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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 379 records · Page 21

Development of cathode-electrolyte-interphase for safer lithium batteries

Accompanied by the adoption of aggressive cathodes to continuously improve batteries energy density, enhancing their safety is becoming increasingly urgent for the electric vehicle development. In-situ controllable formation of robust cathode-electrolyte interphase (CEI) with high inorganic content seems to be the most promising strategy to address the thermal runaway concerns. Moreover, the in-situ formation strategy via suitable electrolyte replacement or electrolyte additives is extremely simple yet effective, especially for industrial manufacture of batteries. Here, this paper briefly reviews recent advanced CEIs formed by conventional carbonate-based electrolytes, fluorinated electrolytes, concentrated electrolytes, and solid state electrolytes. The focus on the thermal stability of the cathodes after CEI modification, and at the same time conduct safety tests at the material, cell, and module levels for comprehensive evaluation are encouraged. The review will provide inspiration for future developments in battery safety and push forward the practical applications of newly developed high-energy density batteries.

25 ENERGY STORAGE↗

Proton-enabled biomimetic stabilization of small-molecule organic cathode in aqueous zinc-ion batteries

Small-molecule organic cathode materials offer flexible structural design features, high capacity and sustainable production. Nonetheless, the stability decrease due to the high solubility of the electrode materials especially under electrochemical cycling conditions limits their wide-range applications in energy storage technologies. Here we describe a nature-inspired strategy to address cathode stability via introduction of transient vinylogous amide hydrogen bond networks into the small-molecule organic electrode material hexaazatrianthranylene (HATA) embedded quinone (HATAQ). Thanks to the proton-enabled biomimetic mechanism, HATAQ exhibits unparalleled cycling stability, ultra-high capacity and rate capability in aqueous zinc-ion batteries, delivering 492 mA h g -1 at 50 mA g -1 and a reversible capacity of 199 mA h g -1 , corresponding to 99% retention at 20 A g -1 after 1000 cycles.

25 ENERGY STORAGE↗

From Copper to Basic Copper Carbonate: A Reversible Conversion Cathode in Aqueous Anion Batteries

Dual-ion batteries that use anions and cations as charge carriers represent a promising energy-storage technology. However, an uncharted area is to explore transition metals as electrodes to host carbonate in conversion reactions. Here we report the reversible conversion reaction from copper to Cu 2 CO 3 (OH) 2 , where the copper electrode comprising K 2 CO 3 and KOH solid is self-sufficient with anion-charge carriers. This electrode dissociates and associates K + ions during battery charge and discharge. The copper active mass and the anion-bearing cathode exhibit a reversible capacity of 664 mAh g –1 and 299 mAh g –1 , respectively, and relatively stable cycling in a saturated mixture electrolyte of K 2 CO 3 and KOH. Finally, the results open an avenue to use carbonate as a charge carrier for batteries to serve for the consumption and storage of CO 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

A High Energy–Density, Cobalt–Free, Low–Nickel LiNi 0.7 Mn 0.25 Al 0.05 O 2 Cathode with a High–Voltage Electrolyte for Lithium–Metal Batteries

Cobalt-free cathode materials have garnered increased attention for applications in next-generation batteries for electric vehicles, as cobalt is considered to have at a high supply chain risk. Here, the use of a localized saturated electrolyte (LSE) to enable stable cycling of a cobalt-free, low-nickel layered-oxide cathode LiNi 0.7 Mn 0.25 Al 0.05 O 2 (NMA-70) to higher voltages (4.6 V) in a lithium-metal battery is demonstrated. Compared to the baseline LP57 electrolyte, the LSE extends the cycle life from ≈100 cycles to ≈400 cycles before reaching 80% capacity retention. Visual indicators of cell degradation, such as product deposition, are observed on electrodes cycled in LP57. It is shown that cycling NMA-70 in LSE reduces the overall active material loss and overpotential growth during extended cycling. This is attributed to the formation of a beneficial fluorinated interphase layer, a lower degree of rock-salt phase formation, and a reduction in the gas evolution from the cathode surface. The decrease in gas evolution from the cathode cycled in LSE reflects a lower degree of electrolyte reactivity and an overall improvement in the safety characteristics of the cell. Furthermore, this study highlights the importance of a stable electrolyte to enable the high-voltage cycling of alternative, lower nickel, and cobalt-free cathodes.

25 ENERGY STORAGE↗

Cathode materials for lithium ion batteries

A process of forming a coated cathode active material include preparing a cathode material precursor by co-precipitation; coating the cathode material precursor with an electrochemically inert coating material precursor by precipitation to form a coated cathode material precursor; lithiating the coated cathode material precursor with a lithium source material to form a lithiated coated cathode material precursor; and sintering the lithiated coated cathode material precursor to form a cathode active material coated with an electrochemically inert material.

Wu, Huiming↗

High-entropy Li-rich layered oxide cathode for Li-ion batteries

High-entropy oxides (HEOs) are emerging as promising cathode materials for Li-ion batteries (LIBs) due to their stable solid-state phase and compositional flexibility. Herein, we investigate the structural and electrochemical properties of a novel non-equimolar high-entropy cathode material, termed high-entropy Li-rich layered oxide (HE-LLO, Li 1.15 Na 0.05 Ni 0.19 Mn 0.56 Fe 0.02 Mg 0.02 Al 0.02 O 1.97 F 0.03 ), in comparison to a pristine Li-rich layered oxide (PR-LLO, Li1.2Ni0.2Mn0.6O2). The incorporation of multiple cations (Na + , Al 3+ , Mg 2+ , Fe 3+ ) and anion (F - ) into HE-LLO introduces compositional diversity, enhancing structural stability through the entropy stabilization effect. Theoretical calculations confirm a significantly higher configurational entropy in HE-LLO compared to PRLLO, supporting its high-entropy nature. Electrochemical evaluations demonstrate that HE-LLO exhibits considerable capacity retention, preserving 76.8 % of its discharge capacity at 0.5C after 200 cycles, compared to only 36.2 % for PR-LLO. Even under high-temperature conditions, HE-LLO outperformed PR-LLO, maintaining 76.1 % of its discharge capacity after 100 cycles at 5C, while PR-LLO retained only 12.4 %. These enhancements are attributed to the improved phase reversibility and higher Li + ion diffusion coefficients of HE-LLO, validated by ex-situ characterizations using a synchrotron X-ray technique, along with density functional theory (DFT) calculations. In conclusion, these findings highlight the promise of non-equimolar HEOs as a novel design strategy for highperformance cathode materials.

25 ENERGY STORAGE↗

Whole-Voltage-Range Solid-Solution Reaction in Layered Oxide Cathode of Sodium-Ion Batteries

Layered manganese-based oxides (LMOs) are promising cathode materials for sodium-ion batteries (SIBs) due to their versatile structures. However, the Jahn–Teller effect of Mn 3+ induces severe distortion of MnO 6 octahedra, and the resultant low symmetry is responsible for the gliding of MnO 2 layers and then inferior multiple-phase transitions upon Na + extraction/insertion. Here, hexagonal P2-Na 0.643 Li 0.078 Mn 0.827 Ti 0.095 O 2 is synthesized through the incorporation of Li and Ti into the distorted orthorhombic P'2-Na 0.67 MnO 2 to function as a phase-transition-free oxide cathode. Further, it is revealed that Li in both the transition-metal and Na layers enhances the covalency of Mn–O bonds and allows degeneracy of Mn 3d e g orbitals to favor the formation of hexagonal phase, and the high strength of Ti–O bonds reduces the electrostatic interaction between Na and O for suppressed Na + /vacancy rearrangements. These collectively lead to a whole-voltage-range solid-solution reaction between 1.8 and 4.3 V with a small volume variation of 1.49%. This rewards its excellent cycling stability (capacity retention of 90% after 500 cycles) and rate capability (89 mAh g -1 at 2000 mA g -1 ).

25 ENERGY STORAGE↗

Cathode additives for lithium-ion batteries

In some implementations, a cathode is formed by (1) providing a cathode additive including (a) a matrix including a lithium compound, and (b) metal nanostructures embedded in the matrix; and (2) combining the cathode additive with a cathode active material to form a mixture. In other implementations, a cathode is formed by (1) providing a cathode additive including a compound of lithium and at least one non-metal or metalloid; and (2) combining the cathode additive with a cathode active material to form a mixture.

25 ENERGY STORAGE↗

Copper-containing layered oxide cathodes for sodium-ion batteries

Layered transition metal oxides are among the most promising cathode materials for sodium-ion batteries due to their high theoretical capacity, structural tunability, and cost-effectiveness. However, conventional Ni- and Co-based layered oxides are hindered by high raw material costs, limited elemental abundance, and phase instability during electrochemical cycling. Recently, copper has emerged as an attractive alternative transition metal, offering significant advantages in terms of redox activity, structural stabilization, voltage regulation, and rate performance. Unlike Ni and Co, Cu can facilitate unique redox mechanisms and enable more sustainable material design. This review systematically summarizes recent progress on Cu-containing layered sodium oxides, with emphasis on their structural characteristics, electrochemical behavior, and the critical roles that Cu plays within the host lattice. The insights provided herein aim to highlight the potential of Cu-substituted or Cu-containing layered oxides as a viable pathway toward high-performance and resource-accessible SIB cathodes for future energy storage applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Origins of Irreversibility in Layered NaNi x Fe y Mn z O 2 Cathode Materials for Sodium Ion Batteries

Layered NaNi x Fe y Mn z O 2 cathode (NFM) is of great interest in sodium ion batteries due to its high theoretical capacity and utilization of abundant, low-cost, environmentally-friendly raw materials. Nevertheless, there remains insufficient understanding on the concurrent local environment evolution in each transition metal (TM) that largely influences the reversibility of the cathode materials upon cycling. In this work, we investigate the reversibility of TM ions in layered NFMs with varying Fe contents and potential windows. Utilizing ex situ synchrotron X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) of pre-cycled samples the valence and bonding evolution of the TMs are elucidated. It is found that Mn is electrochemically inactive as indicated by the insignificant change of Mn valence and Mn-O bonding distance. Fe is electrochemically inactive after the first five cycles. The Ni redox couple contributes most of the charge compensation for NFMs. Ni redox is quite reversible in the cathodes with less Fe contents. Furthermore, the Ni redox couple shows significant irreversibility with high Fe content of 0.8. The electrochemical reversibility of the NFM cathode becomes increasingly enhanced with the decrease of either Fe content or with lower upper charge cutoff potential.

25 ENERGY STORAGE↗

A Cobalt– and Manganese–Free High–Nickel Layered Oxide Cathode for Long–Life, Safer Lithium–Ion Batteries

High-nickel LiNi 1–x–y Mn x Co y O 2 and LiNi 1–x–y Co x Al y O 2 cathodes are receiving growing attention due to the burgeoning demands on high-energy-density lithium-ion batteries. The presence of both cobalt and manganese in them, however, triggers multiple issues, including high cost, high toxicity, rapid surface deterioration, and severe transition-metal dissolution. Herein, a Co- and Mn-free ultrahigh-nickel LiNi 0.93 Al 0.05 Ti 0.01 Mg 0.01 O 2 (NATM) cathode that exhibits 82% capacity retention over 800 deep cycles in full cells, outperforming two representative high-Ni cathodes LiNi 0.94 Co 0.06 O 2 (NC, 52%) and LiNi 0.90 Mn 0.05 Co 0.05 O 2 (NMC, 60%) is presented. It is demonstrated that a titanium-enriched surface along with aluminum and magnesium as the stabilizing ions in NATM not only ameliorates unwanted side reactions with the electrolyte and structural disintegrity, but also mitigates transition-metal dissolution and active lithium loss on the graphite anode. As a result, the graphite anode paired with NATM displays an ultrathin (≈8 nm), monolayer anode-electrolyte interphase architecture after extensive cycling. Furthermore, NATM displays considerably enhanced thermal stability with an elevated exothermic temperature (213 °C for NATM vs 180 and 190 °C for NC and NMC, respectively) and remarkably reduced heat release. This work sheds light on rational compositional design to adopt ultrahigh-Ni cathodes in lithium-based batteries with low cost, long service life, and improved thermal stability.

25 ENERGY STORAGE↗

Anomalous Redox Features Induced by Strong Covalency in Layered NaTi 1-y V y S 2 Cathodes for Na-Ion Batteries

The rising demand for energy density of cathodes means the need to raise the voltage or capacity of cathodes. Transition metal (TM) doping has been employed to enhance the electrochemical properties in multiple aspects. The redox voltage of doped cathodes usually falls in between the voltage of undoped layered cathodes. However, in this study, we found anomalous redox features in NaTi 1-y V y S 2 . The first discharge platform potential (2.4 V) is significantly higher than that of undoped NaTiS 2 and NaVS 2 (both around 2.2 V), and the energy density is raised by 15%. We speculate that the anomalous voltage is mainly attributed to the strong hybridization in the Ti-V-S system. Ti 3+ and V 3+ undergo charge transfer and form a more stable Ti (t 2g 0 e g 0 ) and V (t 2g 3 e g 0 ) electronic configuration. Our results indicate that higher voltage of cathode materials could be achieved by strong TM-ligand covalency, and this conclusion provides possible opportunities to explore high voltage materials for future layered cathodes.

36 MATERIALS SCIENCE↗

Pinned Electrode/Electrolyte Interphase and Its Formation Origin for Sulfurized Polyacrylonitrile Cathode in Stable Lithium Batteries

Sulfurized polyacrylonitrile (SPAN) represents one of the most promising directions for high-energy-density lithium (Li)-sulfur batteries. However, the practical application of Li||SPAN is currently limited by the insufficient chemical/electrochemical stability of electrode/electrolyte interphase (EEI). Here, a pinned EEI layer is designed for stabilizing a SPAN cathode by regulating the EEI formation mechanism in an advanced LiFSI/ether/fluorinated-ether electrolyte. Computational simulations and experimental investigations reveal that, benefiting from the nonsolvating nature, the fluorinated-ether can not only act as a protective shield to prevent the Li polysulfides dissolution but also, more importantly, endow a diffusion-controlled EEI formation process. It promotes the formation of a uniform, protective, and conductive EEI layer pinning into SPAN surface region, enabling the high loading Li||SPAN batteries with superior cycling stability, wide temperature performance, and high-rate capability. Finally, this design strategy opens an avenue for exploring advanced electrolytes for Li||SPAN batteries and guides the interface design for broad types of battery systems.

25 ENERGY STORAGE↗

Entropy-Stabilized Multication Fluorides as a Conversion-Type Cathode for Li-Ion Batteries–Impact of Element Selection

Metal fluorides (e.g., FeF 2 and FeF 3 ) have received attention as conversion-type cathode materials for Li-ion batteries due to their higher theoretical capacity compared to that of common intercalation materials. However, their practical use has been hindered by low round-trip efficiency, voltage hysteresis, and capacity fading. Cation substitution has been proposed to address these challenges, and recent advancements in battery performance involve the introduction of entropy stabilization in an attempt to facilitate reversible conversion reactions by increasing configurational entropy. Building on this concept, high entropy fluorides with five cations were synthesized by using a simple mechanochemical route. In order to examine the impact of element selection, Co 0.2 Cu 0.2 Ni 0.2 Zn 0.2 Fe 0.2 F 2 (HEF-Fe) was compared with Co 0.2 Cu 0.2 Ni 0.2 Zn 0.2 Mg 0.2 F 2 (HEF-Mg), replacing electrochemically inactive Mg with Fe as an active participant in the conversion reaction. Combining electrochemical measurements with first-principles calculations, high-resolution electron microscopy, and synchrotron X-ray analysis, HEFs’ battery performances and conversion reaction mechanisms were investigated in detail. The results highlighted that replacement of Mg with Fe was beneficial, with enhanced capacity, rate capability, and surface stability. In addition, it was found that HEF-Fe showed similar cycle stability without an electrochemically inactive element. In conclusion, these findings provide valuable insights for the design of high entropy multielement fluorides for improved Li-ion battery performance.

25 ENERGY STORAGE↗

The Role of Metal Oxides in Li-S Batteries: A High-Areal-Capacity Sulfur Composite Cathode Investigation

Compared to lithium-ion batteries (LIB), lithium-sulfur (Li-S) batteries have low cost and high theoretical specific energy (2510 Wh/kg or about 10 times of the LIB). However, Li-S batteries have several challenges, including large volume expansion, poor utilization of the end products, sluggish kinetics of polysulfides, and crossover, so-called the "shuttle effect". To address these issues, we have introduced metal oxides to the Li-S electrode to develop a metal-oxide-sulfur composite electrode. We aim to use metal oxides to assist the Li-S formation (dissociation) during discharge (charge) cycles. We elect to focus on LIB-based metal oxides to ensure that the added material can contribute storage capacity to the battery. Our cathodes are fabricated by both the conventional slurry casting and air-controlled electrospray. LIB electrode materials, such as Li(Ni 0.6 Mn 0.6 Co 0.2 )O 2 , LiMn 2 O 4 , Li 2 TiO 3 , etc, were incorporated with the sulfur-carbon composite and their charge-discharge performances are compared. We found that the presence of metal oxides increased sulfur utilization with stable cycling performance, even in cells with high areal capacities. To unveil the interactions between lithium metal oxides and sulfur, the cathodes were analyzed by various characterization techniques, including scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and electrochemistry. The analysis of the role of the oxides will be presented along with the reaction mechanism.

25 ENERGY STORAGE↗

Whole-Voltage-Range Oxygen Redox in P2-Layered Cathode Materials for Sodium-Ion Batteries

Oxygen-redox of layer-structured metal-oxide cathodes has drawn great attention as an effective approach to break through the bottleneck of their capacity limit. However, reversible oxygen-redox can only be obtained in the high-voltage region (usually over 3.5 V) in current metal-oxide cathodes. Here, we realize reversible oxygen-redox in a wide voltage range of 1.5-4.5 V in a P2-layered Na 0.7 Mg 0.2 [Fe 0.2 Mn 0.6 $\square$0.2]O 2 cathode material, where intrinsic vacancies are located in transition-metal (TM) sites and Mg-ions are located in Na sites. Mg-ions in the Na layer serve as "pillars" to stabilize the layered structure during electrochemical cycling, especially in the high-voltage region. Intrinsic vacancies in the TM layer create the local configurations of "$\square$-O-$\square$", "Na-O-$\square$" and "Mg-O-$\square$" to trigger oxygen-redox in the whole voltage range of charge-discharge. Additionally, time-resolved techniques demonstrate that the P2 phase is well maintained in a wide potential window range of 1.5-4.5 V even at 10 C. It is revealed that charge compensation from Mn- and O-ions contributes to the whole voltage range of 1.5-4.5 V, while the redox of Fe-ions only contributes to the high-voltage region of 3.0-4.5 V. The orphaned electrons in the nonbonding 2p orbitals of O that point toward TM-vacancy sites are responsible for reversible oxygen-redox, and Mg-ions in Na sites suppress oxygen release effectively.

25 ENERGY STORAGE↗