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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3

Toward high solids loading process for lignocellulosic biofuel production at a low cost: Biofuel Production at High Solids Loading

High solids loadings (>18 wt%) in enzymatic hydrolysis and fermentation are desired for lignocellulosic biofuel production at a high titer and low cost. However, sugar conversion and ethanol yield decrease with increasing solids loading. The factor(s) limiting sugar conversion at high solids loading is not clearly understood. In the present study, we investigated the effect of solids loading on simultaneous saccharification and co-fermentation (SSCF) of AFEX™ (ammonia fiber expansion) pretreated corn stover for ethanol production using a xylose fermenting strain Saccharomyces cerevisiae 424A(LNH-ST). Decreased sugar conversion and ethanol yield with increasing solids loading were also observed. End-product (ethanol) was proven to be the major cause of this issue and increased degradation products with increasing solids loading was also a cause. For the first time, we show that with in situ removal of end-product by performing SSCF aerobically, sugar conversion stopped decreasing with increasing solids loading and monomeric sugar conversion reached as high as 93% at a high solids loading of 24.9 wt%. In this work, techno-economic analysis was employed to explore the economic possibilities of cellulosic ethanol production at high solids loadings. The results suggest that low-cost in situ removal of ethanol during SSCF would significantly improve the economics of high solids loading processes.

09 BIOMASS FUELS↗

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State 15N NMR Spectroscopy

The solid-state 15N NMR powder spectra of the thorium nitride complex, [K(18-crown-6)(THF)2][(R2N)3Th(m-15N)(Th(NR2)3] ([K][1-15N], R = SiMe3), and the thorium amide complex, [Th(NR2)3(15NH2)] (2-15N) were recorded. The spectrum for [K][1-15N] represents the first reported solid-state 15N NMR data for an actinide nitride complex. The experimentally measured tensor spans are 847 ppm for [K][1-15N] and 237 ppm for 2-15N. Both shielding tensors exhibit a near-zero asymmetry parameter, which for [K][1-15N] is consistent with a local rotational symmetry of its 15N-labelled nitride ligand. For 2-15N, the lack of asymmetry can be rationalized by a quasi-free Th-NH2 bond rotation in the solid-state. DFT calculations overestimate the tensor span somewhat for [K][1-15N], but provide isotropic shifts in good agreement with both the solid-state and solution values for both complexes. Natural localized molecular orbital (NLMO) analyses of the nuclear shielding reveal that the larger tensor span in [K][1-15N] vs. 2-15N is primarily a consequence of more pronounced covalency of the N-Th bonds, and large spin-orbit coupling due to significant Th 5f orbital contribution to those bonds, impacting the principal components of the shielding tensor perpendicular to the Th-N-Th axis. Overall, our analysis confirms the involvement of the 5f orbitals in Th-N multiple bonds, and further demonstrates the value of solid-state NMR spectroscopy for interrogating actinide-ligand bonding.

actinides, covalent bonding, Nuclear Magnetic Reso↗

First principles study on electrochemical and chemical stability of solid electrolyte–electrode interfaces in all-solid-state Li-ion batteries

All-solid-state Li-ion batteries based on ceramic solid electrolyte materials are a promising next-generation energy storage technology with high energy density and enhanced cycle life. The poor interfacial conductance is one of the key limitations in enabling all-solid-state Li-ion batteries. However, the origin of this poor conductance has not been understood, and there is limited knowledge about the solid electrolyte–electrode interfaces in all-solid-state Li-ion batteries. In this paper, we performed first principles calculations to evaluate the thermodynamics of the interfaces between solid electrolyte and electrode materials and to identify the chemical and electrochemical stabilities of these interfaces. Our computation results reveal that many solid electrolyte–electrode interfaces have limited chemical and electrochemical stability, and that the formation of interphase layers is thermodynamically favorable at these interfaces. These formed interphase layers with different properties significantly affect the electrochemical performance of all-solid-state Li-ion batteries. The mechanisms of applying interfacial coating layers to stabilize the interface and to reduce interfacial resistance are illustrated by our computation. This study demonstrates a computational scheme to evaluate the chemical and electrochemical stability of heterogeneous solid interfaces. Finally, the enhanced understanding of the interfacial phenomena provides the strategies of interface engineering to improve performances of all-solid-state Li-ion batteries.

25 ENERGY STORAGE↗

Solid electrolyte for solid-state batteries: Have lithium-ion batteries reached their technical limit?

With increasing demand for electrical power on a distribution grid lacking storage capabilities, utilities and project developers must stabilize what is currently still intermittent energy production. In fact, over half of utility executives say “the most important emerging energy technology” is energy storage. Advanced, low-cost battery designs are providing promising stationary storage solutions that can ensure reliable, high-quality power for customers, but research challenges and questions lefts. Have lithium-ion batteries (LIBs) reached their technical limit? The industry demands are including high costs, inadequate energy densities, long recharge times, short cycle-life times and safety must be continually addressed. Safety is still the main problem on developing the lithium ion battery.The safety issue must be considered from several aspects, since it would become serious problems, such as an explosion in a Japan Airlines 787 Dreamliner’s cargo hold, due to the battery problem. The combustion is mainly due to the leakage or shortcut of the electrodes, caused by the liquid electrolyte and polymer separator. For this reason, the research on solid electrolyte for replacing the existing liquid electrolyte is very important. The materials used in existing lithium ion battery, such as a separator and liquid electrolyte must be replaced to new solid electrolytes, solid materials that exhibits high ionic conductivity. Due to these reasons, research on solid state ionics materials have been vastly growing worldwide, with the main aim not only to search new solid electrolyte to replace the liquid one, but also looking for low cost materials and environmentally friendly. A revolutionary paradigm is also required to design new stable anode and cathode materials that provide electrochemical cells with high energy, high power, long lifetime and adequate safety at competitive manufacturing costs. Lithium superionic conductors, which can be used as solid electrolytes, promise the potential to replace organic liquid electrolytes and thereby improve the safety of next-generation high-energy batteries. Li{sub 3}PO{sub 4} has been proved to be a good candidate for solid electrolyte, due to its easy in preparation, low cost, high melting temperature and good compatibility with the electrode materials. In the present work, Li{sub 3}PO{sub 4} has been prepared by wet chemical reaction, a simple method with the advantage of recycling a waste product H{sub 3}PO{sub 4}. The crystal structure has been characterized by both neutron and x-ray diffraction. The use of neutron scattering plays important role on observing the light atoms such as lithium ion. The x-ray diffraction results showed the crystal structure of orthorhombic phase P m n 21 (31), that belongs to the β-Li{sub 3}PO{sub 4}, with the lattice parameters are a = 6.123872, b = 5.250211, c = 4.876378. The conductivity of β-Li{sub 3}PO{sub 4} was around 10{sup −8} S/cm. Furthermore, the future application of the solid electrolyte layer in lithium ion battery will also be considered. It is concluded that the used of local resources on producing the solid electrolyte Li{sub 3}PO{sub 4} for lithium ion battery will give more added values to the researches and national industry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Solid electrolytes and interfaces in all-solid-state sodium batteries: Progress and perspective

All-solid-state sodium batteries are promising candidates for the next generation of energy storage with exceptional safety, reliability and stability. The solid electrolytes are key components for enabling all-solid-state sodium batteries with high electrochemical performances. This Review discusses the current developments on inorganic and organic sodium ions solid electrolytes, including β/β’’-alumina, NASICON, sulfides, polymers and others. In particular, the structures, ionic conductivities and fabrications as well as electrochemical/chemical stabilities of solid electrolytes are discussed. Furthermore, the effective approaches for forming intimate interfaces between solid electrolytes and electrodes are also reviewed. And perspectives on future developments in the field of solid electrolytes and possible directions to improve interfacial contacts for future practical applications of all-solid-state sodium batteries are included.

25 ENERGY STORAGE↗

An Electron/Ion Dual‐Conductive Alloy Framework for High‐Rate and High‐Capacity Solid‐State Lithium‐Metal Batteries

Abstract The solid‐state Li battery is a promising energy‐storage system that is both safe and features a high energy density. A main obstacle to its application is the poor interface contact between the solid electrodes and the ceramic electrolyte. Surface treatment methods have been proposed to improve the interface of the ceramic electrolytes, but they are generally limited to low‐capacity or short‐term cycling. Herein, an electron/ion dual‐conductive solid framework is proposed by partially dealloying the Li–Mg alloy anode on a garnet‐type solid‐state electrolyte. The Li–Mg alloy framework serves as a solid electron/ion dual‐conductive Li host during cell cycling, in which the Li metal can cycle as a Li‐rich or Li‐deficient alloy anode, free from interface deterioration or volume collapse. Thus, the capacity, current density, and cycle life of the solid Li anode are improved. The cycle capability of this solid anode is demonstrated by cycling for 500 h at 1 mA cm −2 , followed by another 500 h at 2 mA cm −2 without short‐circuiting, realizing a record high cumulative capacity of 750 mA h cm −2 for garnet‐type all‐solid‐state Li batteries. This alloy framework with electron/ion dual‐conductive pathways creates the possibility to realize high‐energy solid‐state Li batteries with extended lifespans.

Yang, Chunpeng↗

Wet chemical synthesis and properties of argyrodite sulfide solid electrolytes for solid state lithium batteries

The commercialization of the lithium-ion battery (LIB) in 1991 was responsible for the explosion in portable electronic technologies that has been seen over the past 30 years. With the advent of electric vehicles and other high-powered technologies, there is tremendous demand for LIBs with higher energy density and high safety. To achieve this, new electrode materials must be explored. The obvious choice of anode material would be pure metal lithium, which has a theoretical specific capacity of 3860 mAh g-1 . Unfortunately, metal lithium anodes have not been widely commercialized due to their tendency to react violently with the flammable liquid electrolytes used in today’s batteries. Battery safety can best be achieved by adopting solid electrolytes in place of liquid electrolytes. Solid electrolytes are nonvolatile and nonflammable, safely allowing for the combination of high-capacity cathode materials with a Li metal anode. Argyrodite sulfide solid electrolytes such as halogen-doped Li6PS5X (X = Cl, Br, I) are noted for their high ionic conductivity. But before sulfides can be commercially adopted, they possess several disadvantages which must be addressed, including time- and energy-consuming synthesis processes, poor electrochemical stability, and intrinsically poor air stability. This dissertation seeks to address each of these challenges through materials design an synthesis strategies. In this work, we pioneer a solvent-based approach for the synthesis of argyrodite solid electrolytes Li7PS6 and Li6PS5Xinstead of a stringent solid-state synthesis. Nontoxic ethanol is employed as the solvent, enabling a rapid synthetic approach to produce argyrodite solid electrolytes with high phase purity and compositional flexibility. Compared with Li7PS6, halogen doping (i.e. X = F, Cl, Br, I) not only increases the ionic conductivity, but also enhances the electrochemical stability at the interface towards Li metal. Specifically, F-doped argyrodites produce a robust SEI layer containing LiF, contributing to enhanced interfacial stability. Finally, to address the air instability challenge, argyrodite-incorporated composite solid electrolytes (CSEs) are designed and prepared to produce stable and flexible membranes that are demonstrated in solid-state Li metal batteries. These advances push argyrodite sulfide solid electrolyte research further and pave the way for the proliferation of next generation lithium metal batteries.

25 ENERGY STORAGE↗

Fabrication of ultrathin solid electrolyte membranes of β-Li 3 PS 4 nanoflakes by evaporation-induced self-assembly for all-solid-state batteries

All-solid-state lithium batteries are attractive candidates for next-generation energy storage devices because of their anticipated high energy density and intrinsic safety. Owing to their excellent ionic conductivity and stability with metallic lithium anodes, nanostructured lithium thiophosphate solid electrolytes such as β-Li 3 PS 4 have found use in the fabrication of all-solid lithium batteries for large-scale energy storage systems. However, current methods for preparing air-sensitive solid electrolyte membranes of lithium thiophosphates can only generate thick membranes that compromise the battery's gravimetric/volumetric energy density and thus its rate performance. To overcome this limitation, the solid electrolyte's thickness needs to be effectively decreased to achieve ideal energy density and enhanced rate performance. In this paper, we show that the evaporation-induced self-assembly (EISA) technique produces ultrathin membranes of a lithium thiophosphate solid electrolyte with controllable thicknesses between 8 and 50 μm while maintaining the high ionic conductivity of β-Li 3 PS 4 and stability with metallic lithium anodes up to 5 V. Finally, it is clearly demonstrated that this facile EISA approach allows for the preparation of ultrathin lithium thiophosphate solid electrolyte membranes for all-solid-state batteries.

25 ENERGY STORAGE↗

ZnxMn1-xO Solid Solutions in the Rocksalt Structure: Optical, Charge Transport, and Photoelectrochemical Properties

Theoretical predictions of ZnO:MnO solid solutions (abbreviated here as ZMO) with the rocksalt-type structure suggest improved visible light absorption and suitable band edge positions for the overall water splitting reaction, but experimental efforts to produce such phases are limited by the low solubility of Zn within this structure type. Here, we produce solid solutions of ZnxMn1-xO, with x = 0.5 and 0.3 in the metastable rocksalt phase, using high-pressure and high-temperature (HPHT) techniques. X-ray diffraction and electron microscopy methods were employed to determine the crystal structure, chemical composition, and homogeneity on the submicron scale. The solid solutions exhibit increased optical absorbance in the visible spectral range as compared to those of the parent oxides ZnO and MnO. Our theoretical calculations for ZnxMn1-xO with x = 0.5, 0.25 predict band gaps of 2.53 and 2.98 eV, respectively, with an unusually large band gap bowing. Our calculations also show small effective electron mass for these materials indicating their potential for solar energy applications. Initial photoelectrochemical tests reveal that ZMO solid solutions are suitable for water oxidation and warrant further experimental optimization.

36 MATERIALS SCIENCE↗

Progress and Prospects of Inorganic Solid-State Electrolyte-Based All-Solid-State Pouch Cells

Here, all-solid-state batteries have piqued global research interest because of their unprecedented safety and high energy density. Significant advances have been made in achieving high room-temperature ionic conductivity and good air stability of solid-state electrolytes (SSEs), mitigating the challenges at the electrode–electrolyte interface, and developing feasible manufacturing processes. Along with the advances in fundamental study, all-solid-state pouch cells using inorganic SSEs have been widely demonstrated, revealing their immense potential for industrialization. This review provides an overview of inorganic all-solid-state pouch cells, focusing on ultrathin SSE membranes, sheet-type thick solid-state electrodes, and bipolar stacking. Moreover, several critical parameters directly influencing the energy density of all-solid-state Li-ion and lithium–sulfur pouch cells are outlined. Finally, perspectives on all-solid-state pouch cells are provided and specific metrics to meet certain energy density targets are specified. This review looks to facilitate the development of inorganic all-solid-state pouch cells with high energy density and excellent safety.

25 ENERGY STORAGE↗

Kinetics and Rheological Behavior of Higher Solid (Solids >20%) Enzymatic Hydrolysis Reactions Using Dilute Acid Pretreated, Deacetylation and Disk Refined, and Deacetylation and Mechanical Refined (DMR) Corn Stover Slurries

Many potential biochemical pathways producing advanced hydrocarbon fuels from renewable lignocellulosic biomass require hydrolysates with high sugar concentrations and low toxicity, enabling flexible fermentation strategies, such as fed-batch fermentations capable of producing high product titers and production rates during fermentation. High sugar concentrations also increase the osmotic pressure in the hydrolysates, thus helping to decrease contamination issues. We have shown the production of high sugar concentrations directly from biomass without the need for energy/capital intensive concentration, conditioning, and/or purification steps. In our previous work, we successfully demonstrated high biomass-derived sugar concentrations (over 230 g/L fermentable sugars) in enzymatic hydrolysis from high solid (>20 wt % insoluble solids) digestions of dilute alkali deacetylated and mechanically refined (DMR) corn stover slurries. The goal of this work was to understand the effects of initial solid loadings on differently pretreated corn stover substrates on the rheological property changes of enzymatic-hydrolyzed slurries as well as the rates and yields of the enzymatic hydrolysis reactions. We performed high-solid enzymatic hydrolysis using deacetylated and disk refined (DDR), DMR, and dilute acid pretreated (DAP) corn stover substrates at four different initial total solid loadings, 17, 22, 27, and 32%. Slurry samples were collected at regular intervals for measurements of monomeric and oligomeric sugar concentrations (glucose and xylose), particle size distributions, viscosities, and yield stresses. We produced over 270 g/L of fermentable, monomeric sugars (157 g/L of glucose and 114 g/L of xylose) at 32 wt % total insoluble solid during enzymatic hydrolysis of the DMR substrates. The pumpabilities of the digested, high-solid enzymatic hydrolysates were shown to be comparable to other commercially relevant slurry streams, such as honey, peanut butter, and ketchup from the food industry. The conversion and rheological results indicate that high-solid enzymatic hydrolysis (~33 wt %) of DMR substrates is a promising and scalable technology for producing high sugar concentration slurries from lignocellulosic biomass.

09 BIOMASS FUELS↗

A directional microcrack damage theory for brittle solids based on continuous hyperplasticity

We present a novel microcrack-damage theory for brittle solids under compression. Instead of using internal variables like zeroth, second or fourth rank damage tensors, the state of material damage is represented by an internal function that encapsulates the information of direction, density and size of microcracks. Just like other internal variables, the evolution of this state function must obey the second law of thermodynamics for arbitrary loading paths. This is done by casting the model in the framework of continuous hyperplasticity and enforcing a non-negative dissipation rate functional. The proposed framework offers predictions on the continuous evolution of microcrack density and the induced material anisotropy along with the macroscopic stress-strain curves. The use of continuous damage function grants the model significantly enhanced resolution in characterizing the direction-dependent response of cracked solids compared to classical models that are based on damage tensors. Two scenarios are considered in developing the theory, one assumes frictionless cracks and the other incorporates friction between crack surfaces. The results highlight that inelasticity, pressure dependence, and loading-unloading hysteresis exhibited by brittle solids are natural consequences of frictional microcracks. The proposed theory offers a generic and versatile framework to upscale micromechanical processes operating at individual crack scale to explain the macroscopic behavior of cracked solids.

Materials Science↗