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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Quantifying the Correlation between Coordination Chemistry, Interfacial Formation, and Electrochemical Performances for Mg Battery Electrolytes

Here, the rise of magnesium batteries as promising post-Li-ion energy storage technologies has sparked considerable attention toward understanding the fundamental aspects of coordination chemistry concerning Mg cations in multivalent electrolytes. This exploration includes investigating how coordination influences crucial electrolyte properties like solubility, electroreduction stability, and the formation of the interphase, all of which are pivotal for practical battery applications. Despite recent progress in developing a few functional electrolytes, a comprehensive understanding of the solvation structure that can facilitate efficient Mg deposition performance and the formulation of general design rules based on the solvation structure is still lacking. In our study, we endeavor to establish a connection between solvent and anion interactions with Mg 2+ , interface formation, and cycling performance through a series of organic ether solvents (tetrahydrofuran, glyme, diglyme, and triglyme) and amine solvents (dimethylamine, 3-methoxypropylamine, and dimethoxyethylamine). Our findings reveal a distinct coordination trend for solvent/Mg 2+ and (Mg-TFSI):solvent across various solvents, which dictates the extent of ion pairing for TFSI salts with increasing solvent molecule size and denticity. The solvated species in the bulk electrolyte across different solvents lead to diverse interfacial chemistries with varying decomposition components. We also explore the cycling efficiency as well as Mg deposition overpotentials for different solvents. A correlation analysis was conducted to assess the interplay between the structure and performance. Lastly, we apply the insights gained from these results to tailor the relative anion/Mg 2+ coordination structures using cosolvent systems, aiming for improved cell performance.

25 ENERGY STORAGE↗
DOE OSTI2023

Morphology Evolution in Self-Healing Liquid-Gallium-Based Mg-Ion Battery Anode

Conventional solid battery anodes suffer from dendrite growth and volume changes, resulting in poor cycling performances. Self-healing electrodes made of liquid metals and alloys can overcome these issues by reversibly undergoing liquid–solid phase transformations during (dis)charging. Just recently, we achieved 1000 cycles in Mg-ion battery anodes using liquid Ga as the active material, which reversibly transformed into solid Mg 2 Ga 5 during (de)magnesiation. However, the fundamental mechanism behind this liquid–solid phase transformation remains unclear. In this follow-up work, cryogenic focused ion beam electron microscopy is used to elucidate the morphology evolution when liquid Ga embedded in a carbon-binder matrix transforms into solid Mg 2 Ga 5 during cycling. We found that liquid Ga gradually diffuses into the surrounding matrix, increasing the contact area between active material and electrolyte, facilitating the charge transfer process. These new insights will help understand the performance of alkali- and alkaline-earth-metal batteries based on liquid anodes.

25 ENERGY STORAGE↗
DOE OSTI2022

Delineating the Roles of Mn, Al, and Co by Comparing Three Layered Oxide Cathodes with the Same Nickel Content of 70% for Lithium-Ion Batteries

High-nickel layered oxides continue to prevail in the energy storage market as the frontmost cathode candidates for next-generation lithium-ion batteries. Demand and development of LiNi 1–x–y Mn x Co y O 2 (NMC) and LiNi 1–x–y Co x Al y O 2 (NCA) cathodes are rampantly increasing, particularly for the electric vehicle (EV) industry. However, the continued presence of cobalt in NMC and NCA cathodes raises global concerns due to geopolitical and ethical issues attributed to Co sourcing. We herein introduce a novel cobalt-free, high-nickel cathode LiNi 0.7 Mn 0.25 Al 0.05 O 2 (NMA70) and benchmark it against Co-containing LiNi 0.7 Mn 0.15 Co 0.15 O 2 (NMC70) as well as Co- and Al-free LiNi 0.7 Mn 0.3 O 2 (NM70) cathodes with equivalent 70% Ni contents that are all synthesized in-house. NMA70 displays a high initial C/10 capacity of 210 mA h g –1 , matching that of NMC70 in half cells with a cutoff voltage of 4.5 V. NMA70 also exhibits an impressive high-voltage full cell cycling performance with a cutoff voltage of 4.4 V with a nearly identical capacity retention of 83% compared to that of 82% for NMC70 after 300 cycles. Postmortem X-ray photoelectron spectroscopy (XPS), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and electron energy loss spectroscopy (EELS) analyses indicate a thinner cathode–electrolyte interface (CEI) developed in NMA70 compared to that in NM70 and unveil a more robust solid-electrolyte interface (SEI) passivation on the graphite anode among all samples. The benefits of Al doping are additionally highlighted with enhanced high-voltage CEI and thermal stabilities in NMA70. Furthermore, this work assesses the roles of Mn, Al, and Co to demonstrate both the practicality and feasibility of synthesizing cobalt-free, high-nickel cathodes that are promising alternatives to current NMC- and NCA-based cathodes.

25 ENERGY STORAGE↗
DOE OSTI2014

Geothermal Power Production: Alternative Scenarios and Critical Issues

This is the last in a series of reports that completes the life cycle analyses (LCAs) of geothermal power production technologies conducted by Argonne National Laboratory. It addresses the remaining critical issues pertaining to the LCAs of geothermal electricity production: the relative contributions from plant operations and maintenance (O&M), from decommissioning (dcm), from well field exploration, and from plant operational greenhouse gas (GHG) emissions to the total life cycle performance of geothermal power plants. Contributions from O&M and dcm to the performance of other power generating technologies are also discussed. Also included in this study are LCA results for a new series of scenarios for geothermal power production. Our analysis uses fossil fuel energy consumption and GHG emissions per unit of lifetime electricity output (referred to as the fossil energy and GHG ratios, respectively) as the life cycle metrics for quantifying life cycle stage contributions to their corresponding totals, which were subsequently used for comparing the environmental performance of geothermal and other electric power production plants. Based on literature results, we concluded that the contribution from dcm to both ratios is negligible for power plants in general. Further, we found that the contribution from O&M to both ratios is generally significant for facilities with no fuel cycle (fuel production and use) burdens. In the case of geothermal power production, O&M contributes about 20% to the total for enhanced geothermal power plants, 10% for geothermal binary plants, and about 25% of the energy ratio for geothermal flash and dry steam plants. However, due to operational GHG emissions that are unique among geothermal power plants, O&M contributes only about 1% of total GHG ratios for flash and dry steam plants. These GHG emissions arise when the geofluids of these plants become exposed to the atmosphere, thus releasing dissolved GHGs. The amount of GHG emissions from these plants had a wide range. However, we found that 85% of California’s running capacity in flash and dry steam plants released 160 grams or less per kilowatt-hour of electricity produced. We developed an exploration model to account for core hole, slim hole, and confirmation well drilling that includes a probability of success for confirmation well drilling. The model shows that well field exploration represents about 20% of the total life cycle burden for large geothermal plants with numerous wells and 32% of the burden for small plants with few wells. We also analyzed a set of geothermal scenario pairs. The objective was to identify geothermal scenarios with a lower levelized cost of electricity and lower life cycle burdens. A comparison of reference with improved cases within each pair revealed that the improved cases demonstrated a lower levelized cost of electricity and lower fossil energy consumption and GHG metrics. The scenario pairs covered a range of plant capacities, well numbers and depths, resource temperatures, and plant lifetimes. Finally, we found that compared to fossil-fuel generation of electricity, both flash and dry steam geothermal electricity generation result in fewer GHG emissions: on average, only one-fifth of the GHG emissions per kilowatt-hour from a natural gas combined-cycle plant, and one-tenth of those from a coal-fired plant. Moreover, these fractions were much smaller when the fossil plants were compared with plants that use geothermal binary technology.

Sullivan, J. L.↗
NASA NTRS1985

Experimental test program for evaluation of solid lubricant coating as applied to compliant foil gas bearings to 315 deg C

An experimental apparatus and test procedure was developed to compare the performance of two solid lubricant coatings for air lubricated compliant foil gas bearings in the temperature range of 25 to 315 C. Polyimide bonded additive (SBGC) were tested extensively for durability and frictional characteristics. A partial arc bearing constructed of Inconel X-750 was coated on the bore with one of these coatings. The foil was subjected to repeated start/stop cycles. Performance comparisons reveal that although both coatings survive thousands of start/stop cycles, only the PBGF coated bearing achieves the specified 9000 start/stops. There is enough wear on the SBGC coated bearing to warrant termination of the test prior to 9000 start/stop cycles due to coating failure. The frictional characteristics of the PBGF are better at the elevated temperatures than at lower temperatures; a marked increase in sliding friction occurs as the temperature decreases. The SBGC maintains relatively constant frictional characteristics independent of operating temperature.

Wagner, R. C.↗
DOE OSTI2025

Investigation of MgO additives on microstructure and properties of thin LLZO electrolytes for all-solid-state batteries

To realize high-energy density lithium lanthanum zirconate (LLZO)-based solid-state batteries (SSB), LLZO electrolytes should be fabricated with low thickness and high mechanical strength. An effective strategy for strengthening ceramic materials is to use additives. Here, we employed MgO nanopowders and fibers as additives for the thin LLZO electrolyte in order to improve the mechanical strength. The microstructure, mechanical properties, and electrochemical properties are characterized to investigate the effects of adding MgO and sintering time. The MgO remains at grain boundaries after sintering, making the microstructure of LLZO fine and uniform. The mechanical strength of the MgO-added LLZO was enhanced by more than 60% while maintaining high ionic conductivity (1 × 10 -4 S cm -1 ) at room temperature. Li symmetric cells using the MgO fiber–LLZO and MgO powder–LLZO exhibit 2 and 3 times higher critical current density (CCD) than those of pure LLZO, and a solid-state full cell exhibits stable cycling performance. Further, these results demonstrate that the use of MgO nanopowder or fiber as an additive for thin LLZO is beneficial for high-current density cycling, by improving mechanical properties and microstructure.

25 ENERGY STORAGE↗
DOE OSTI2022

Understanding Solid-Electrolyte Interphase Formation at the Lithium Metal Anode of Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are one of the most promising chemistries for the next generation of energy storage devices. In a standard Li-S cell, the metallic lithium anode is an essential component of the battery due to its low density, extremely high theoretical specific capacity, and very low negative electrochemical potential. However, several challenges related to the use of Li metal have prevented this battery technology from becoming commercially available. For instance, Li-anodes are highly reactive, which results in the continuous decomposition of the electrolyte and the formation of the solid-electrolyte interphase (SEI) layer. This, combined with the non-uniform deposition of Liions during plating at the anode surface, can seriously affect the performance, cycling, and safety of the battery. In addition, it has been suggested that a controlled SEI formation at the metallic Li anode can yield enhanced battery performance. Hence, a comprehensive understanding of how the SEI layer is formed can help elucidate improvements in this battery technology. In this work, the formation of the SEI layer in Li-S batteries is investigated using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. The stability of liquid organic-based electrolyte components, salt concentration, electron-rich environments, and the use of inorganic solid-state electrolyte (SSE) materials are explored in order to provide molecular-level fundamental insights into how the nature and composition of the electrolyte can alter the initial stages of the SEI formation. The products of electrolyte decomposition and electro-/chemical reaction pathways of liquid electrolyte component such as solvent and salts are predicted from AIMD simulations of electrolyte-anode interfaces. Energetics of reactions from DFT ground-state optimizations are also presented to confirm the decomposition mechanisms. Some significant differences are then drawn regarding the use of low and high salt concentrations. Simulations under electron-rich environments show additional multielectron electrochemical reactions of solvent and salt decomposition taking place due to the excess of electrons and the presence of radical anions in the solution. Finally, the initial stages of formation, stability, and main constituents of interfaces between Li-metal and Sbased electrodes with sulfide-based SSEs are characterized in detail.

25 ENERGY STORAGE↗
DOE OSTI2025

A Cross‐Linked Flexible Metaferroelectrolyte Regulated by 2D/2D Perovskite Heterostructures for High‐Performance Compact Solid‐State Sodium Batteries

Abstract To address the issues of limited ionic conductivity and poor interface stability at room and low temperatures in solid‐state electrolytes, a robust intrinsic ferroelectrolyte or nanoferroelectrolyte strategy for engineering solid‐state flexible ferroelectric composite electrolytes utilizing strongly coupled intrinsic ion conducting 2D/2D sodium‐rich anti‐perovskite (NaRAP)/ferroelectric perovskite heterostructures is introduced. Herein, highly scalable PVDF‐based metaferroelectrolytes with Na 2.99 Ba 0.005 OCl/Ca 2 Na 2 Nb 5 O 16 − (CNNO − ) nanosheets into a ferroelectric poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) matrix, through an in situ cross‐linking and spontaneous bridging method, for compact solid‐state sodium batteries (SSBs), are reported. Benefiting from unique well‐dispersed 3D ferroelectric coupled network and the Na 2.99 Ba 0.005 OCl/CNNO − ‐induced PVDF‐HFP ferroelectric β phase, the Na + flux is regulated, thereby inhibiting Na dendrite growth at the interface. Notably, the optimized PH‐5% NC metaferroelectrolyte exhibits rapid ion transport (1.11 × 10 −4 S cm −1 at 25 °C), a wide electrochemical window (> 4.8V), superior conformal mechanical compatibility, improved flexibility, good elasticity and flame retardancy. The solid‐state Na 3 V 2 (PO 4 ) 3 /PH‐5% NC/Na batteries present a stable cycling performance (remaining 56.4 mAh g −1 after 500 cycles at 1 C) even at 0 °C, potential for cost‐effective, safe, stable and compact SSB energy storage over 600 Wh L −1 , vastly surpassing 365 Wh L −1 of the current commercial sodium‐ion liquid‐electrolyte batteries.

Chemistry↗
DOE OSTI2018

Porous carbon nanofiber derived from a waste biomass as anode material in lithium-ion batteries

In this paper the entire process chain from raw biomass to carbon nanofiber (CNF) to high functioning lithium ion batteries (LIB) have been followed to evaluate the use of renewable materials for components of energy storage device. Electrospun CNF was prepared from a waste walnut shells using a relatively simple procedure for liquefying, electrospinning and carbonizing the fibrils. Mats of these CNF were used in LIB without binder, and the performance was measured as a function of the parameters used to prepare the nanofibers. Electrospinning solutions to polyvinyl alcohol at mass ratio of 80/20, 70/30 to 60/40 and carbonization temperature in the range from 800, 1000 to 1200 degrees C were used and the morphology, structure properties, and specific surface area of the walnut shell-derived carbon nanofiber (CNF) were comprehensively characterized. Their electrochemical performance were also investigated as electrode materials in LIB. The electrode obtained at 800 degrees C with mass ratio of 80/20 shows the highest specific capacity of 380 mA h g -1 at 0.03 A g -1 with an initial efficiency of 55.89%, and presents excellent cycling performance and high degree of reversibility (above 280 mA h g -1 specific capacity after 200 cycles at 0.1 A g -1 ).

25 ENERGY STORAGE↗
DOE OSTI2025

Dimolybdenum Paddlewheel Complexes with Cation Binding Sites as Electrolyte Additives to Manipulate the Solid-Electrolyte Interphase at Lithium Metal Anodes

The use of electrolyte additives at millimolar loadings to control the surface chemistry of lithium metal anodes (LMAs) is a leading strategy to improve lithium metal batteries and promote electrosynthetic reactions. Whereas previous studies employed either inorganic or organic additives, in this study, we report the first organometallic additive, Mo 2 (mea) 4 [1, mea = 2-(2-methoxyethoxy)acetate], a dimolybdenum paddlewheel complex that is stable under Li plating conditions and features cation binding sites in the second coordination sphere that promote reversible Li + coordination. Binding of Li + ions to 1 induces immobilization of cationically charged aggregates (or products thereof) into the solid electrolyte interphase (SEI), imparting multiple beneficial functions. The modified SEI was found to protect the LMA against parasitic side reactions, produce modest but measurable improvements to Li plating properties (e.g., overpotential, surface structure, and Coulombic efficiency), and improve interfacial charge transport properties. Furthermore, the most notable benefit to battery cycling performance appears in calendar aging tests, which show that the presence of the additive protects the LMA from parasitic side reactions that would otherwise decrease overall cell cycling efficiency over time. Collectively, these data disclose a tactic for designing electrolyte additives using principles of organometallic synthesis.

Additives↗
DOE OSTI2016

High Temperature Carbonized Grass as a High Performance Sodium Ion Battery Anode

Hard carbon is currently considered the most promising anode candidate for room temperature sodium ion batteries because of its relatively high capacity, low cost, and good scalability. In this work, switchgrass as a biomass example was carbonized under an ultrahigh temperature, 2050 °C, induced by Joule heating to create hard carbon anodes for sodium ion batteries. Switchgrass derived carbon materials intrinsically inherit its three-dimensional porous hierarchical architecture, with an average interlayer spacing of 0.376 nm. The larger interlayer spacing than that of graphite allows for the significant Na ion storage performance. Compared to the sample carbonized under 1000 °C, switchgrass derived carbon at 2050 °C induced an improved initial Coulombic efficiency. Additionally, excellent rate capability and superior cycling performance are demonstrated for the switchgrass derived carbon due to the unique high temperature treatment.

25 ENERGY STORAGE↗
DOE OSTI2020

Standard Characterization Techniques for Inorganic Phase Change Materials

Salt hydrates are promising candidates for phase change materials (PCMs) because of their low cost and high energy storage capacity. However, practical applications of salt hydrate based PCMs are limited due to their poor thermal cycling performance caused by phase separation and supercooling. Various techniques, including differential scanning calorimetry (DSC) and transient plane source (TPS) have been used to characterize salt hydrate based PCMs but may not provide full understanding of the degradation mechanism. In this manuscript, salt hydrate and graphite composites are prepared. Temperature history (T-History) method and X-ray diffraction (XRD) are utilized for measuring melting temperature, energy storage, and latent heat degradation of the PCM composites. Highlighting the importance of each technique and how each technique plays an important role in analyzing salt hydrates performance accurately. Temperature history, and X-ray diffraction are also used in conjunction to precisely predict the cause of degradation in salt hydrate PCMs with thermal cycling, as in most literatures the cause of degradation in salt hydrate are attributed to phase segregation, supercooling, and change in stichometry water concentration without any scientific validation.

Kumar, Navin↗
DOE OSTI2016

Nonlinear Conductivities and Electrochemical Performances of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Electrodes

There is increasing research attention on optimizing the carbon black nanoparticles’ structure and loading procedure for improving conductivities and thus, electrochemical performances of cathodes in lithium-ion batteries. Recently, LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) has been actively investigated due to its larger specific capacity and lower cost compared to conventional cathode materials. Presented here is a high energy density NCM523 cathode obtained by reducing the carbon content using the state-of-the-art carbon nanoparticles developed at Cabot Corporation. It is the first time that the nonlinear conductivity of NCM523 electrodes has been discovered, which is significantly impacted by the dispersion and surface crystalline quality of carbon black nanoparticles, especially when the loading of carbon black is only 1 wt%. The nonlinear conductivity of the cathodes can dramatically affect their electrochemical performances at high rates ($\geqq$3C), which is close to the tunneling saturated current. In addition, there is no discernable difference in terms of the rate and cycle performance of the NCM523 electrodes, when reducing the loading of novel carbon black nanoparticles from 5 wt% to 1 wt% in the cathode. Therefore, the energy density of the electrode can be increased by 9% by using existing commercially available electrode materials.

25 ENERGY STORAGE↗
DOE OSTI2020

Efficient Construction of a C 60 Interlayer for Mechanically Robust, Dendrite-free, and Ultrastable Solid-State Batteries

Interfacial instability between solid electrolytes (SEs) and lithium metal remains a daunting challenge for solid-sate batteries. Here, a conformal C 60 interlayer is efficiently constructed on Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) SEs by physical vapor deposition, and an ideal interfacial contact is achieved via forming an ionically conducting matrix of LixC60 with lithium metal. The obtained Li x C 60 is beneficial to hinder the growth of lithium dendrites at interface and release the local stress during the lithiation and delithiation. As a result, the Li/LAGP-C 60 /Li symmetric cells demonstrate ultra-stable cycling performance for more than 4,500 h at a current density of 0.034 mA cm -2 . The Li/LAGP-C 60 /LiFePO 4 full cells deliver a reversible capacity of 152.4 mAh g -1 at room temperature, and the capacity retention rate is 85% after more than 100 cycles. This work provides a feasible and scalable strategy to improve the SEs/Li interface for high-performance solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2013

Coordination Chemistry in magnesium battery electrolytes: how ligands affect their performance

Magnesium battery is potentially a safe, cost-effective, and high energy density technology for large scale energy storage. However, the development of magnesium battery has been hindered by the limited performance and the lack of fundamental understandings of electrolytes. Here, we present a coordination chemistry study of Mg(BH 4 ) 2 in ethereal solvents. The O donor denticity, i.e. ligand strength of the ethereal solvents which act as ligands to form solvated Mg complexes, plays a significant role in enhancing coulombic efficiency of the corresponding solvated Mg complex electrolytes. A new and safer electrolyte is developed based on Mg(BH4)2, diglyme and optimized LiBH4 additive. The new electrolyte demonstrates 100% coulombic efficiency, no dendrite formation, and stable cycling performance with the cathode capacity retention of ~90% for 300 cycles in a prototype magnesium battery.

25 ENERGY STORAGE↗
DOE OSTI2021

Building a spontaneously formed and self-healing protective layer with an F-rich electrochemically active organic molecule for ultra-stable Li metal batteries

Additives in the electrolyte act as engineers in Li metal batteries. Inspired by the superior cycle performance of organic materials in half cells, tetrafluoro-1,4-benzoquinone (TFBQ), the main structure of which has been widely applied as an organic cathode material, is utilized for the first time as an additive for Li metal protection. By chemical and electrochemical reactions between TFBQ and the Li metal surface, an F-rich interface layer is in situ formed on the Li metal surface during the charge and discharge process. From electrochemical tests and characterization, the powerful self-healing ability of the interface layer enabled by TFBQ is revealed, making an extremely stable Li metal anode. By using a lean electrolyte with 0.1 M TFBQ, the cycle life of Li|Li symmetric cells is increased at least 6 times compared to the control group. Moreover, impressive full cell performance was achieved. Ultra-stable Li–LFP cells showed a 0.026% average degradation for 600 cycles at 1C and Li–NMC622 cells showed a 36.8% higher capacity compared to the control group over 200 cycles at 0.5C, which are among the best results reported. Furthermore, this work efficiently and conveniently provides a new research direction to Li metal protection and Li metal batteries.

25 ENERGY STORAGE↗