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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 19 records

A comparison of battery testing protocols: Those used by the U.S. advanced battery consortium and those used in China

Two testing protocols, QC/T 743 and those used by the U.S. Advanced Battery Consortium (USABC), were compared using cells based on LiFePO4/graphite chemistry. Differences in the protocols directly affected the data and the performance decline mechanisms deduced from the data. In all cases, the rate of capacity fade was linear with time. Overall, the testing protocols produced very similar data when the testing conditions and metrics used to define performance were similar. The choice of depth of discharge and pulse width had a direct effect on the apparent rate of resistance increased and estimated cell life. At greater percent depth of discharge (%DOD) and pulse width, the estimated life was shorter that at lower %DOD and shorter pulse width. This indicates that cells which were at the end of life based on the USABC protocol were not at end of life based on the QC/T 743 protocol by a large margin. (C) 2016 ELSEVIER B.V. All rights reserved.

battery testing↗

Beyond conventional batteries: a review on semi-solid and redox targeting flow batteries-LiFePO{sub 4} as a case study.

Clean and sustainable energy is becoming increasingly crucial to tackle the current energy crisis. However, the intermittent nature of renewable energy sources presents a challenge for their effective implementation. Redox flow batteries (RFBs) have emerged as a promising solution to this problem, as they can help enhance the stability of grid networks and promote the use of renewable energy sources. RFBs are highly modular and scalable systems that can be customized to meet the power and energy requirements of different renewable energy plants. Moreover, they offer several advantages over conventional battery technologies, including cost and safety concerns. However, conventional RFBs have limited energy densities due to the low solubility of their active species in electrolyte. To overcome this limitation, semi-solid (SSRFBs) and redox targeting (RTFBs) flow batteries have been proposed. These systems feature high concentrations of active species and impressive energy densities, making them highly attractive for renewable energy applications. LiFePO4 (LFP) is a highly promising active material for semi-solid and targeting flow batteries. One of the key advantages of LFP is its low raw materials cost, as it is composed of Earth-abundant elements such as iron and phosphorus. This makes it an attractive option for large-scale battery production. The recent developments in SSRFBs and RTFBs using LFP as catholyte hold great promise for the future of sustainable energy storage. The combination of LFP's low cost, safety, durability, and high energy density with the modularity and scalability of flow battery systems make for a compelling solution to the challenges of intermittent renewable energy sources. Ongoing research and development in this area will likely yield even further improvements in the performance and efficiency of LFP-based flow batteries, opening exciting new possibilities for sustainable energy storage.

El Halya, Nabil↗

Long term stability of Li-S batteries using high concentration lithium nitrate electrolytes

The lithium-sulfur (Li-S) battery is a very promising candidate for the next generation of energy storage systems required for electrical vehicles and grid energy storage applications due to its very high theoretical specific energy (2500 W h kg(-1)). However, low Coulombic efficiency (CE) during repeated Li metal plating/stripping has severely limited the practical application of rechargeable Li-S batteries. In this work, a new electrolyte system based on a high concentration of LiNO3 in diglyme (G2) solvent is developed which enables an exceptionally high CE for Li metal plating/stripping and thus high stability of the Li anode in the sulfur-containing electrolyte. The tailoring of electrolyte properties for the Li anode has proven to be a highly successful strategy for improving the capacity retention and cycle life of Li-S batteries. This electrolyte provides a CE of greater than 99% for over 200 cycles of Li plating/stripping. In contrast, the Li anode cycles for less than 35 cycles (with a high CE) in the state-of-the-art 1 M LiTFSI + 0.3 M LiNO3 in 1,3-dioxolane: 1,2-dimethoxyethane (DOL:DME) electrolyte under the same conditions. The stable Li anode enabled by the new electrolyte may accelerate the applications of high energy density Li-S batteries in both electrical vehicles and large-scale grid energy storage markets.

Coulombic efficiency↗

Rechargeable Aluminum-Ion Batteries Based on an Open-Tunnel Framework

Rechargeable batteries based on an abundant metal such as aluminum with a three-electron transfer per atom are promising for large-scale electrochemical energy storage. Aluminum can be handled in air, thus offering superior safety, easy fabrication, and low cost. But, the development of Al-ion batteries has been challenging due to the difficulties in identifying suitable cathode materials. This study presents the use of a highly open framework Mo 2.5 + y VO 9 + z as a cathode for Al-ion batteries. The open-tunnel oxide allows a facile diffusion of the guest species and provides sufficient redox centers to help redistribute the charge within the local host lattice during the multivalent-ion insertion, thus leading to good rate capability with a specific capacity among the highest reported in the literature for Al-based batteries. Our study also presents the use of Mo 2.5 + y VO 9 + z as a model host to develop a novel ultrafast technique for chemical insertion of Al ions into host structures. The microwave-assisted method employing diethylene glycol and aluminum diacetate (Al(OH)(C 2 H 3 O 2 ) 2 ) can be performed in air in as little as 30 min, which is far superior to the traditional chemical insertion techniques involving moisture-sensitive organometallic reagents. The Al-inserted Al x Mo 2.5 + y VO 9 + z obtained by the microwave-assisted chemical insertion can be used in Al-based rechargeable batteries.

25 ENERGY STORAGE↗

Effects of Imide–Orthoborate Dual-Salt Mixtures in Organic Carbonate Electrolytes on the Stability of Lithium Metal Batteries

The effects of lithium imide and lithium orthoborate dual-salt electrolytes of different salt chemistries in carbonate solvents on the cycling stability of Li metal batteries were systematically and comparatively investigated. Two imide salts (LiTFSI and LiFSI) and two orthoborate salts (LiBOB and LiDFOB) were chosen for this study and compared with the conventional LiPF6 salt. The cycling stability of the Li metal cells with the electrolytes follows the order from good to poor as LiTFSI-LiBOB > LiTFSI-LiDFOB > LiPF6 > LiFSI-LiBOB > LiFSI-LiDFOB, indicating that LiTFSI behaves better than LiFSI and LiBOB over LiDFOB in these four dual-salt mixtures. The LiTFSI-LiBOB can effectively protect the Al substrate and form a more robust surface film on Li metal anode, while the LiFSI-LiBOB results in serious corrosion to the stainless steel cell case and a thicker and looser surface film on Li anode. Computational calculations indicate that the chemical and electrochemical stabilities also follow the order of LiTFSI-LiBOB > LiTFSI-LiDFOB > LiFSI-LiBOB > LiFSI-LiDFOB. The key findings of this work emphasize that the salt chemistry is critically important for enhancing the interfacial stability of Li metal anode and should be carefully manipulated in the development of high performance Li metal batteries.

Li metal batteries, dual-salt electrolyte, solid e↗

A lithium–oxygen battery with a long cycle life in an air-like atmosphere [Lithium-oxygen batteries with long cycle life in a realistic air atmosphere]

Lithium-air batteries are considered to be a potential alternative to lithium-ion batteries for transportation applications, owing to their high theoretical specific energy. So far, however, such systems have been largely restricted to pure oxygen environments (lithium oxygen batteries) and have a limited cycle life owing to side reactions involving the cathode, anode and electrolyte. In the presence of nitrogen, carbon dioxide and water vapour, these side reactions can become even more complex. Moreover, because of the need to store oxygen, the volumetric energy densities of lithium-oxygen systems may be too small for practical applications. Here we report a system comprising a lithium carbonate-based protected anode, a molybdenum disulfide cathode and an ionic liquid/di methyl sulfoxide electrolyte that operates as a lithium-air battery in a simulated air atmosphere with a long cycle life of up to 700 cycles. We perform computational studies to provide insight into the operation of the system in this environment. Furthermore this demonstration of a lithium-oxygen battery with a long cycle life in an air-like atmosphere is an important step towards the development of this field beyond lithium-ion technology, with a possibility to obtain much higher specific energy densities than for conventional lithium ion batteries.

25 ENERGY STORAGE↗

Development and validation of chemistry agnostic flow battery cost performance model and application to nonaqueous electrolyte systems: Chemistry agnostic flow battery cost performance model

A chemistry agnostic cost performance model is described for a nonaqueous flow battery. The model predicts flow battery performance by estimating the active reaction zone thickness at each electrode as a function of current density, state of charge, and flow rate using measured data for electrode kinetics, electrolyte conductivity, and electrode-specific surface area. Validation of the model is conducted using a 4kW stack data at various current densities and flow rates. This model is used to estimate the performance of a nonaqueous flow battery with electrode and electrolyte properties used from the literature. The optimized cost for this system is estimated for various power and energy levels using component costs provided by vendors. The model allows optimization of design parameters such as electrode thickness, area, flow path design, and operating parameters such as power density, flow rate, and operating SOC range for various application duty cycles. A parametric analysis is done to identify components and electrode/electrolyte properties with the highest impact on system cost for various application durations. A pathway to 100$kWh -1 for the storage system is identified.

25 ENERGY STORAGE↗

Failure Mechanism of Fast-Charged Lithium Metal Batteries in Liquid Electrolyte

In recent years, lithium anode has re-attracted broad interest because of the necessity of employing lithium metal in the next-generation battery technologies such as lithium sulfur (Li-S) and lithium oxygen (Li-O2) batteries. Fast capacity degradation and safety issue associated with rechargeable lithium metal batteries have been reported, although the fundamental understanding on the failure mechanism of lithium metal at high charge rate is still under debate due to the complicated interfacial chemistry between lithium metal and electrolyte. Herein, we demonstrate that, at high current density, the quick growth of porous solid electrolyte interphase towards bulk lithium, instead of towards the separator, dramatically builds up the cell impedance that directly leads to the cell failure. Understanding the lithium metal failure mechanism is very critical to gauge the various approaches used to address the stability and safety issues associated with lithium metal anode. Otherwise, all cells will fail quickly at high rates before the observation of any positive effects that might be brought from adopting the new strategies to protect lithium.

Environmental Molecular Sciences Laboratory↗

Lithium-ion battery physics and statistics-based state of health model

A pseudo-2d model using COMSOL Multiphysics® software is developed to simulate performance and performance degradation of Li-ion batteries consisting of layered and olivine cathodes with graphite anode when subjected to peak shaving grid service. Multiple degradation pathways are considered, including solid electrolyte interphase (SEI) formation and breakdown at the anode, cathode dissolution and its synergistic effect on SEI formation at the anode. The model is validated by simulating commercial cylindrical cell performance. A global model is developed to simulate performance across all chemistries, along with individual chemistry models using global model parameters as initial values. There is good agreement between these models for various optimization parameters such as SEI equilibrium potential, cathode dissolution exchange current density, solvent diffusivity in the SEI and SEI ionic conductivity. To circumvent time constraints related to the COMSOL model, a 0d global model is developed which fits data well and provides more clarity on differences in cathode dissolution exchange current density. Again, good agreement for various optimization parameters is obtained among the COMSOL global & individual chemistry models and the 0-d model. The lessons learned from the physics-based model is used to develop a top down statistics-based model using current, voltage and anode volumetric change per mole lithium intercalated, along with their interactions as degradation predictors. This model predicts out of sample degradation for multiple grid services and electric vehicle drive cycle with high accuracy and provides the pathway to develop an efficient battery management system combining machine learning and findings from physics-based computationally intensive algorithms.

Crawford, Aladsair J.↗