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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 793 records · Page 44

Defect-Engineered High-Entropy Spinel Oxide@Onion-Like Carbon Catalysts for High-Areal-Energy Rechargeable Zinc–Air Batteries

Rechargeable zinc-air batteries (ReZAB) have emerged as the next-generation batteries with several advantages over the conventional lithium-ion battery. In this work, single nanocrystals of inverse-type high-entropy spinel oxides (HESOx, particle size of 10−12 nm) confined in highly curved defective onion-like carbons (HESOx/OLC AT ) as efficient electrocatalysts for oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and ReZAB, have been synthesized. The HESOx materials were thoroughly characterized using several analytical techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), Raman, and electron paramagnetic resonance (EPR). HESOx/OLC AT catalyst was tested for ReZAB using literature-recommended parameters that would allow for real technological application. These parameters include a current loading of 10 mA cm −2 and a discharge areal energy density of 35 mWh cm geometric −2 , which maps a Li-ion battery pack-level specific energy of 120 Wh kg pack −1 . HESOx/OLC AT electrocatalysts allowed for continuous discharging and charging at a current loading of 10 mA cm −2 with discharge areal energy densities between 37 and 74 mWh cm geometric −2 , thus outperforming the recommended threshold of 35 mWh cm geometric −2 . Considering that most studies (>90%) hardly meet the recommended threshold for technological application of ReZAB, the present work represents one of the top-performing electrocatalysts for ReZAB. The excellent electrocatalytic properties of defect-rich HESOx/OLC AT toward ORR/OER and ReZAB are governed by the strong electronic modulation arising from d-π hybridization, the availability of multiple catalytic sites for intermediates, and weakened d-band centers of the rate-determining intermediates (i.e., *O adsorption for ORR and *OOH formation for OER) compared to the pristine HESOx. This work introduces an effective approach for the design and synthesis of single nanocrystals of high-entropy electrocatalysts for the development of low-cost, robust, and technologically relevant rechargeable zinc−air batteries.

25 ENERGY STORAGE↗

A High-Rate Lithium Manganese Oxide-Hydrogen Battery

Rechargeable hydrogen gas batteries show promises for the integration of renewable yet intermittent solar and wind electricity into the grid energy storage. Here, we describe a rechargeable, high-rate, and long-life hydrogen gas battery that exploits a nanostructured lithium manganese oxide cathode and a hydrogen gas anode in an aqueous electrolyte. The proposed lithium manganese oxide-hydrogen battery shows a discharge potential of ~1.3 V, a remarkable rate of 50 C with Coulombic efficiency of ~99.8%, and a robust cycle life. A systematic electrochemical study demonstrates the significance of the electrocatalytic hydrogen gas anode and reveals the charge storage mechanism of the lithium manganese oxide-hydrogen battery. This work provides opportunities for the development of new rechargeable hydrogen batteries for the future grid-scale energy storage.

25 ENERGY STORAGE↗

An Anode-Free Zn–MnO 2 Battery

Aqueous Zn-based batteries are attractive because of the low cost and high theoretical capacity of the Zn metal anode. However, the Zn-based batteries developed so far utilize an excess amount of Zn (i.e., thick Zn metal anode), which decreases the energy density of the whole battery. In this study, we demonstrate an anode-free design (i.e., zero-excess Zn), which is enabled by employing a nanocarbon nucleation layer. Electrochemical studies show that this design allows for uniform Zn electrodeposition with high efficiency and stability over a range of current densities and plating capacities. Using this anode-free configuration, we showcase a Zn–MnO 2 battery prototype, showing 68.2% capacity retention after 80 cycles. Our anode-free design opens a new direction for implementing aqueous Zn-based batteries in energy storage systems.

25 ENERGY STORAGE↗

Suppressing the Shuttle Effects with FeCo/SPAN Cathodes and High-Concentration Electrolytes for High-Performance Lithium–Sulfur Batteries

The shuttle effects and the sluggish redox kinetics are two of the main challenges in lithium–sulfur (Li–S) batteries, which significantly reduce the capacity of the batteries and restrict their commercialization. Herein, FeCo/sulfurized polyacrylonitrile (SPAN) is synthesized as a cathode material via the electrospinning technique and a further heat treatment. Synchrotron X-ray absorption spectroscopy confirmed the existence of Fe–S/Fe and Co–S bonds in FeCo/SPAN, which benefit the adsorptive and catalytic activities toward lithium polysulfides (LiPSs). Here, we further investigated the effect of electrolyte concentration in inhibiting the shuttle of LiPSs in Li–S batteries. Small-angle X-ray scattering (SAXS) reveals that more contact ion pairs are formed and fewer free solvent molecules exist with the increase of the electrolyte concentration, which can inhibit the dissolution and shuttle of LiPSs. Finally, the batteries assembled with high-concentration electrolytes (3 M LiTFSI in DOL/DME) exhibit a higher specific capacity retention compared to those assembled with low-concentration electrolytes. This work enriches the route to prepare Li–S batteries with the rational design of cathode materials and electrolytes.

25 ENERGY STORAGE↗

Optimized Electrolyte with High Electrochemical Stability and Oxygen Solubility for Lithium–Oxygen and Lithium–Air Batteries

Lithium-oxygen (Li-O2) batteries with high reversibility require a stable electrolyte against the side reactions with Li metal anode and reactive oxygen species. Moreover, an electrolyte which can effectively utilize the low partial pressure of oxygen in atmosphere has significance effect on the practical application lithium-air batteries. In this study, we developed a localized high concentration electrolyte (LHCE) using 1H,1H,5H-Octafluoropentyl 1,1,2,2-tetrafluoroethyl ether (OTE) as a diluent, which satisfies all these conditions at the same time. The OTE-based LHCE exhibits much improved electrochemical performances in Li-O2 batteries and Li-air batteries compared to the conventional electrolyte and high concentration electrolyte. The design principle of this novel electrolyte also provides an important guideline and reference for future researches of electrolytes in Li-O2 and Li-air batteries.

lithium air batteries, Localized high concentratio↗

High-Energy All-Solid-State Organic–Lithium Batteries Based on Ceramic Electrolytes

Recent studies have identified unique properties of organic battery electrode materials such as moderate redox potentials and mechanical softness which are uniquely beneficial for all-solid-state batteries based on ceramic electrolytes. Here, we further explore the promise of organic materials and demonstrate a sulfide electrolyte- based organic-lithium battery with a specific energy of 828 Wh kg –1 , rivaling the state-of- the-art of all-solid-state batteries. Two innovation steps are responsible for the accomplishment. First, the combination of lithium anode and the high-capacity cathode material pyrene-4,5,9,10-tetraone ensures a high theoretical specific energy. Second, the microstructure of the organic cathode is optimized with the introduction of cryomilling, a technique common to processing soft materials but not familiar to electrode fabrication. The cathode material utilization increases to 99.5% as a result, up from the 55–89% previously reported for ceramic electrolyte-based solid-state organic batteries. In conclusion, the improvement highlights the special requirements of solid-state organic electrodes for microstructural engineering while preserving the chemical integrity of components.

25 ENERGY STORAGE↗

Large Local Currents in a Lithium-Ion Battery during Rest after Fast Charging

Increasing electric vehicle (EV) adoption requires lithium-ion batteries that can be charged quickly and safely. Some EV batteries have caught on fire despite being neither charged nor discharged. While the lithium that plates on graphite during fast charging affects battery safety, so do the internal ionic currents that can occur when the battery is at rest after charging. These currents are difficult to quantify; the external current that can readily be measured is zero. Here we study a graphite electrode at rest after 6C fast charging using operando X-ray microtomography. We quantify spatially resolved current density distributions that originate at plated lithium and end in underlithiated graphite particles. The average current densities decrease from 1.5 to 0.5 mA cm -2 in about 20 min after charging is stopped. Surprisingly, the range of the stripping current density is independent of time, with outliers above 20 mA cm -2 . In conclusion, the persistence of outliers provides a clue as to the origin of catastrophic failure in batteries at rest.

25 ENERGY STORAGE↗

Co-Solvent Electrolyte Engineering for Stable Anode-Free Zinc Metal Batteries

We report anode-free metal batteries can in principle offer higher energy density, but this requires them to have extraordinary Coulombic efficiency (>99.7%). Although Zn-based metal batteries are promising for stationary storage, the parasitic side reactions make anode-free batteries difficult to achieve in practice. In this work, a salting-in-effect-induced hybrid electrolyte is proposed as an effective strategy that enables both a highly reversible Zn anode and good stability and compatibility toward various cathodes. The as-prepared electrolyte can also work well under a wide temperature range (i.e., from -20 to 50 °C). It is demonstrated that in the presence of propylene carbonate, triflate anions are involved in the Zn 2+ solvation sheath structure, even at a low salt concentration (2.14 M). The unique solvation structure results in the reduction of anions, thus forming a hydrophobic solid electrolyte interphase. The waterproof interphase along with the decreased water activity in the hybrid electrolyte effectively prevents side reactions, thus ensuring a stable Zn anode with an unprecedented Coulombic efficiency (99.93% over 500 cycles at 1 mA cm –2 ). More importantly, we design an anode-free Zn metal battery that exhibits excellent cycling stability (80% capacity retention after 275 cycles at 0.5 mA cm –2 ). This work provides a universal strategy to design co-solvent electrolytes for anode-free Zn metal batteries.

25 ENERGY STORAGE↗

Fluoride-Rich, Organic–Inorganic Gradient Interphase Enabled by Sacrificial Solvation Shells for Reversible Zinc Metal Batteries

Zinc metal batteries are strongly hindered by water corrosion, as solvated zinc ions would bring the active water molecules to the electrode/electrolyte interface constantly. Herein, we report a sacrificial solvation shell to repel active water molecules from the electrode/electrolyte interface and assist in forming a fluoride-rich, organic-inorganic gradient solid electrolyte interface (SEI) layer. Additionally, the simultaneous sacrificial process of methanol and Zn(CF 3 SO 3 ) 2 results in the gradient SEI layer with an organic-rich surface (CH 2 OC- and C 5 product) and an inorganic-rich (ZnF 2 ) bottom, which combines the merits of fast ion diffusion and high flexibility. As a result, the methanol additive enables corrosion-free zinc stripping/plating on copper foils for 300 cycles with an average coulombic efficiency of 99.5%, a record high cumulative plating capacity of 10 A h/cm 2 at 40 mA/cm 2 in Zn/Zn symmetrical batteries. More importantly, at an ultralow N/P ratio of 2, the practical VO 2 //20 mu m thick Zn plate full batteries with a high areal capacity of 4.7 mAh/cm 2 stably operate for over 250 cycles, establishing their promising application for grid-scale energy storage devices. Furthermore, directly utilizing the 20 μm thick Zn for the commercial-level areal capacity (4.7 mAh/cm 2 ) full zinc battery in our work would simplify the manufacturing process and boost the development of the commercial zinc battery for stationary storage.

25 ENERGY STORAGE↗

Machine-learning-revealed statistics of the particle-carbon/binder detachment in lithium-ion battery cathodes

The microstructure of a composite electrode determines how individual battery particles are charged and discharged in a lithium-ion battery. It is a frontier challenge to experimentally visualize and, subsequently, to understand the electrochemical consequences of battery particles’ evolving (de)attachment with the conductive matrix. Herein, we tackle this issue with a unique combination of multiscale experimental approaches, machine-learning-assisted statistical analysis, and experiment-informed mathematical modeling. Our results suggest that the degree of particle detachment is positively correlated with the charging rate and that smaller particles exhibit a higher degree of uncertainty in their detachment from the carbon/binder matrix. We further explore the feasibility and limitation of utilizing the reconstructed electron density as a proxy for the state-of-charge. Our findings highlight the importance of precisely quantifying the evolving nature of the battery electrode’s microstructure with statistical confidence, which is a key to maximize the utility of active particles towards higher battery capacity.

25 ENERGY STORAGE↗

Onboard early detection and mitigation of lithium plating in fast-charging batteries

Fast-charging is considered as one of the most desired features needed for lithium-ion batteries to accelerate the mainstream adoption of electric vehicles. However, current battery charging protocols mainly consist of conservative rate steps to avoid potential hazardous lithium plating and its associated parasitic reactions. A highly sensitive onboard detection method could enable battery fast-charging without reaching the lithium plating regime. Here, we demonstrate a novel differential pressure sensing method to precisely detect the lithium plating event. By measuring the real-time change of cell pressure per unit of charge (dP/dQ) and comparing it with the threshold defined by the maximum of dP/dQ during lithium-ion intercalation into the negative electrode, the onset of lithium plating before its extensive growth can be detected with high precision. In addition, we show that by integrating this differential pressure sensing into the battery management system (BMS), a dynamic self-regulated charging protocol can be realized to effectively extinguish the lithium plating triggered by low temperature (0 °C) while the conventional static charging protocol leads to catastrophic lithium plating at the same condition. We propose that differential pressure sensing could serve as an early nondestructive diagnosis method to guide the development of fast-charging battery technologies.

25 ENERGY STORAGE↗

Electric vehicle batteries alone could satisfy short-term grid storage demand by as early as 2030

The energy transition will require a rapid deployment of renewable energy (RE) and electric vehicles (EVs) where other transit modes are unavailable. EV batteries could complement RE generation by providing short-term grid services. However, estimating the market opportunity requires an understanding of many socio-technical parameters and constraints. We quantify the global EV battery capacity available for grid storage using an integrated model incorporating future EV battery deployment, battery degradation, and market participation. We include both in-use and end-of-vehicle-life use phases and find a technical capacity of 32–62 terawatt-hours by 2050. Low participation rates of 12%–43% are needed to provide short-term grid storage demand globally. Participation rates fall below 10% if half of EV batteries at end-of-vehicle-life are used as stationary storage. Short-term grid storage demand could be met as early as 2030 across most regions. Our estimates are generally conservative and offer a lower bound of future opportunities.

25 ENERGY STORAGE↗

Lithium inventory tracking as a non-destructive battery evaluation and monitoring method

Tracking the active lithium (Li) inventory in an electrode shows the true state of a Li battery, akin to a fuel gauge for an engine. However, non-destructive Li inventory tracking is currently unavailable. Here, in this work, we used the theoretical capacity of a transition metal oxide to convert capacity into a Li inventory analysis. The Li inventory in electrodes was tracked reliably to show how battery formulations and test methods affect performance. Contrary to capacity, Li inventory tracking reveals stoichiometric variations near the electrode–electrolyte interface. Verifiable results rationalized differences in measurements, clarifying and reducing interferences from cell formulations and experimental manipulations. By tracing four variables from formation to end-of-life, we characterize electrode and cell performance with a thermodynamic framework. Accurate rationalization of subtle differences in Li inventory utilization promises precise battery engineering, evaluation, failure analysis and risk mitigation. The method could be applicable from cell design optimization and fabrication to battery management, improving battery performance and reliability.

25 ENERGY STORAGE↗

Superionic conducting vacancy-rich β-Li 3 N electrolyte for stable cycling of all-solid-state lithium metal batteries

The advancement of all-solid-state lithium metal batteries requires breakthroughs in solid-state electrolytes (SSEs) for the suppression of lithium dendrite growth at high current densities and high capacities (>3 mAh cm -2 ) and innovation of SSEs in terms of crystal structure, ionic conductivity and rigidness. Here we report a superionic conducting, highly lithium-compatible and air-stable vacancy-rich β-Li 3 N SSE. This vacancy-rich β-Li 3 N SSE shows a high ionic conductivity of 2.14 × 10 -3 S cm -1 at 25 °C and surpasses almost all the reported nitride-based SSEs. A Li- and N-vacancy-mediated fast lithium-ion migration mechanism is unravelled regarding vacancy-triggered reduced activation energy and increased mobile lithium-ion population. All-solid-state lithium symmetric cells using vacancy-rich β-Li 3 N achieve breakthroughs in high critical current densities up to 45 mA cm -2 and high capacities up to 7.5 mAh cm -2 , and ultra-stable lithium stripping and plating processes over 2,000 cycles. The high lithium compatibility mechanism of vacancy-rich β-Li 3 N is unveiled as intrinsic stability to lithium metal. In addition, β-Li 3 N possesses excellent air stability through the formation of protection surfaces. All-solid-state lithium metal batteries using the vacancy-rich β-Li 3 N as SSE interlayers and lithium cobalt oxide (LCO) and Ni-rich LiNi 0.83 Co 0.11 Mn 0.06 O 2 (NCM83) cathodes exhibit excellent battery performance. Extremely stable cycling performance is demonstrated with high capacity retentions of 82.05% with 95.2 mAh g -1 over 5,000 cycles at 1.0 C for LCO and 92.5% with 153.6 mAh g -1 over 3,500 cycles at 1.0 C for NCM83. Utilizing the vacancy-rich β-Li 3 N SSE and NCM83 cathodes, the all-solid-state lithium metal batteries successfully accomplished mild rapid charge and discharge rates up to 5.0 C, retaining 60.47% of the capacity. Notably, these batteries exhibited a high areal capacity, registering approximately 5.0 mAh cm -2 for the compact pellet-type cells and around 2.2 mAh cm -2 for the all-solid-state lithium metal pouch cells.

25 ENERGY STORAGE↗

A Facile Approach to High Precision Detection of Cell-to-Cell Variation for Li-ion Batteries

Abstract Over the past decade, it has been repeatedly demonstrated that homogeneity in electrochemical performance of lithium-ion cells plays a major role in determining the life and safety of lithium-ion battery modules or packs. Generally, the homogeneity of a battery pack is evaluated by characterizing the cells individually in terms of capacity, mass, impedance. Particularly, high quality electrochemical data heavily relies on the availability of high precision current source to minimize the discrepancy induced by the channel-to-channel variation. Here, a facile and precise measurement method is reported for screening cell-to-cell variations, in which voltage is the only indicator parameter independent of high precision current source. In detail, by connecting the cells in series (CiS), the measurement error of electrochemical data caused by stability and discrepancy of current sources among different charge/discharge equipment can be effectively avoided. The findings of this work showed that the cell-to-cell variations can be simply and sensitively detected with CiS configuration. For example, the relative standard deviation, which is the evaluation criterion of battery homogeneity, was 2.14% based on CiS while it was 0.43% based on individual measurements. The simple and precise CiS measurement is promising for evaluation of cell quality or module integration quality. In addition, this work can also provide a solid foundation for the development of detection algorithms for battery management systems to rapidly monitor battery homogeneity.

25 ENERGY STORAGE↗

All-temperature zinc batteries with high-entropy aqueous electrolyte

Electrification of transportation and rising demand for grid energy storage continue to build momentum around batteries across the globe. However, the supply chain of Li-ion batteries is exposed to the increasing challenges of resourcing essential and scarce materials. Therefore, incentives to develop more sustainable battery chemistries are growing. Here, in this paper, we show an aqueous ZnCl 2 electrolyte with introduced LiCl as supporting salt. Once the electrolyte is optimized to Li 2 ZnCl 4 ∙9H 2 O, the assembled Zn–air battery can sustain stable cycling over the course of 800 hours at a current density of 0.4 mA cm -2 between -60 °C and +80 °C, with 100% Coulombic efficiency for Zn stripping/plating. Even at -60 °C, >80% of room-temperature power density can be retained. Advanced characterization and theoretical calculations reveal a high-entropy solvation structure that is responsible for the excellent performance. The strong acidity allows ZnCl 2 to accept donated Cl - ions to form ZnCl 4 2- anions, while water molecules remain within the free solvent network at low salt concentration or coordinate with Li ions. Our work suggests an effective strategy for the rational design of electrolytes that could enable next-generation Zn batteries.

25 ENERGY STORAGE↗

Directly Embedded Ni3S2/Co9S8@S-Doped Carbon Nanofiber Networks as a Free-Standing Anode for Lithium-Ion Batteries

Transition metal sulfides as electrode materials for lithium-ion batteries have attracted significant research attention due to their high theoretical capacity, excellent redox reversibility, and earth abundance. However, this material family still suffers from poor conductivity and experiences huge volume changes. Here, we demonstrate a facile and scalable electrospinning method to prepare Ni3S2 and Co9S8 nanoparticles embedded in sulfur doped carbon nanofiber networks as a free-standing anode material for lithium ion batteries. Similar to literature findings, the coupling of two different metal sulfides indeed synergistically promoted the electrochemical performance. Embedding them within individual carbon nanofibers not only enhances the intrinsic conductivity, but also provides a highly stable structure, which results in excellent battery performance. Furthermore, the individual carbon nanofibers intertwine with each other to form a free-standing 3D nanofiber network which acts as a freeway network for fast electron transfer and the pores between fibers allow easy penetration of the electrolyte, namely easy lithium ion access to active nanoparticles. When directly applied as the anode in lithium ion batteries, the free-standing nanofiber mat bypassed all slurry making steps and showed excellent cycling stability with a high specific capacity of 528 mA h g-1 after 200 cycles at a current density of 300 mA g-1. Good rate capability was also obtained. Additionally, the charge storage process analysis indicated that the pseudocapacitive behavior of the material is attributed to its good performance. This work introduces a facile strategy to simultaneously and in situ generate Co9S8 and Ni3S2 nanoparticles within a S-doped carbon fiber matrix via facile electrospinning followed by a one-step heating procedure. It is demonstrated that the free-standing transition bimetallic sulfide nanofibers prepared are very promising for light and small battery applications.

ADVANCED PROPULSION SYSTEMS,ENERGY STORAGE↗

Effect of externally applied pressure on rechargeable alkaline zinc batteries at limited depth of discharge

Rechargeable alkaline zinc batteries (AZBs) are being actively researched for grid-scale energy storage due to their safety, low toxicity, abundance, low cost, and ease-of-production. However, numerous studies on alkaline Zn–MnO 2 batteries have shown that issues such as heterogeneous Zn deposition, passivation, dendrite formation, hydrogen evolution, and formation of chemically irreversible byproducts on the electrode surfaces still limit their rechargeability. Several mitigating strategies have been proposed to improve the rechargeability of alkaline Zn–MnO 2 batteries, but the effect of pressure on electrochemical behavior has not been systematically investigated. In this paper, we demonstrate that an externally applied pressure at 20% MnO 2 depth-of-discharge (DOD MnO 2 ) has a profound effect on impedance, electrochemical cycling behavior, and materials morphology of alkaline Zn–MnO 2 batteries. Better electrochemical performance and improved morphology were achieved at 2.12 MPa pressure compared to 0.05 MPa pressure. Moreover, we examined the effect of externally applied pressure from 0 to 5.05 MPa before cycling and found that charge transfer resistance decreases significantly with pressure. Furthermore, we reported stable electrochemical cycling of MnO 2 ‖MnO 2 symmetric cells for 500 hours at 20% DOD under 2.12 MPa pressure. In conclusion, our efforts in understanding the effect of pressure could help design high performance and durable rechargeable alkaline Zn–MnO 2 batteries for grid-scale energy storage.

Rechargeable alkaline batteries↗