Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “graphite anodes”

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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Microstructure Scale Lithium-Ion Battery Modeling: Part II. On In-Plane Heterogeneities and the Mechanisms that Regulate Them

Li-ion batteries performance and degradation are typically modeled at the macroscopic scale, that is neglecting in-plane heterogeneities that can arise from non-uniform electrode microstructures. Herein, a microstructure scale electrochemical model is used to quantify the impact of microstructure heterogeneity on cell performance during fast charging. The model predicts the electrolyte and solid concentration in-plane standard deviation can reach, respectively, ≈200 mol·m −3 and 6–7 kmol·m −3 locally. Further, the intercalation current density in-plane relative standard deviation can reach extremely high values, around 100% in the cathode and well above 100% in the anode graphite. These denote highly non-uniform lithiation rates and material utilization within each slice of the microstructure along the cell thickness. Non-uniform curvatures, at the particle scale (surface roughness) and between particles (size distribution), were found to initiate these in-plane heterogeneities, while an OCP-induced mechanism subsequently regulates them. The present model provides new insights into small length scale heterogeneity impact on battery performance not available with standard macro-scale/P2D modeling.

25 ENERGY STORAGE↗
DOE OSTI2020

Extreme Fast Charging Lithium-Ion Batteries (Final Technical Report)

The objective of this research project is to develop, design, fabricate, and demonstrate lithium ion battery cells that optimize energy density, reduce cost, and demonstrate eXtreme Fast Charging (XFC) capabilities. The XFC capability of the cell will be determined by the final specific energy of the cell after completing 500 6C charge /1C discharge cycles. Over the first 18 months of the project, over 800 cells were produced in groups of 20 cells to determine the optimum configuration of following parameters to optimized XFC performance: (1) Graphite anode material optimization (2) Electrolyte and additive optimization (3) Electrode and cell design optimization. In the final 6 months of the project, over 200 optimized cells were produced that featured optimized parameters from each of the independent studies. The final optimized cells exhibited a final specific energy of 150 Wh/kg, meeting the DOE project goal, but failing to meet the initial specific energy requirement of 180 Wh/kg.

25 ENERGY STORAGE↗
DOE OSTI2026

Jumpstart Opportunities to Unleash Leadership in Energy Storage (JOULES)

Current-generation Li-ion batteries with cobalt- and nickel-containing cathodes and graphite anodes are approaching performance and cost limits. In this program, 24M Technologies, Inc. (24M) is teaming with the Massachusetts Institute of Technology (MIT) and University of Michigan (UM) to develop low cost and fast charging sodium metal batteries with good low-temperature performance and high energy density, building upon previous work performed under ARPA-E programs. Key achievements include optimization of solid electrolyte and anode current collector, optimized cathode active materials, development of high-performance electrolyte formulations, and integration of these components into full cells. The cell design incorporates (1) an ultra-thick cathode (>9 mAh/cm 2 ) comprising advanced cobalt-free, sodium cathode active material, (2) advanced fast-charging electrolyte (up to 12 mS/cm) developed using machine learning and automated high-throughput screening technology by UM, and (3) ceramic modified separator that enable smooth Na transport and deposition, developed at MIT, enabling a high-energy density anode-free configuration and maximizing the energy density of sodium batteries. The team has successfully combined these approaches to sodium chemistry and paved the way to meeting the fast-charging, high-energy density, and low-cost requirements of next-generation drone, electric vertical take-off and -landing, and electric vehicle batteries. Performance for anode-free sodium cells developed under this program is more powerful than the commercial Li-ion batteries. The final deliverable cell design has achieved over 300 Wh/kg and volumetric energy density above 800 Wh/L (Table 1). Additionally, the team has achieved over (1) a lifetime of 340 cycles, (2) 80% capacity retention at -20 °C (compared 25 °C), and (3) the ability to fast charge to 80% SOC in 20 minutes.

25 ENERGY STORAGE↗
DOE OSTI2023

Optimized purification methods for metallic contaminant removal from directly recycled Li-ion battery cathodes

Metallic contaminants pose a significant challenge to the viability of directly recycling Li-ion batteries. To date, few strategies exist to selectively remove metallic impurities from mixtures of shredded end-of-life material (black mass; BM) without concurrently damaging the structure and electrochemical performance of the target active material. We herein present tailored methods to selectively ionize two major contaminants—Al and Cu—while retaining a representative cathode (LiNi 0.33 Mn 0.33 Co 0.33 O 2 ; NMC-111) intact. This BM purification process is conducted at moderate temperatures in a KOH-based solution matrix. We rationally evaluate approaches to increase both the kinetic corrosion rate and the thermodynamic solubility of Al 0 and Cu 0 , and evaluate the impact of these treatment conditions on the structure, chemistry, and electrochemical performance of NMC. Specifically, we explore the impacts of chloride-based salts, a strong chelating agent, elevated temperature, and sonication on the rate and extent of contaminant corrosion, while concurrently evaluating the effects on NMC. The reported BM purification process is then demonstrated on samples of “simulated BM” containing a practically relevant 1 wt% concentration of Al or Cu. Increasing the kinetic energy of the purifying solution matrix through elevated temperature and sonication accelerates the corrosion of metallic Al and Cu, such that ∼100% corrosion of 75 μm Al and Cu particles is achieved within 2.5 hr. Further, we determine that effective mass transport of ionized species critically impacts the efficacy of Cu corrosion, and that saturated Cl – hinders rather than accelerates Cu corrosion by increasing solution viscosity and introducing competitive pathways for Cu surface passivation. The purification conditions do not induce bulk structural damage to NMC, and electrochemical capacity is maintained in half-cell format. Testing in full cells suggests that a limited quantity of residual surface species are present after treatment, which initially disrupt electrochemical behavior at the graphite anode but are subsequently consumed. Process demonstration on simulated BM suggests that contaminated samples—which prior to treatment show catastrophic electrochemical performance—can be recovered to pristine electrochemical capacity. The reported BM purification method offers a compelling and commercially viable solution to address contamination, particularly in the “fine” fraction of BM where contaminant sizes are on the same order of magnitude as NMC and where traditional separation approaches are unfeasible. Thus, this optimized BM purification technique offers a pathway towards viable direct recycling of BM feedstocks that would otherwise be unusable.

25 ENERGY STORAGE↗
DOE OSTI2021

Atomistic-Scale Simulations on Graphene Bending Near a Copper Surface

Molecular insights into graphene-catalyst surface interactions can provide useful information for the efficient design of copper current collectors with graphitic anode interfaces. As graphene bending can affect the local electron density, it should reflect its local reactivity as well. Using ReaxFF reactive molecular simulations, we have investigated the possible bending of graphene in vacuum and near copper surfaces. We describe the energy cost for graphene bending and the binding energy with hydrogen and copper with two different ReaxFF parameter sets, demonstrating the relevance of using the more recently developed ReaxFF parameter sets for graphene properties. Moreover, the draping angle at copper step edges obtained from our atomistic simulations is in good agreement with the draping angle determined from experimental measurements, thus validating the ReaxFF results.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Recent Developments of Tin (II) Sulfide/Carbon Composites for Achieving High-Performance Lithium Ion Batteries: A Critical Review

The ever-increasing worldwide energy demand and the limited resources of fossil have forced the urgent adoption of renewable energy sources. Additionally, concerns over CO 2 emissions and potential increases in fuel prices have boosted technical efforts to make hybrid and electric vehicles more accessible to the public. Rechargeable batteries are undoubtedly a key player in this regard, especially lithium ion batteries (LIBs), which have high power capacity, a fast charge/discharge rate, and good cycle stability, while their further energy density improvement has been severely limited, because of the relatively low theoretical capacity of the graphite anode material which is mostly used. Among various high-capacity anode candidates, tin (II) sulfide (SnS 2 ) has been attracted remarkable attention for high-energy LIBs due to its enormous resource and simplicity of synthesis, in addition to its high theoretical capacity. However, SnS 2 has poor intrinsic conductivity, a big volume transition, and a low initial Coulombic efficiency, resulting in a short lifespan. SnS 2 /carbon composites have been considered to be a most promising approach to addressing the abovementioned issues. Therefore, this review summarizes the current progress in the synthesis of SnS 2 /carbon anode materials and their Li-ion storage properties, with special attention to the developments in Li-based technology, attributed to its immense current importance and promising prospects. Finally, the existing challenges within this field are presented, and potential opportunities are discussed.

25 ENERGY STORAGE↗
DOE OSTI2023

Catalytic Graphitization of Biocarbon for Lithium‐Ion Anodes: A Minireview

Abstract The demand for electrochemical energy storage is increasing rapidly due to a combination of decreasing costs in renewable electricity, governmental policies promoting electrification, and a desire by the public to decrease CO 2 emissions. Lithium‐ion batteries are the leading form of electrochemical energy storage for electric vehicles and the electrical grid. Lithium‐ion cell anodes are mostly made of graphite, which is derived from geographically constrained, non‐renewable resources using energy‐intensive and highly polluting processes. Thus, there is a desire to innovate technologies that utilize abundant, affordable, and renewable carbonaceous materials for the sustainable production of graphite anodes under relatively mild process conditions. This review highlights novel attempts to realize the aforementioned benefits through innovative technologies that convert biocarbon resources, including lignocellulose, into high quality graphite for use in lithium‐ion anodes.

25 ENERGY STORAGE↗
DOE OSTI2023

Exploring the Storage Mechanism of Alkali Ions in Non-Graphitic Hard Carbon Anodes

This study aims to develop high-capacity hard carbon anode materials for alkali-ion batteries by controlling the microstructures of non-graphitic hard carbon through an annealing protocol and investigating the effects on the alkali-ion storage mechanisms using physical, chemical, and electrochemical analytical techniques. The hard carbon materials were synthesized at temperatures ranging from 900 °C to 1600 °C. Those synthesized at 1100 °C with high surface area and abundant defects exhibited the highest reversible capacity in Li- and K-ion systems, with the storage dominated by surface-adsorption mechanisms. In contrast, the hard carbon compounds prepared at 1400 °C with numerous curve-featured pores delivered the highest reversible capacity in the Na-ion system, indicating that these pores are the preferred Na-ion storage sites, particularly in low-voltage plateau regions. This study provides a comprehensive understanding of the relationship between microstructures and alkali-ion storage mechanisms in non-graphitic hard carbon and highlights the importance of tailoring the microstructures of hard carbon to achieve high specific capacity for the desired alkali-ion species.

25 ENERGY STORAGE↗
DOE OSTI2023

Nanoscale electrostatic control in ultraclean van der Waals heterostructures by local anodic oxidation of graphite gates

In an all-van der Waals heterostructure, the active layer, gate dielectrics and gate electrodes are assembled from two-dimensional crystals that have a low density of atomic defects. This design allows two-dimensional electron systems with very low disorder to be created, particularly in heterostructures where the active layer also has intrinsically low disorder, such as crystalline graphene layers or metal dichalcogenide heterobilayers. A key missing ingredient has been nanoscale electrostatic control, with existing methods for fabricated local gates typically introducing unwanted contamination. Here we describe a resist-free local anodic oxidation process for patterning sub-100 nm features in graphite gates, and their subsequent integration into an all-van der Waals heterostructure. We define a quantum point contact in the fractional quantum Hall regime as a benchmark device and observe signatures of chiral Luttinger liquid behaviour, indicating an absence of extrinsic scattering centres in the vicinity of the point contact. In the integer quantum Hall regime, we demonstrate in situ control of the edge confinement potential, a key requirement for the precision control of chiral edge states. In conclusion, this technique may enable the fabrication of devices capable of single anyon control and coherent edge-state interferometry in the fractional quantum Hall regime.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Updated Production Inventory for Lithium-Ion Battery Anodes for the GREET® Model, and Review of Advanced Battery Chemistries

The Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET®) model considers lithium-ion batteries with multiple anode materials. Synthetic graphite is the primary anode material used in the previous GREET versions, even as the model offered options to choose a lithium anode and/or a blended anode (blend of synthetic graphite and silicon). Yet, the inventory (material and energy flows) considered for these anodes is dated, and the anode options do not consider natural graphite, which is another important anode material for lithium-ion batteries. This report documents the material and energy flows for natural graphite anode production from raw material extraction to anode production – as incorporated in the updated GREET model. We also present a brief literature review on the current state of inventory for the other three anodes (synthetic graphite, silicon, and lithium), as well as updates made in the recent GREET model on material and energy flows associated with their respective production. Finally, this study provides a summary of advanced battery systems that may be alternatives to LIBs for use in future electric vehicles.

25 ENERGY STORAGE↗
DOE OSTI2020

Tin-graphene tubes as anodes for lithium-ion batteries with high volumetric and gravimetric energy densities

Limited by the size of microelectronics, as well as the space of electrical vehicles, there are tremendous demands for lithium-ion batteries with high volumetric energy densities. Current lithium-ion batteries, however, adopt graphite-based anodes with low tap density and gravimetric capacity, resulting in poor volumetric performance metric. Here, by encapsulating nanoparticles of metallic tin in mechanically robust graphene tubes, we show tin anodes with high volumetric and gravimetric capacities, high rate performance, and long cycling life. Pairing with a commercial cathode material LiNi0.6Mn0.2Co0.2O2, full cells exhibit a gravimetric and volumetric energy density of 590 W h Kg-1 and 1,252 W h L-1 , respectively, the latter of which doubles that of the cell based on graphite anodes. This work provides an effective route towards lithium-ion batteries with high energy density for a broad range of applications.

25 ENERGY STORAGE↗
DOE OSTI2022

Sustainable conversion of biomass to rationally designed lithium-ion battery graphite

The carbon net negative conversion of bio-char, the low value byproduct of pyrolysis bio-oil production from biomass, to high value, very high purity, highly crystalline flake graphite agglomerates with rationally designed shape and size tailored for lithium-ion battery energy storage material is reported. The process is highly efficient, 0.41 g/Wh; the energy content of its co-product of the process, bio-oil, exceeds that needed to power the process. It is shown that the shape of the starting material is retained during the transformation, allowing the ultimate morphology of the graphite agglomerates to be engineered from relatively malleable biomass. In contrast to commercial graphite production, the process can be performed at small scale with low equipment costs, enabling individual research laboratories to produce Li-ion grade graphite with customizable shape, size and porosity for Si/graphite composite and other graphite involved anodes. The mechanism of the graphitization of bio-char, a “non-graphitizable” carbon, is explored, suggesting the molten metal catalyst is absorbed into the pore structure, transported through and transforming the largely immobile biochar. Finally, the transformation of biomass to rationally designed graphite morphologies with Li-ion anode performance that closely mimic commercial shaped graphite is demonstrated.

09 BIOMASS FUELS↗
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 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 PE for high-temperature processing. After removal of the solid salt additives from the PE-derived char, it is converted into a highly crystalline bulk graphite powder using an Fe-based catalytic process. The PE-derived graphite anode in a lithium-ion coin cell showed a specific capacity of 345 mAh/g at 0.05C with an initial Coulombic efficiency of 87% and reversible capacity retention of ~100% at different current rates. It also showed a specific capacity of up to 313 mAh/g at 0.5 discharge/charge cycles per hour (0.5C) and Coulombic efficiency of 99.9% after 250 cycles, indicating excellent electrochemical performance as an anode material for lithium-ion batteries. This method illustrates that there are opportunities for upcycling large quantities of PE waste to produce graphite powders suitable for use in LIBs.

25 ENERGY STORAGE↗
DOE OSTI2021

The Quest for Stable Potassium‐Ion Battery Chemistry

Abstract Potassium‐ion batteries (KIBs) have attracted wide interest for energy storage because of the abundance of the electrode materials involved; however, their electrochemical performances are far behind what can be achieved from lithium‐ion batteries (LIBs) or sodium‐ion batteries (SIBs). Herein, key promising electrode and electrolyte materials for potassium‐ion batteries are identified, the coupled electrochemical reactions in the cell are investigated, and the compatibility between different materials is demonstrated to play the most important role. K 2 Mn[Fe(CN) 6 ] cathode can deliver a high capacity of ≈125 mAh g −1 and exceptional cycling stability over 61 000 cycles (≈9 months) if the side reactions from the anode can be prevented. Graphite is a good anode material but is subjected to degradation in traditional carbonate electrolytes. New concentrated electrolytes are developed and evaluated. A stable KIB system is demonstrated by coupling a stable K 2 Mn[Fe(CN) 6 ] cathode, a prepotassiated graphite anode with a concentrated electrolyte to achieve a high energy density of ≈260 Wh kg −1 (based on the active mass of cathode and anode) and good cycling of over 1000 cycles.

Wu, Xianyong↗
DOE OSTI2024

Carbon Ore-Derived Critical Materials for Clean Energy Technologies

Conference presentation at American Institute of Chemical Engineers (AIChE) Annual Meeting, San Diego, California, October 27–31, 2024. Trends in the manufacture of electric vehicles that use graphite-based LIBs are rising steeply in the United States and globally, but the U.S. domestic supply chains for graphite, the largest component in an LIB by mass, is severely limited and faces complicated geopolitical dynamics with foreign sources. Consequently, the United States has designated graphite as a critical mineral to focus attention and resources to develop technologies to meet the challenge of limited domestic graphite supply chains. Results obtained so far based on the UCOP process have successfully validated the technology at the laboratory scale, with the produced graphite material showing up to 95% degree of graphitization, high carbon purity of ~99.98%, residual ash content of ≤0.02%, negligible moisture, low trace elements, and high electrochemical stability. These results suggest that the emerging UCOP technology is a promising approach to effectively synthesize high-quality graphite from abundant coal and coal waste resources in the United States to create a sustainable domestic critical graphite supply chain. A brief description of the status of UCOP process development and representative results will be presented.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Coal and Coal Wastes to High-Quality Graphite for Lithium-Ion Battery Applications

Conference presentation for 2023 International Freiberg Conference on Circular Carbon Technologies, Rotterdam, Netherlands, September 24–29, 2023. To assist in meeting the global graphite supply limitations, this study aims to investigate efficient ways to synthesize high-quality graphite from abundant coal and coal waste resources that exist in many areas around the world. A recently developed upgraded coal-to-products (UCP) process has shown great promise in the ability to reduce coal-borne impurities and produce a graphitizable product that yields good quality graphite for LIB applications. Preliminary results show that the quality of coal-derived graphite obtained by the UCP process is similar to that of commercial flake graphite. Available results are presented and discussed as well as maturation plans and flexibility of the UCP technology.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Upgraded Coal to High-Quality Graphite for Lithium-Ion Battery Applications

Presentation for the World Conference on Carbon 2023, Cancun, Mexico, July 16–21, 2023. To assist in meeting the global graphite supply limitations, this study aims to investigate efficient ways to synthesize high-quality graphite from abundant coal resources that exist in many areas around the world. A recently developed upgraded coal-to-products (UCP) process has shown great promise in the ability to reduce coal-borne impurities and produce a graphitizable product that yields good-quality graphite for LIB applications. Preliminary results show that the quality of coal-derived graphite obtained by the UCP process is close to that of commercial LIB-grade graphite. Results are presented and discussed as well as maturation plans and flexibility of the UCP technology.

01 COAL, LIGNITE, AND PEAT↗