Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “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.

At least 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Evaluating Contributions of Pitch-Carbon Coating to Improved Stability of Si Anodes Through Voltage-Resolved Multi-Phase Characterization

Silicon nanoparticles have emerged as a promising alternative to graphite to improve the energy density of next-generation lithium-ion battery anodes. Nano-sized Si domains facilitate rapid ion transport and minimize particle-scale mechanical degradation, but also exhibit increased (electro)chemical reactivity with Li-ion electrolyte components due to their high surface area. We have previously demonstrated that surface modification of Si nanoparticles with pitch-carbon is an effective strategy to reduce these parasitic reactions. In the present work, we holistically evaluate the mechanistic contribution of pitch-carbon coating to the observed stability improvement over uncoated Si. We utilize coupled in situ and ex situ methods to probe changes to solid-surface, volatile headspace, and gas-phase chemistry occurring during initial cycling. Measurements taken at targeted potentials associated with electrolyte species reduction enables the decoupling of specific reaction pathways tied to interfacial stability. Further, we demonstrate the non-trivial role of gas reconsumption in dictating the nature of the passivating surface layer evolved on both uncoated and pitch-coated Si. This multi-phase analysis offers insights into the mechanism of effective surface passivation, which may be applied to inform future Si material development.

ENERGY STORAGE↗
DOE OSTI2022

Hydrogenated and Carbon-coated Na2Ti6O13 Nanowires as High-Rate Anode Materials for Lithium Ion Batteries

The main disadvantage for sodium titanate as an anode material for LIBs is its low electronic conductivity, resulting in poor rate capability. Several approaches have been taken in an attempt to improve the electronic conductivity of sodium/lithium titanate, such as electronic material coating/mixing, ionic doping, comminution, etc.; but as of yet there has been no uniform carbon coating reported on sodium titanate for LIBs. In this work, we detail a facile technique to create uniform thin carbon coating layers on Na2Ti6O13 nanowires (NTO-C). In addition, we also explored self-doped Ti3+ on carbon coated Na2Ti6O13 nanowires (H-NTO-C) in an effort to further improve its electronic conductivity. The detailed results of the synthesis, characterization, and electrochemical performance of the NTO-based materials (NTO, NTO-C and H-NTO-C) will be presented.

25 ENERGY STORAGE↗
DOE OSTI2023

Carbon Scaffold Architectures for Stable Lithium Metal Anodes

In light of the skyrocketing demand for electric vehicles and consequent need for high-performing lithium-ion batteries, there has been significant research into the creation of a battery with a lithium metal anode due to its high theoretical capacity and energy density. Unfortunately, nonuniform lithium deposition and consequent dendrite growth diminish performance and pose a safety risk. To combat this, lightweight carbon scaffolds are being developed to stabilize the electric field of these batteries and induce uniform deposition through rational design at the nano-, micro-, and meso- scales. However, there is a paucity of research on the impacts of macroscale scaffold topology on lithium cycling performance. Here, we report the creation of two graphite-based scaffolds with distinct 3D topologies: one a series of triangular prisms and one a series of rectangular prisms. Coin cells were made using these scaffolds and cycled at a current of 1mA/cm2 for 50 cycles to test the performance. The triangular topology was found to outperform the rectangular topology in terms of both potential magnitude and stability during cycling. Disassembling the cells revealed more even lithium deposition on the rectangular scaffold; however, some of the rectangular prisms were broken while all the triangular prisms remained intact. Last, future experiments are proposed regarding the scaffold spacing and mass of the cells in order to isolate the topological impact.

25 ENERGY STORAGE↗
DOE OSTI2023

Scale-up Production of Graphene Monoxide for Next-Generation LIB Anodes (AMMTO Final Report)

COnovate, LLC has developed a patented material called graphene monoxide and demonstrated that its unique chemical and crystal structure enables lithium-ion batteries (LIB) with greater specific capacity, safer and faster charging, and better low temperature performance than the industry standard. The current capability gap with COnovate’s technology is to scale up this new active anode material, developing processing technology to commercially relevant levels. This project will develop the means for progressive scale-up to 100g, 1kg, and 10kg levels, incorporating industrial synthesis and processing technologies, and deliver an industrial procedure/batch record draft for use by potential full-scale manufacturers to develop metric-ton production levels. The project goals of 10kg production and industrial procedure for full-scale production are necessary for COnovate’s customers to adequately evaluate and adopt their technology, and to pursue purchase orders for tons of material. MERF will confirm material analytics and performance in half cell tests during scaling and deliver materials to COnovate for QA/QC testing during the iterative scale up efforts. The final product batches will be delivered to COnovate for battery assembly and lifetime testing.

25 ENERGY STORAGE↗
DOE OSTI2024

Tritium Extraction from FLiBe using a Permeation Against Vacuum (PAV): Impact of Surface Potentials, Currents, and Coupling PAV to Sacrificial Anodes

Savannah River National Laboratory (SRNL) is exploring a concept of pairing a LiF-BeF2 (FLiBe) immersed Permeation Against Vacuum (PAV) tritium extraction system with a sacrificial anode. Several fusion concepts utilize FLiBe for tritium breeding, and breeding of tritium would occur from neutron interactions with the Li component, creating corrosive TF and/or T2. In absence of a redox buffered system, the TF would be able to attack containment materials until neutralized. One way to neutralize TF is to contact it with an active metal such as Be or Li which would preferentially combine with the fluorine in the TF to form BeF2 or LiF, respectively, and resulting in T2. When the active metal (e.g., Be) is oxidized, it will provide electrons, when T in TF is reduced and forms T2, it needs electrons. SRNL proposes to electrically link these two reactions and with the PAV to help drive the reactions faster than on their own and potentially increase T2 dissociation. In a soluble redox salt buffered system, it is expected that with sufficient buffering, T2, may form more rapidly and the core components would be more protected, but the soluble redox salt buffer would need to be occasionally regenerated, which could be accomplished by again contacting the salt with an active metal such as Be or Li, although in this case the cathodic reaction would be electrons coming from the shift in oxidative state of the redox buffer. The exploration of potential and current effects on the PAV and impacts of redox agents will be discussed.

Olson, Luke C.↗
DOE OSTI2024

Synthesizing Highly Crystalline Graphite Powder from Bulk Polyethylene Waste for Lithium-Ion Battery Anodes

Upcycling plastic waste into graphite can potentially be used, in conjunction with other methods, to manage existing waste materials and diversify graphite supply chains. However, synthesizing large quantities of crystalline graphite powder from plastic waste, particularly polyethylene (PE), remains a challenge because PE decomposes into light gases during thermal processing, and simple methods do not exist at any appreciable size scale to address this challenge. In this work, a method is developed for air processing bulk forms of PE waste to create a stable carbon char that does not readily decompose during high-temperature processing. This method employs solid additives in the form of salts, which are combined with the PE melt during air processing to increase the effective surface area of the melt and improve the oxygen-driven chemistry that stabilizes the PE for high-temperature processing. After removing the solid salt additives from the PE-derived char, it is converted into a highly crystalline bulk graphite powder using a Fe-based low-temperature (<1500 °C) catalytic process. The PE-derived graphite powder showed excellent electrochemical performance as an anode material for lithium-ion batteries (LIBs) with a capacity of up to 302 mAh/g at 0.5 discharge/charge cycles per hour (0.5 C) and capacity retention of 100% after 415 cycles.

Huynh, Ngoc Tien↗
DOE OSTI2024

Synthesizing Highly Crystalline Graphite Powder for Lithium-Ion Battery Anodes from Bulk Polyethylene Waste

Upcycling plastic waste into graphite can potentially be used to manage existing waste materials and diversify graphite supply chains. However, synthesizing large quantities of crystalline graphite powder from plastic waste, particularly polyethylene (PE), remains a challenge because PE decomposes into light gases during thermal processing, and simple methods do not exist at any appreciable size scale to address this challenge. In this work, a method is developed for air processing bulk forms of PE waste to create a stable carbon char, then be converted into a highly crystalline bulk graphite powder using a Fe-based catalytic process. The PE-derived graphite demonstrates excellent electrochemical performance as an anode material for lithium-ion batteries.

Gao, Yuan↗
DOE OSTI2024

Synthesizing Highly Crystalline Graphite Powder from Bulk Polyethylene Waste for Lithium-Ion Battery Anodes

Upcycling plastic waste into graphite can potentially be used, in conjunction with other methods, to manage existing waste materials and diversify graphite supply chains. However, synthesizing large quantities of crystalline graphite powder from plastic waste, particularly polyethylene (PE), remains a challenge because PE decomposes into light gases during thermal processing, and simple methods do not exist at any appreciable size scale to address this challenge. In this work, a method is developed for air processing bulk forms of PE waste to create a stable carbon char that does not readily decompose during high-temperature processing. This method employs solid additives in the form of salts, which are combined with the PE melt during air processing to increase the effective surface area of the melt and improve the oxygen-driven chemistry that stabilizes the PE for high-temperature processing. After removing the solid salt additives from the PE-derived char, it is converted into a highly crystalline bulk graphite powder using a Fe-based low-temperature (<1500 °C) catalytic process. The PE-derived graphite powder showed excellent electrochemical performance as an anode material for lithium-ion batteries (LIBs) with a capacity of up to 302 mAh/g at 0.5 discharge/charge cycles per hour (0.5 C) and capacity retention of 100% after 415 cycles. This method illustrates there are opportunities for upcycling large quantities of PE waste to produce graphite powders.

Huynh, Ngoc Tien [NETL Site Support Contractor, Na↗
DOE OSTI2025

Advanced Processing of Coal and Coal Waste to Produce Graphite for Fast-Charging Lithium-Ion Battery Anode

The University of North Dakota (UND) Energy & Environmental Research Center (EERC), in collaboration with the UND Center for Process Engineering Research (CPER), conducted a project to validate two technologies capable of converting North Dakota lignite and lignite coal waste to high-quality graphite for fast-charging lithium-ion battery (LIB) anode. The project was conducted over about 3 years from April 7, 2022, to July 6, 2025. The two technological paths pursued in this project include path A – direct conversion of coal or coal waste to graphite by the upgraded carbon ores to products (UCOP) process being developed at the EERC and path B – lignite-derived coal tar pitch (CTP) conversion to graphite (CTP2G) process being developed at CPER. The results from this project validate the two technological approaches and are expected to be an integral part of a portfolio of emerging technologies for making high-quality graphite not only from North Dakota lignite, but from all ranks of U.S. domestic coal and coal waste resources. The quality of the graphite produced by these technologies is high enough for various applications, including batteries for the fast-growing electric vehicle industry, energy storage applications, electric arc furnace electrodes for steel production, and graphene production, among others. Although the two technologies can produce high-quality graphite, they are fundamentally different in that the UCOP technology provides a direct path to transform coal to graphite, while the CTP2G technology needs to go through a CTP intermediate and a coking process for the intermediate, which requires a special facility to accomplish. For application in the industry, the UCOP process is designed to be more flexible, with feedstock to include potentially any carbonaceous material such as all coal ranks and biochar, while the CTP2G process is designed to utilize CTP as the starting precursor. The key project accomplishments include the following: • Successful preparation of high-quality synthetic graphite from North Dakota lignite coal/coal wastes and lignite-derived CTP. • Patent application has been filed for the UCOP process and an internal invention disclosure has been filed for the CTP2G process. • The produced graphite performs better than a commercial battery-grade sample in LIB coin cells, especially fast-charging capability, stability, and long-duration cycling. • Coin-type Li-ion half-cells with CTP2G graphite showed excellent performance, with >370 mAh/g capacity, >90% initial coulombic efficiency, and 93%/67% retention at 1C/2C rate, which outperforms commercial graphite in charging speed, stability, and cycling. • Results of fabricated 18650 cells were consistent with the observations in coin cells. • Preliminary techno-economic analysis (TEA) estimates for the UCOP technology indicate a manufacturing cost of about $\$$39/kg based on 50-metric ton/year capacity. • Preliminary TEA estimates for the CTP2G technology indicate a market price of about $\$$7107/ton ($\$$7/kg) based on 22,000-ton/year production capacity.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Effect of Initial Structure on Performance of High-Entropy Oxide Anodes for Li-Ion Batteries

Two different high-entropy oxide materials were synthesized and studied as Li-ion battery anodes. The two materials have the same active metal constituents but different inactive elements which result in different initial crystalline structures: rock salt for (MgFeCoNiZn)O and spinel for (TiFeCoNiZn)3O4. Local structural studies of the metal elements in these two materials over extended electrochemical cycling reveal that the redox processes responsible for the electrode capacity are independent of the initial crystallographic structure and that the capacity is solely dependent on the initial random distribution of the metal atoms and the amount of active metals in the starting material.

25 ENERGY STORAGE↗
DOE OSTI2020

Topological Dirac Semimetal Phase in Bismuth Based Anode Materials for Sodium-Ion Batteries

Bismuth has recently attracted interest in connection with Na-ion battery anodes due to its high volumetric capacity. It reacts with Na to form Na 3 Bi which is a prototypical Dirac semimetal with a nontrivial electronic structure. Density-functional-theory based first-principles calculations are playing a key role in understanding the fascinating electronic structure of Na 3 Bi and other topological materials. In particular, the strongly-constrained-and-appropriately-normed (SCAN) meta-generalized-gradient-approximation (meta-GGA) has shown significant improvement over the widely used generalized-gradient-approximation (GGA) scheme in capturing energetic, structural, and electronic properties of many classes of materials. Here, we discuss the electronic structure of Na 3 Bi within the SCAN framework and show that the resulting Fermi velocities and s-band shift around the Γ point are in better agreement with experiments than the corresponding GGA predictions. SCAN yields a purely spin-orbit-coupling (SOC) driven Dirac semimetal state in Na 3 Bi in contrast with the earlier GGA results. Our analysis reveals the presence of a topological phase transition from the Dirac semimetal to a trivial band insulator phase in Na 3 Bi x Sb 1-x alloys as the strength of the SOC varies with Sb content, and gives insight into the role of the SOC in modulating conduction properties of Na 3 Bi.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Low-Cost and Portable Biosensor Based on Monitoring Impedance Changes in Aptamer-Functionalized Nanoporous Anodized Aluminum Oxide Membrane

We report a low-cost, portable biosensor composed of an aptamer-functionalized nanoporous anodic aluminum oxide (NAAO) membrane and a commercial microcontroller chip-based impedance reader suitable for electrochemical impedance spectroscopy (EIS)-based sensing. The biosensor consists of two chambers separated by an aptamer-functionalized NAAO membrane, and the impedance reader is utilized to monitor transmembrane impedance changes. The biosensor is utilized to detect amodiaquine molecules using an amodiaquine-binding aptamer (OR7)-functionalized membrane. The aptamer-functionalized membrane is exposed to different concentrations of amodiaquine molecules to characterize the sensitivity of the sensor response. The specificity of the sensor response is characterized by exposure to varying concentrations of chloroquine, which is similar in structure to amodiaquine but does not bind to the OR7 aptamer. A commercial potentiostat is also used to measure the sensor response for amodiaquine and chloroquine. The sensing response measured using both the portable impedance reader and the commercial potentiostat showed a similar dynamic response and detection threshold. The specific and sensitive sensing results for amodiaquine demonstrate the efficacy of the low-cost and portable biosensor.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

One-Step Spark Plasma Erosion Processing of Carbon-Coated Sn-Si Nanoparticles for Lithium-Ion Battery Anodes

High density portable energy storage is desirable owing to the energy requirements of portable electronics and electric vehicles. The Li-ion battery’s high energy density could be even further improved through the utilization of alternative materials (instead of carbon) for the anode, such as Sn or Si. Nonetheless, the large volume expansion upon lithiation, up to ~300% for Li 22 Si 5 , causes pulverization and rapid capacity degradation during cycling. Sn also forms a Li 22 Sn 5 compound with the equivalent stoichiometric Li capacity but with enhanced ductility. Nano-sized Si and Sn have demonstrated distinctive nanoscale properties, facilitating the retention of higher capacities, particularly when coated with carbon, which improves mechanical stability. To date, the methods of synthesizing coated Si, Sn, or Si-Sn alloyed nanoparticles are complicated, costly, and not readily scalable to meet the demands of cost-effective manufacturing. Spark plasma erosion in a hydrocarbon dielectric has been explored as a one-step process to produce Sn-Si alloy nanoparticles coated with a thin carbon film, offering a scalable and cost-effective processing route. The resulting Sn-Si particles exhibited a bi-modal size distribution at ~5 nm and ~500 nm and were carbon-coated, as intended, from the hydrocarbon dielectric breakdown. The spark-eroded nanoparticles were thoroughly characterized using TEM/EDS, XPS, AES, SSNMR, and TGA, and their improved electrochemical performance was assessed through half-cell experiments.

25 ENERGY STORAGE↗