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

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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Prospective Life Cycle Assessment of Synthetic Graphite Manufactured via Electrochemical Graphitization

Lithium-ion batteries (LIBs) are expected to play a crucial role in meeting many of the clean energy-related goals. Due to its electrical properties such as good conductance, chemical inertness, and corrosion resistance, graphite is a very popular anode for LIBs. Traditional methods of producing battery-grade graphite (high purity >99%) include processing naturally mined graphite or manufacturing synthetic graphite via the Acheson process, which converts soft amorphous carbons such as petroleum coke into graphite by subjecting it to high temperature (up to 3000 °C) for prolonged periods of times (3–5 days). However, due to a lack of abundant high purity natural graphite sources, synthetic graphite is the preferred choice for many LIBs. A new synthetic electrochemical graphitization method that subjects the amorphous carbon precursor submerged in a molten salt mixture to a constant cathodic polarization (against a graphitic anode) has been discovered that has significantly lower graphitization temperatures (~800 °C) and reduced graphitization time (3–6 h). Furthermore, the method can accept a higher variety of carbon precursors compared to the Acheson process. A prospective life cycle assessment (LCA) is conducted on this new method and compared against the traditional processes. The laboratory-scale demonstration of the method is used to build an inventory, which through various assumptions is scaled up to a commercial scale. An additional scenario is also considered with a biomass-derived carbon precursor for the graphite. The results from the LCA show that while the laboratory scale process is similar to the Acheson process and natural flake graphite in terms of impact, the scaled-up process is drastically better than the Acheson process in all environmental categories. Using a coconut shell-derived biomass precursor has a higher impact due to its manufacturing in Indonesia, as the Indonesian energy grid is highly fossil fuel dependent. Therefore, the biomass carbon may have a higher impact than petroleum coke dependent on the location of production of biomass-derived carbon black. The LCA has identified the molten salt—CaCl 2 —as a potential hotspot and suggests other salts should be considered. Accordingly, the new method shows promise in this early stage LCA in improving the environmental performance of graphite (and by relation LIBs) and therefore needs to be explored more in terms of its commercial viability.

25 ENERGY STORAGE↗
DOE OSTI2020

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↗
DOE OSTI2021

A new cyclic carbonate enables high power/ low temperature lithium-ion batteries

The modern lithium-ion battery (LIB) configuration was enabled by the "magic chemistry" between ethylene carbonate (EC) and graphitic carbon anode. Despite the constant changes of cathode chemistries with improved energy densities, EC-graphite combination remained static during the last three decades. While the interphase generated by EC protects the fragile graphitic structure, the intrinsic disadvantages of EC (high viscosity, high melting point, excessive interphase growth) lead to mediocre power density and poor performances of LIB at sub-zero temperatures, where lithium depositions form upon charging. Such performance compromises arise from the fundamental dilemma between requiring effective interphase protection and high impedance from excessive growth of interphase. In this work, we designed and synthesized a "double EC" molecule as electrolyte additive to resolve the above dilemma. Erythritol bis(carbonate) (EBC) possesses lower LUMO energy level than EC and hence tends to decompose prior to EC reduction, but its weak solvation toward Li + restricts the extent of its reduction, thus minimizing the interphase thickness and the corresponding impedances. Electrolytes containing EBC enables both the charging and discharging of ampere-size LIB pouch cells at sub-zero temperatures from 0 to -20°C, demonstrating that the key approach to improve low temperature performances lies in how to tailor interphasial chemistry rather than the bulk electrolyte composition.

25 ENERGY STORAGE↗
DOE OSTI2021

Robust Solid/Electrolyte Interphase (SEI) formation on Si Anodes Using Glyme-based Electrolytes

Silicon (Si) is the most naturally abundant element possessing 10-fold theoretical capacity than graphitebased anodes. The practicality of implementing Si anodes is, however limited by the unstable solidelectrolyte interphase (SEI) and anode fracturing during continuous lithiation/delithiation. We demonstrate that glyme-based electrolytes (GlyEls) assure a conformal SEI on Si and keep the Si ‘fracture-free’. Benchmarking against the optimal, commonly-used carbonate electrolyte with the fluoroethylene carbonate (FEC) additive, Si anode cycled in a GlyEl exhibits reduced early parasitic current (by 62.5%) and interfacial resistance (by 72.8%), while the cell capacity retention is promoted by >7% over a course of 110 cycles. The mechanistic investigation by X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX) indicates GlyEl enriches Si SEI with elastic polyether but diminishes its carbonate species. Glyme-based electrolytes prove viable in stabilizing the SEI on silicon for future high energy density lithium-ion batteries.

Yang, Guang↗
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 OSTI2020

Assembling Si 2 BN nanoribbons into a 3D porous structure as a universal anode material for both Li- and Na-ion batteries with high performance

The development of anode materials is critical to the success of sodium ion batteries (SIBs). Because of the size difference between Li and Na, the commercial anode material graphite in Li-ion batteries does not work for Na-ion batteries. Thus, it will be ideal if some universal anode materials could work for both Li- and Na-ion batteries with high performance. Inspired by a recent study on the high performance of a 2D-Si 2 BN sheet as an anode material for Li-ion batteries, we design a three dimensional (3D) porous structure by using the nanoribbons of a Si 2 BN sheet as building blocks. Based on the state-of-the-art ab initio calculations, we find that the resulting 3D porous Si 2 BN structure is stable chemically, dynamically and thermally, exhibiting a high specific capacity of 512.42 (341.61 mA h g -1 ), a low voltage of 0.27 V (0.15 V), a small volume expansion of 2.5% (2.7%), and a low migration energy barrier of 0.44 eV (0.19 eV) for Li- (Na-) ion batteries. Finally, these intriguing features, together with the light mass and rich abundance of Si, B and N, suggest that the 3D porous Si2BN structure is a promising candidate for the anode material of both Li- and Na-ion batteries.

36 MATERIALS SCIENCE↗
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 OSTI2021

Interfaces in all solid state Li-metal batteries: A review on instabilities, stabilization strategies, and scalability

With technological advancements in electrochemical energy storage systems increasing at a spectacular rate, batteries equipped with a lithium anode hold the key towards unlocking high energy densities. While lithium-ion batteries with layered anodes (e.g. graphite) and liquid organic electrolytes have been ubiquitous in portable electronics, electric vehicles, and grid applications, all solid-state batteries that use the combination of a lithium anode and a solid-state electrolyte (SSE) will further advance the present technology. The underlying challenge that limits the successful development of all solid-state batteries (ASSBs) is dictated largely by the highly reactive interfaces at the anode/SSE and the cathode/SSE interface. In this comprehensive review, we present an overview of the following: (i) characterization of the electrode/SSE interface via multimodal characterization, which include X-ray-, electron-, neutron-, optical-, and computation-based methods: (ii) parasitic reactions that occur from chemical, mechanical or electrochemical instabilities and interfacial engineering strategies for improving the stability of these interfaces classified by the class of inorganic SSEs (sulfide-, NASICON-, and garnet-type SSEs); (iii) laboratory-to-industry scale processing perspectives of SSEs; (iv) scalability and manufacturing aspects of current interfacial strategies; and (v) the prospects of all ASSBs within the context of extreme fast charging capability. Here, this review seeks to highlight key efforts in the field of ASSBs, by focusing particularly on stabilizing the electrode/SSE interfaces, which will help to bridge fundamental studies to technological relevance.

25 ENERGY STORAGE↗
DOE OSTI2021

Lithium substituted poly(amic acid) as a water-soluble anode binder for high-temperature pre-lithiation

Multifunctional binders hold great promise in advanced electrode designs for both fundamental research and practical utilization of lithium-ion batteries (LIBs). The reactions between Si/SiO x -dominated anodes with lithium are expected to be exothermic in principle, while the thermal tolerance along with the volume change makes high-temperature binders attractive for large scale roll-to-roll manufacturing. For instance, if a high temperature binder is also water soluble, it can be compatible with the current graphite-based anode manufacturing process. In this work, we present a water-soluble poly(amic acid)-based binder, which can withstand high temperature for industrial pre-lithiation process and effectively hold active materials together during repeated charge and discharge cycles. This lithium substituted poly(amic acid) binder (denoted as Li-Pa) can serve as a drop-in replacement for environmentally friendly electrode fabrication in large scale by providing aqueous solubility, exceptional thermal stability and mechanical flexibility.

25 ENERGY STORAGE↗
DOE OSTI2021

Dual functionality of over-lithiated NMC for high energy silicon-based lithium-ion batteries

Owing to their high specific capacity and suitably low operating potential, silicon-based anodes are an attractive alternative to graphite in next-generation lithium-ion batteries. However, silicon anodes suffer from low initial coulombic efficiency and fast capacity decay, limiting their widespread application. Pre-lithiation strategies are highly appealing to compensate for irreversible active lithium loss and to boost the cell energy density. In this work, we maximize the cell energy density by direct pre-lithiation of the NMC (LiNi 0.5 Mn 0.3 Co 0.2 O 2 ) cathode to Li 1+x NMCO 2 without introducing inactive deadweight to either electrode. First, we demonstrate that Li 1+x NMCO 2 can be synthesized chemically, via reaction between NMC and lithium napthalide, and electrochemically. The NMC cathode is tolerant of a one-time over-lithiation up to 60 mA h g NMC -1 , giving capacity retention on par with untreated NMC in half cell electrochemical cycling. Using synchrotron X-ray absorption spectroscopy (ex situ) and diffraction (in situ), we demonstrate that higher amounts of over-lithiation lead to local structure distortion – driven by transition metal reduction to Jahn–Teller active Mn 3+ and Co 2+ – as well as bulk structural hysteresis during over-lithiation and layer “buckling” that increases the amount of lithium extracted from the structure in the charged state. The Li 1+x NMCO 2 with low-to-moderate over-lithiation capacity (23, 46, and 70 mA h g NMC -1 ) is proven to be a highly effective dual-purpose lithium source and cathode material in full cell tests with a commercially relevant Si–graphite anode. These cells show higher capacity, superior cycle life, and improved coulombic efficiencies when compared to those with stoichiometric NMC cathodes. Finally, this study introduces a new and simple method to pre-lithiate layered transition metal oxide cathodes, opening up new possibilities for the development of high energy density lithium-ion batteries with next-generation anodes.

25 ENERGY STORAGE↗
DOE OSTI2023

A Materials Perspective on Direct Recycling of Lithium-Ion Batteries: Principles, Challenges and Opportunities

As the dominant means of energy storage technology today, the widespread deployment of lithium-ion batteries (LIBs) would inevitably generate countless spent batteries at their end of life. From the perspectives of environmental protection and resource sustainability, recycling is a necessary strategy to manage end-of-life LIBs. Compared with traditional hydrometallurgical and pyrometallurgical recycling methods, the emerging direct recycling technology, rejuvenating spent electrode materials via a non-destructive way, has attracted rising attention due to its energy efficient processes along with increased economic return and reduced CO 2 footprint. This review investigates the state-of-the-art direct recycling technologies based on effective relithiation through solid-state, aqueous, eutectic solution and ionic liquid mediums and thoroughly discusses the underlying regeneration mechanism of each method regarding different battery chemistries. It is concluded that direct regeneration can be a more energy-efficient, cost-effective, and sustainable way to recycle spent LIBs compared with traditional approaches. Additionally, it is also identified that the direct recycling technology is still in its infancy with several fundamental and technological hurdles such as efficient separation, binder removal and electrolyte recovery. Finally, in addressing these remaining challenges, this review proposes an outlook on potential technical avenues to accelerate the development of direct recycling toward industrial applications.

25 ENERGY STORAGE↗
DOE OSTI2020

Advanced electrolytes for fast-charging high-voltage lithium-ion batteries in wide-temperature range

LiNixMnyCo1-x-yO2 (NMC) cathode materials with Ni=0.8 have attracted great interest for application in high energy-density lithium (Li)-ion batteries (LIBs) because of their high specific capacities at high voltages. However, the practical application of Ni-rich NMC in LIBs under high charge voltages (e.g. 4.4 V and above) still faces big challenges due to the severe capacity fading, which is directly related to the instability of the cathode/electrolyte interface. In this work, we develop new localized high-concentration electrolytes (LHCEs) based on carbonate solvents, which are compatible with graphite (Gr) anode and have a high oxidation potential over 4.9 V vs. Li/Li+. The optimal LHCE enables the Gr||NMC811 cells with 2.8 mAh cm-2 cathode areal capacity loading to achieve an excellent cycling stability over 600 cycles with a capacity retention of 94.2 % under a charge cut-off voltage of 4.4 V at 25 ?C, good rate capabilities under fast charging or discharging up to 3C rate, and superior low-temperature discharge performance down to -30 ?C with a capacity retention of 85.6% at C/5 rate. The findings in this work shed light a very promising strategy to develop new electrolytes for practical high-energy LIBs with Ni-rich NMC cathodes.

Zhang, Xianhui↗
DOE OSTI2023

A Systematic Study on the Effects of Solvating Solvents and Additives in Localized High‐Concentration Electrolytes over Electrochemical Performance of Lithium‐Ion Batteries

Abstract Localized high‐concentration electrolytes (LHCEs) based on five different types of solvents were systematically studied and compared in lithium (Li)‐ion batteries (LIBs). The unique solvation structure of LHCEs promotes the participation of Li salt in forming solid electrolyte interphase (SEI) on graphite (Gr) anode, which enables solvents previously considered incompatible with Gr to achieve reversible lithiation/delithiation. However, the long cyclability of LIBs is still subject to the intrinsic properties of the solvent species in LHCEs. Such issue can be readily resolved by introducing a small amount of additive into LHCEs. The synergetic decompositions of Li salt, solvating solvent and additive yield effective SEIs and cathode electrolyte interphases (CEIs) in most of the studied LHCEs. This study reveals that both the structure and the composition of solvation sheaths in LHCEs have significant effect on SEI and CEI, and consequently, the cycle life of energetically dense LIBs.

Jia, Hao↗
DOE OSTI2023

A Systematic Study on the Effects of Solvating Solvents and Additives in Localized High‐Concentration Electrolytes over Electrochemical Performance of Lithium‐Ion Batteries

Abstract Localized high‐concentration electrolytes (LHCEs) based on five different types of solvents were systematically studied and compared in lithium (Li)‐ion batteries (LIBs). The unique solvation structure of LHCEs promotes the participation of Li salt in forming solid electrolyte interphase (SEI) on graphite (Gr) anode, which enables solvents previously considered incompatible with Gr to achieve reversible lithiation/delithiation. However, the long cyclability of LIBs is still subject to the intrinsic properties of the solvent species in LHCEs. Such issue can be readily resolved by introducing a small amount of additive into LHCEs. The synergetic decompositions of Li salt, solvating solvent and additive yield effective SEIs and cathode electrolyte interphases (CEIs) in most of the studied LHCEs. This study reveals that both the structure and the composition of solvation sheaths in LHCEs have significant effect on SEI and CEI, and consequently, the cycle life of energetically dense LIBs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Revealing causes of macroscale heterogeneity in lithium ion pouch cells via synchrotron X-ray diffraction

Heterogeneous battery performance is a critical issue for maximization of cell lifetime capacity and safety. Using high energy synchrotron X-ray diffraction, the influence of charge rate, voltage limit, uneven stack pressure, and gas generation on the lithium transport properties was quantified in single-layer graphite/LiNi 0.5 Mn 0.3 Co 0.2 O 2 pouch cells. A freshly formatted cell tracked in operando during initial fast charge cycles indicated variable position-dependent performances, while lateral mapping showed a significant fast charge (6C) heterogeneity compared to slow charge (C/2). Pressure effects were non-dominant compared to charge rate. Maps of previously aged and rested cells indicate that lateral heterogeneity slowly equilibrates at rest, but regenerates upon further cycling at fast charge rate. Furthermore, an unformatted cell was mapped at charge and discharge during its first formation cycle to analyze the effect of byproduct gases on the heterogeneous lithium transport. Gas was observed as randomly interspersed “bubbles” which locally hindered lithium intercalation and caused significant heterogeneity. Electrode architectures and charging protocols that promote homogeneous intercalation are critical for predictable high-performance and long-life batteries.

25 ENERGY STORAGE↗