Carbon-based artificial SEI layers for aqueous lithium-ion battery anodes
Artificial SEI layers passing lithium ions but blocking water molecules for long-lasting aqueous lithium-ion batteries.
Subramanya, Usha↗
SEARCH · Search NASA
Results for “carbon anode”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A novel battery scheme: Coupling nanostructured phosphorus anodes with lithium sulfide cathodes
Lithium-ion batteries are approaching their theoretical limit and can no longer keep up with the increasing demands of human society. Lithium-sulfur batteries, with a high theoretical specific energy, are promising candidates for next generation energy storage. However, the use of Li metal in Li-S batteries compromises both safety and performance, enabling dendrite formation and causing fast capacity degradation. Previous studies have probed alternative battery systems to replace the metallic Li in Li-S system, such as a Si/Li2S couple, with limited success in performance. Recently, there is a focus on red P as a favorable anode material to host Li. In this work, we establish a novel battery scheme by utilizing a P/C nanocomposite anode and pairing it with a Li 2 S coated carbon nanofiber cathode. We find that red P anode can be compatible in ether-based electrolyte systems and can be successfully coupled to a Li 2 S cathode. Our proof of concept full-cell displays remarkable specific capacity, rate and cycling performances. We expect our work will provide a useful alternative system and valuable insight in the quest for next generation energy storage devices.
25 ENERGY STORAGE↗
Probing the Effectiveness in Stabilizing Lithium Metal Anodes through Functional Additives
A variety of electrolyte additives were comprehensively evaluated to understand their relative capability in stabilizing lithium metal anode. Although the Li||Cu test is an effective test to rule out ineffective additives, a reliable assessment of individual additives cannot be obtained just by a single evaluation method. Therefore, various methods must be combined to truly assess the stabilization of a lithium anode. Moreover, it was also discovered that a significant depletion of electrolytes occurred during the end-of-life of the lithium batteries, which partially contributed to the sudden failure of the lithium batteries during cycling. However, the main culprit of the sudden failure was identified as the significant increase in the resistance of the lithium metal anode. Further, when used as an additive, cyclic fluorinated carbonates are the most effective in stabilizing the lithium anode and improving the cycling performance of lithium batteries among all the common additives. Despite its cost-effectiveness, the additive in the conventional electrolyte approach provides insufficient protection for lithium metal due to the complete consumption of the additive materials, which is necessary to repair the solid-electrolyte interphase (SEI). Therefore, it is suggested that a larger ratio (>15 wt %) of the SEI former should be employed to achieve effective lithium stabilization.
25 ENERGY STORAGE↗
Stabilized birnessite cathode for high power and high energy density applications
A battery comprises a housing, an electrolyte disposed in the housing, an anode disposed in the housing, a stabilized cathode disposed in the housing and comprising a cathode material. The cathode material comprises a composition selected from birnessite or layered-polymorph of manganese dioxide (δ-MnO2), the composition being stabilized by bismuth and copper ions, a conductive carbon, and a binder. The anode can be at least 50% (m/m) lithium, magnesium, aluminum, or zinc.
Yadav, Gautam G.↗
Catalytic and electrocatalytic performance of Sr(Ti 0.3 Fe 0.7 Ru 0.07 )O 3-δ for applications in solid oxide fuel cells supplied with ethanol steam reforming mixtures
We discuss how direct utilization of alcohols in Solid Oxide Fuel Cells (SOFCs) can improve the conversion efficiency by using excess heat for internal reforming and simplify the system balance of plant. Thanks to their scarce carbon- formation tendency, perovskite oxide anodes are promising alternatives to Ni-based cermets. Here we show that Sr(Ti 0.3 Fe 0.7 Ru 0.07 )O 3-δ (STF-Ru) exsolution anodes provide both catalytic reforming activity and electro- chemical activity with steam/ethanol (S/E) mixtures at 3:1 and 2:1 M ratio between 700 and 800 °C. Electrolyte- supported scandia stabilized zirconia SOFCs with STF-Ru anodes and Sr 0.95 Ti 0.3 Fe 0.7 O 3-δ (STF) cathodes are reasonably stable in the 3:1 S/E mixture over 20 h at 800 °C, with maximum power density of 195 mW/cm 2 and 140 mW/cm 2 at 0.7 V. Deactivation instead occurs with the 2:1 S/E mixture. Comparatively, cells with Ni-YSZ anodes rapidly coke and fail under the same conditions. Ethanol steam reforming experiments in a fixed bed powder reactor reveal that, above 650 °C, gas phase reactions convert ethanol to CO, hydrogen, acetaldehyde and ethylene, while STF-Ru catalyzes steam reforming. Thermogravimetric and Raman characterizations show that a moderate amount of carbon is deposited on the STF-Ru surface, which is more amorphous than the disruptive carbon which degrades Ni-YSZ.
09 BIOMASS FUELS↗
Validating corrosion models: Influence of physical properties
In chloride containing environments, two metals in physical contact can undergo galvanic corrosion limiting the lifetime of components. Being able to accurately predict galvanic corrosion damage distributions over time has not been widely presented in literature. Therefore, Finite Element Method (FEM) corrosion models were experimentally validated for two galvanic couples as a function of governing equations, environment, anode material, anode:cathode ratio, and time. Carbon steel/stainless steel (CS/SS) and zinc/stainless steel (Zn/SS) galvanic couples were exposed to NaCl solutions at room temperatures for up to 14 days. For the galvanic couples and environments, the Laplace equation with variable conductivity and reactions was sufficient to model the experimental corrosion damage. Increasing the chloride concentration for the CS/SS galvanic couple, regardless of the anode:cathode ratio, decreased the observed and modeled corrosion damage. Decreasing the anode:cathode ratio (i.e., increasing the cathode length), increased the experimentally observed and modeled corrosion damage. For small anode:cathode ratios, the governing equations deviate over long time periods with the Nernst-Plank equation being conservative. For the Zn/SS galvanic couple, the cathode length controls the dominant cathodic reduction reaction. For small cathode lengths, the hydrogen evolution reaction is dominant. For larger cathode lengths, the oxygen reduction reaction is dominant. The results are discussed with regard to the influence of solution chemistry, ohmic drop, and governing reactions. Overall, validated FEM models were presented, and the resultant models, physics, and mechanisms can be applied to other corrosion scenarios with confidence.
Carbon steel↗
Electrolytes for lithium-ion batteries operating at extreme conditions
Electrolytes for lithium ion batteries with carbon-based, silicon-based, or carbon- and silicon-based anodes include a lithium salt; a nonaqueous solvent comprising at least one of the following components: (i) an ester, (ii) a sulfur-containing solvent, (iii) a phosphorus-containing solvent, (iv) an ether, (v) a nitrile, or any combination thereof, wherein the lithium salt is soluble in the solvent; a diluent comprising a fluoroalkyl ether, a fluorinated orthoformate, a fluorinated carbonate, a fluorinated borate, a fluorinated phosphate, a fluorinated phosphite, or any combination thereof, wherein the lithium salt has a solubility in the diluent at least 10 times less than a solubility of the lithium salt in the solvent; and an additive having a different composition than the lithium salt, a different composition than the solvent, and a different composition than the diluent. In some electrolytes, the nonaqueous solvent comprises an ester.
Cao, Xia↗
Influence of surface chemistry on Li nucleation energetics on graphene-based surfaces
Lithium metal is a promising high-capacity anode material for solid-state batteries, but it typically suffers from poor cyclability. Carbon scaffold hosts have the potential to improve this performance due to their high electronic conductivity and large surface area, which facilitates lithium-ion adsorption and desorption. Scaffold surface chemistry is known to significantly influence performance outcomes, but the details of these interactions are not fully understood. Here, this study employs first-principles simulations to explore lithium transport and nucleation on graphene anodes with various surface chemistries. Using enhanced sampling techniques, ab initio molecular dynamics, and density functional theory calculations, we find that although surface chemistry has a minimal impact on lithium interfacial transport, it influences surface nucleation significantly. Both heteroatom dopants and intrinsic defects lower the nucleation barrier, creating a more favorable environment for lithium nucleation compared to pristine graphene. In addition, our results reveal a complex interplay between surface lithium concentration, lithium transport, and nucleation kinetics. These findings highlight the potential of surface modifications to precisely control nucleation processes on carbon-based anodes and provide design guidance for reducing dendrite formation and improving the cycle life of solid-state batteries.
36 MATERIALS SCIENCE↗
Growth and Performance of High-Quality SWCNT Forests on Inconel Foils as Lithium-Ion Battery Anodes
Large-scale production of vertically aligned single-walled carbon nanotubes (VA-SWCNTs) on metal foils promises to enable technological advancements in many fields, from functional composites to energy storage to thermal interfaces. In this work, we demonstrate growth of high-quality (G/D > 6, average diameters ~ 2–3 nm, densities > 10 12 cm –2 ) VA-SWCNTs on Inconel metal for use as a lithium-ion battery (LIB) anode. Scale-up of SWCNT growth on Inconel 625 to 100 cm 2 exhibits nearly invariant CNT structural properties, even when synthesis is performed near atmospheric pressure, and this robustness is attributed to a growth kinetic regime dominated by the carbon precursor diffusion in the bulk gas mixture. SWCNT forests produced on large-area metal substrates at close to atmospheric pressure possess a combination of structural features that are among the best demonstrated so far in the literature for growth on metal foils. Leveraging these achievements for energy applications, we demonstrate a VA-SWCNT LIB anode with capacity >1200 mAh/g at 1.0C and stable cycling beyond 300 cycles. Furthermore, this robust synthesis of high-quality VA-SWCNTs on metal foils presents a promising route toward mass production of high-performance CNT devices for a broad range of applications.
Energy↗
Recovery of High Value Anode Materials for a Closed Loop Li-ion Battery Recycling Process (Final Report)
Battery Resourcers’ goal with this Small Business Innovative Research Phase 1 project was to produce high quality and high purity graphite generated from its Li-ion battery recycling technology. Battery Resourcers’ technology recovers cathode material from a broad spectrum of Li-ion battery regardless of size, shape or chemistry. In Battery Resourcers existing model, the graphite is recovered to be used as a reductant and therefore the battery materials cost or recycling cost is not lowered by the recovery of the graphite. Currently, Battery Resourcers is piloting its lithium ion battery recycling process and the recovered LiNi 0.33 Mn 0.33 Co 0.33 O 2 (NMC111) or LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC111) cathode materials have shown that they can outperform existing commercial NMC111 cathode materials while being produced at a projected lower cost. Battery Resourcers and its subcontractor WPI have demonstrated the same success with the recovered graphite for anode materials. The success of this award will enable Battery Resourcers offer lowest cost anode materials while reducing the carbon footprint of the battery industry. This will potentially lower the cost of EV by lowering the upfront cost of the battery and the end of life disposal costs. The technical objectives of this Phase 1 research project are to purify the recovered graphite from Battery Resourcers leaching process and demonstrate it is viable to be used in new electric vehicle lithium ion batteries. This project demonstrated that Battery Resourcers can recover graphite with less than 2% impurities. To separate the graphite from other materials Battery Resourcers will employed new filtering techniques and chemical processing methods.
25 ENERGY STORAGE↗
New Insights into the High‐Performance Black Phosphorus Anode for Lithium‐Ion Batteries
Abstract Black phosphorus (BP) is a promising anode material in lithium‐ion batteries (LIBs) owing to its high electrical conductivity and capacity. However, the huge volume change of BP during cycling induces rapid capacity fading. In addition, the unclear electrochemical mechanism of BP hinders the development of rational designs and preparation of high‐performance BP‐based anodes. Here, a high‐performance nanostructured BP–graphite–carbon nanotubes composite (BP/G/CNTs) synthesized using ball‐milling method is reported. The BP/G/CNTs anode delivers a high initial capacity of 1375 mA h g −1 at 0.15 A g −1 and maintains 1031.7 mA h g −1 after 450 cycles. Excellent high‐rate performance is demonstrated with a capacity of 508.1 mA h g −1 after 3000 cycles at 2 A g −1 . Moreover, for the first time, direct evidence is provided experimentally to present the electrochemical mechanism of BP anodes with three‐step lithiation and delithiation using ex situ X‐ray diffraction (XRD), ex situ X‐ray absorption spectroscopy (XAS), ex situ X‐ray emission spectroscopy, operando XRD, and operando XAS, which reveal the formation of Li 3 P 7 , LiP, and Li 3 P. Furthermore, the study indicates an open‐circuit relaxation effect of the electrode with ex situ and operando XAS analyses.
Li, Minsi↗
Examining CO 2 as an Additive for Solid Electrolyte Interphase Formation on Silicon Anodes
In this study, we demonstrate that the addition of CO 2 to a standard 1.0 M LiPF 6 3:7 wt% ethylene carbonate:ethyl methyl carbonate electrolyte results in the formation of a thinner insoluble solid electrolyte interphase (SEI) that is dominated by the presence of LiF. In contrast, cells without CO 2 result in a thicker insoluble SEI layer containing more organic constituents. The CO 2 is incorporated in the dimethyl carbonate soluble part of the SEI composed primarily of polymeric poly(ethylene oxide) (PEO) on the surface of a thin inorganic layer. This combination of properties from CO 2 addition provides an improved cycling performance through the reduction of irreversible side reactions, leading to higher coulombic efficiency. The results indicate that CO 2 incorporates into the SEI and plays a role similar to additives like fluorinated ethylene carbonate and vinylene carbonate with respect to polymeric components.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Unlocking the self-supported thermal runaway of high-energy lithium-ion batteries
Layered Ni-rich LiNi x Mn y Co 1-x-y O 2 (NMC) materials are the most promising cathode materials for Li-ion batteries due to their favorable energy densities. However, the low thermal stability typically caused by detrimental oxygen release leads to significant safety concerns. Determining the pathways of oxygen evolution reaction is essential, as the ideal safety countermeasure is to break the reaction chain of thermal runaway. In this study, we demonstrate that two endogenous pathways of oxygen involved in strong exothermic reactions lead the NMC811|graphite pouch cell to an uncontrollable state, and we quantify the individual contribution of the pathways to thermal runaway. Approximately 41% of thermal-induced oxygen reacts aggressively with ethylene carbonate (EC) at the cathode/electrolyte interface with 16% heat generation, accelerating the self-heating rate and thereby further triggering thermal runaway. The residual oxygen that survives the reaction with carbonate spreads to the lithiated anode with major heat generation (65%), bringing the battery to the maximum destructive temperature during thermal runaway. By confirming the significant roles of EC and anode, a deeper understanding on battery fire was achieved. Finally, the revealed mechanism can help guide studies on stopping the two reaction pathways, allowing for the safer use of high-energy lithium-ion batteries in the future.
25 ENERGY STORAGE↗
Solid Electrolyte Interphase Formation at the Ionic Liquid Electrolyte—Lithium-Metal Interface Using an Ab Initio Molecular Dynamics Approach
An interfacial study is performed using ab initio molecular dynamics (AIMD) simulations to elucidate the electrochemical interfacial stability of an ionic liquid (IL) as component of an electrolyte in contact with a Li-metal anode when an additive, vinylene carbonate (VC), is added to the electrolyte. The IL electrolyte is composed of 1-butyl-1-methylpyrrolidinium bis(fluoro-sulfonyl)-imide (PYR14 + FSI − ) with lithium bis(trifluoromethane-sulfonyl)imide salt (Li + TFSI − ) in a 8:2 concentration ratio. Reactions observed at the interface electrolyte/Li-metal during the AIMD simulations are verified by electronic structure calculations using density functional theory calculations considering a continuum solvent model. We found that the addition of VC to the IL prevents further reduction of the counter-ion TFSI − and retards reduction of FSI − in comparison to the case when the additive VC is absent. The PYR14 + reduction is never observed with or without the additive. The 1st, 2nd, and 3rd electron affinities of the PYR14 + are −0.08, −0.36 and −3.65 eV, indicating little to large repulsive behavior against electrons. The opposite is observed for the two negative ions, FSI − and TFSI − , which yield 1st electron affinities of 1.73 and 1.83 eV, respectively. Reactions obtained under open circuit conditions. Dissociation mechanisms are presented for all IL components reduced at the IL/Li-metal interface.
Electrochemistry↗
Rationally Designed Lithium Ion Batteries Towards Displacing Internal Combustion Engines
Group14 Technologies is leading a word-class team composed of Cabot Corporation, Silatronix, Arkema, Pacific Northwest National Laboratories, and Farasis Energy to research, fabricate, test and demonstrate lithium-ion batteries (LIB) implementing ≥30% silicon-carbon (Si-C) composite anode material achieving aggressive next generation automotive energy targets.
25 ENERGY STORAGE↗
Characterization of pitch carbon coating properties affecting the electrochemical behavior of silicon nanoparticle lithium-ion battery anodes
Silicon is an exciting material for next-generation lithium-ion battery anodes, due to its high theoretical capacity and availability, but its widespread implementation has been limited by extensive volume changes during cycling that causes mechanical damage and limits cycle life. One approach to mitigating these deleterious effects while still maintaining silicon's benefits is the addition of a pitch carbon coating to nanometer-sized silicon particles. Here, in this study, we present characterization of pitch-coated silicon electrodes without annealing and annealed at 700 °C and 1000 °C to determine the optimum temperature treatment, as well as pitch-only and silicon-only electrodes with and without annealing to elucidate the impacts of each component on early electrochemical behavior. Using Fourier transform infrared and Raman spectroscopies, atomic force and scanning spreading resistance microscopy, and electrochemical analysis, we find 700 °C to be the optimal annealing temperature, as amorphous carbon is created, which improves conductivity prior to cycling and facilitates ion storage during cycling that increases capacity. We also present in situ Raman spectroscopy data demonstrating the heterogeneous aging that occurs across the electrode surface during cycling.
25 ENERGY STORAGE↗
Siloxane Deposition on the Ni-YSZ Solid Oxide Fuel Cell Anode Exposed to Bio-Syngas
Siloxane, a common contaminant present in biogas, is known for adverse effects on cogeneration prime movers. In this study, the siloxane deposition products and mechanism in the solid oxide fuel cell nickel-yttria stabilized zirconia (Ni-YSZ) anode are investigated analytically and experimentally. An SOFC with Ni-YSZ anode and pure Ni/YSZ pellets were exposed to a simulated biogas-reformate fuel with octamethylcyclotetrasiloxane (D4) contamination at 750 °C. The electrochemical characterization results show that the SOFCs performance degradation caused by D4 contamination is irreversible. Morphology and XRD results illustrate that silicon and carbon deposition can both be detected in the anode and pellets. Graphite, SiC and SiO2 are all possible products based on the results of XRD test. Here, according to the formation of graphite and SiC, the new mechanism suggests that carbon is also an essential factor in siloxane contamination of Ni-YSZ anodes besides silicon, which can be explained by the catalytic and electrochemical analysis.
25 ENERGY STORAGE↗
High Purity and Reduced Defects Hard Carbon Synthesis for Sodium-Ion Batteries
Hard carbon (HC) is the state-of-the-art anode material for sodium-ion batteries; however, the high-temperature carbonization of precursors (>1100 °C) often introduces inorganic impurities, an issue that remains largely underexplored. Here, we report a simple synthesis strategy for producing high purity HC by carbonizing a cellulose-derived precursor at 1400 °C under a slightly reducing Ar–H2 atmosphere on a graphite substrate, thereby eliminating the aluminum contamination observed during conventional carbonization on an alumina substrate under Ar. In addition, the modified synthetic condition reduces surface defects and the concentration of oxygen-containing functional groups, thereby altering the interphase formation on the HC surface. At a current density of 20 mA g−1, the impurity-rich HC exhibited an initial coulombic efficiency (ICE) of 74.1% and a reversible capacity of 248.8 mAh g−1. In sharp contrast, the high purity HC delivered a significantly improved ICE of 90.1% and a reversible capacity of 345.1 mAh g−1. These results underscore the critical importance of impurity and defect control during HC synthesis and highlight the clear electrochemical advantages of high purity HC with reduced defects for sodium-ion battery anodes.
Harshita, Lohanni↗