-potassiation process of the electrodes would be required to insert enough K in the cells. In this respect, it is important to understand the factors that destabilize (or stabilize) the layered structure of K
x
TMO2 (x = 1) and then design a stoichiometric K
x
TMO2 (x = 1) cathode material.

In this work, we find that the strong electrostatic repulsion between K ions due to the short K+-K+ distance destabilizes the layered structure in a stoichiometric composition of KTMO2. However, a stoichiometric KCrO2 is thermodynamically stable in the layered structure despite short K+-K+ distance unlike other KTMO2 compounds that form non-layered structures. The unique stability of layered KCrO2 is attributable to the unusual ligand field preference of Cr3+ in octahedral sites that can compensate for the energy penalty from the short K+-K+ distance. Therefore, we develop the stoichiometric layered KCrO2 cathode material for KIBs and investigate its K-storage properties. In K-half cells, the KCrO2 cathode delivers a reversible specific capacity of ~90 mAh/g with an average voltage of ~2.73 V (vs. K/K+). In-situ diffraction and electrochemical characterization further demonstrate multiple phase transitions via reversible topotatic reactions occurring as the K content changes.

References

Vaalma, C., et al. Non-aqueous K-ion battery based on layered K0.3MnO2 and hard carbon/carbon black. J. Electrochem. Soc. 163, A1295 (2016)

Kim, H. et al. K-ion batteries based on a P2-type K0.6CoO2 cathode. Adv. Energy Mater. 7, 1700098 (2017)

Hironaka Y. et al. P2- and P3-KxCoO2 as an electrochemical potassium intercalation host. Chem. Commun. 53, 3693 (2017)

Kim, H. et al. Investigation of potassium storage in layered P3-type K0.5MnO2 cathode. Adv. Mater. 29, 1702480 (2017)

Wang, X. et al. Earth Abundant Fe/Mn-based layered oxide interconnected nanowires for advanced K-ion full batteries. Nano Lett. 17, 544 (2017)

Liu, C. et al. K0.67Ni0.17C0.17Mn0.66O2: A cathode material for potassium-ion battery. Electrochem. Commun. 82, 150 (2017)
Fe1-Xs@N-Doped Carbon Yolk-Shell As a High Performance Anode Material for Sodium-Ion Battery
Authors: Veerasubramani Ganesh Kumar , Yuvaraj Subramanian , Park Myung-Soo , Kim Dong-Won
Published: February 2020

Lithium-ion batteries (LIBs) have intensely pervaded our daily life activities and evolved into the rampant power sources since its first launch in 1991 for various applications such as mobile phones, portable laptops, electric vehicles and energy storage systems due to their high energy density and excellent cycling stability.1 Nevertheless, by considering the drawbacks of LIBs such as limited lithium resource over the earth’s crust and the presence of uneven distribution of Li deposites and thereby increasing cost will be the primary problem for the development of advanced energy storage system in the future. Sodium-ion batteries (SIBs) have attracted great attention due to the fact that Na+ ions have similar electrochemical properties with the Li+ ions, thus the available design of LIBs could have been promptly relocated to and hasten the research on SIBs. SIBs face the challenges in development of suitable anodes due to the large volume change during sodiation/de-sodiation resulting in inferior cycling stability. Being ecofriendly and copious, pyrrhotite (Fe1-xS), has been considered as a potential anode material for SIBs.2 However, the rapid capacity loss originated by the substantial volume expansion during electrochemical reaction hinders its practical applications. In this work, we present the design and synthesis of Fe1-xS@N-doped carbon yolk-shell architecture as a promising anode material for SIBs. The optimized core-void-shell architecture exhibits the excellent capacity retention and high rate capability when compared to pristine pyrrhotite. The large electrode/electrolyte contact area and the short diffusion path for electrons and sodium ions which facilitated by the yolk-shell configuration lead to the enhanced sodium reaction rate and also mitigates the structural degradation.

References

G. Yang, J.L. Zhang, M.C.W. Kinter-Meyer, C.X. Lu, D.W. Choi, J.P. Lemmon and J. Liu, Chem. Rev.,
111, 3577 (2011).

X. Wang, J. Yang, S.L. Chou, H.K. Liu, W.X. Zhang, D. Zhao and S.X. Dou, Nat. Commun., 6, 8689 (2015).
(Invited) Transmittance Limits and Their Effects on Light Extraction from Luminescent Materials
Authors: Piquette Alan , Mishra Kailash C. , Lenef Alan
Published: February 2020

Light extraction from light emitting diodes and/or phosphors has been an increasingly studied topic over the last twenty plus years (see Figure 1). More recently, it has been shown that there is an absolute limit to the amount of electromagnetic radiation that can transmit from one medium to another across an interface defined by differing refractive indices.[1-4] This limit has been established using both thermodynamic arguments[1-3] and classical electromagnetic theory.[4] In this talk, we will briefly derive the limits of transmittance of light through an interface and discuss what implications there are for the overall extraction efficiency of a simple system.

Finite-difference time-domain (FDTD) simulations were performed to verify the transmittance limit. The results of the simulations will be presented for several different interface types, such as smooth, pseudo-random roughness, photonic crystal lattices, micro-sphere arrays, etc. It was found that regardless of the interface type, all of the simulations confirm the transmittance limit.

Finally, we will show that despite the relatively low transmittance limits, extraction efficiencies of 100% are theoretically possible, but only because of scattering and cavity effects, not through an increase of the so-called first-pass transmittance. We use a simple two-interface system and numerical simulations based on geometrical optics to demonstrate the effects of transmittance and other important factors on the overall forward extraction efficiency.

[1] J. Muschaweck and C. Wiesmann, Adv. Opt. Technol., 2, 291 (2013).

[2] A. Lenef, J. F. Kelso, and A. Piquette, Opt. Lett., 39, 3058 (2014).

[3] A. Lenef, A. Piquette, and J. Kelso, ECS J. Solid State Sci. Technol., 7, R3211 (2018).

[4] K. C. Mishra and A. Piquette, ECS J. Solid State Sci. Technol., 7, R3016 (2018).

Figure 1
Mechanistic Aspects on the Grafting By the Self-Decomposition of Aryldiazonium Salts: Effect of the Counterion
Authors: Morales-Martínez Daniel , Ramírez Vanessa , González Felipe J.
Published: February 2020

The dipping of an electrode in a solution of aryldiazonium salts is an interesting reaction to form covalently grafted films on carbon and metallic surfaces [1]. However, although there are many evidences about the existence of the grafted film, the mechanism is unknown. In 1957, it was demonstrated that p-nitrofluorobenzene was got during the thermal decomposition of p-nitrophenyldiazonium tetrafluoroborate, putting in evidence the importance of the counterion during the decomposition of the aryldiazonium cation [2]. One way to explain the formation of this specie considers the decomposition of the aryldiazonium cation by a redox reaction that involves the transient passage by radicals as intermediates, which will be responsible of the spontaneous grafting of different electrode surfaces. Hence, the theoretical and experimental study for determine the mechanism of the spontaneous grafting is performed in this work. The results showed that there is an effect of the counterion in the rate of decomposition of the aryldiazonium salt. When the counterion is easier to be oxidized, the rate of decomposition is higher, which support the idea of a mechanism with a redox reaction involved and therefore, the existence of radicals as intermediates.

References

[1] Adenier, B. Barré, E. Cabet-Deliry, A. Chaussé, S. Griveau, F. Mercier, J. Pinson, C. Vautrin-Ul, Surface Science, 2006, 600, 4801-4812.

[2] G.B. Bachman, T. Hokama, J. Am. Chem. Soc. 1957, 79, 4370-4373.