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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 109 records · Page 6
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DOE OSTI2021

Selective dopant segregation modulates mesoscale reaction kinetics in layered transition metal oxide

Incorporation of foreign elements into the cathode material is broadly adopted by both academia and industry to improve the battery performance. The lack of an in-depth understanding for the underlying mechanism, however, makes it a largely try-and-error process with unsatisfactory efficiency and effectiveness. This is particularly true for the electrochemical reaction kinetics that is heterogeneous over a broad range of length scales and is determined collectively by the cathode’s electronic structure, lattice configuration, and micro-morphology. In this work, we unveiled a facet-dependent dopant segregation effect in Zr-modified single-crystal LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode. By forming kinetically favored corners on the cathode particles, the presence of a trace amount of Zr critically modulates the mesoscale reaction kinetics. Our findings suggest that a delicately controlled dopant distribution is a viable strategy for designing the next-generation battery cathode with superior structural and chemical robustness.

36 MATERIALS SCIENCE↗
DOE OSTI2026

State-of-Charge Investigation of Lithium Manganese Dioxide Primary Batteries Utilizing X-ray Computed Tomography

Lithium primary batteries (LPBs) represent a class of energy storage devices, uniquely suited for mission-critical applications including emergency backup power, aerospace and defense electronics, implantable medical devices, and remote sensing. Despite their technological maturity and distinct advantages over rechargeable lithium-ion batteries (i.e., superior shelf life and operational simplicity), state-of-charge (SoC) estimation in these batteries remains a persistent challenge due to the lack of a reliable, quantifiable diagnostic technique. In this work, we investigate X-ray computed tomography (X-CT) as a transformative and accurate SoC estimation technique for LPBs. Results gained through X-CT measurements reveal systematic, quantifiable structural changes in cathode morphology and geometry during discharge, establishing a direct structural basis for SoC estimation, with a maximum relative standard deviation of 2.3%. This work establishes a pathway toward operando, imaging-driven SoC diagnostics that can significantly enhance the reliability of SoC estimation in LPBs.

25 ENERGY STORAGE↗
DOE OSTI2020

Synergistic Effect of High Sulfur Loading Layered Cathode, Ceramic Separator and Gel Electrolyte

Lithium sulfur (Li-S) batteries are promising candidates for next-generation energy storage devices as they are capable of providing higher energy density and lower cost in comparison to the state of the art Li-ion batteries. To gain these characteristics, there are challenges such as polysulfide crossover, large volume changes during cycling, and deposition of insulating lithium sulfide that need to be alleviated. A popular approach to address these issues is to control the structure and properties of the carbon cathode in order to influence the transport of polysulfides, surface area for reaction, and lithium sulfide deposition. Ceramic separators on the other hand can drastically affect ion diffusion and overall battery performance. Safety concerns regarding the flammable liquid electrolyte can be reduced by deploying gel electrolyte. Towards this direction, we developed a layer-on-layer cathode structure with sulfur-impregnated activated carbon alternating with graphene layer, which was fabricated by Air-assisted electrospray. A much higher sulfur loading compared to slurry cast cathodes can be provided in this method. Combining the new cathode with gel electrolyte can offer higher safety of the battery and capacity retention. Ceramic separator would compensate the reduced ion conductivity of the gel electrolyte and the combination of these variables will be very promising in improvement of battery performance and safety.

25 ENERGY STORAGE↗
DOE OSTI2025

Designing Advanced Electrolytes for High-Voltage High-Capacity Disordered Rocksalt Cathodes

Lithium (Li)-excess transition metal oxide materials which crystallize in the cation-disordered rock salt (DRX) structure are promising cathodes for realizing low-cost, high-energy-density Li batteries. However, the state-of-the-art electrolytes for Li-ion batteries cannot meet the high-voltage stability requirement for high-voltage DRX cathodes, thus new electrolytes are urgently demanded. It has been reported that the solvation structures and properties of the electrolytes critically influence the performance and stability of the batteries. In this study, the structure–property relationships of various electrolytes with different solvent-to-diluent ratios are systematically investigated through a combination of theoretical calculations and experimental tests and analyses. This approach guides the development of electrolytes with unique solvation structures and characteristics, exhibiting high voltage stability, and enhancing the formation of stable electrode/electrolyte interphases. These electrolytes enable the realization of Li||Li 1.094 Mn 0.676 Ti 0.228 O 2 (LMTO) DRX cells with improved performance compared to the conventional electrolyte. Specifically, Li||LMTO cells with the optimized advanced controlled-solvation electrolyte deliver higher specific capacity and longer cycle life compared to cells with the conventional electrolyte. Additionally, the investigation into the structure–property relationship provides a foundational basis for designing advanced electrolytes, which are crucial for the stable cycling of emerging high-voltage cathodes.

25 ENERGY STORAGE↗
DOE OSTI2020

Probing the Thermal-Driven Structural and Chemical Degradation of Ni-Rich Layered Cathodes by Co/Mn Exchange

The intrinsic poor thermal stability of layered LiNi x Co y Mn 1-x-y O 2 (NCM) cathodes and the exothermic side reactions triggered by the associated oxygen release are the main safety threats for their large-scale implantation. In NCM family, it is widely accepted that Ni is the stability troublemaker, while Mn has long been considered as a structure stabilizer, whereas the role of Co remains elusive. Here, via Co/Mn exchange in Ni-rich LiNi 0.83 Co 0.11 Mn 0.06 O 2 cathode, we demonstrate that, the chemical and structural stability of the deep delithiated NCM cathodes are significantly affected by Co, rather than the widely reported Mn. Operando synchrotron X-ray characterization coupling with in situ mass spectrometry reveal that the Co 4+ reduces prior to the reduction of Ni 4+ , and could thus prolong the Ni migration by occupying the tetrahedra sites, and hence postpone the oxygen release and thermal failure. In contrast, the Mn itself is stable, but barely stabilizes the Ni 4+ . Our results highlight the importance of evaluating the intrinsic role of compositional tuning on Ni-rich/Co-free layered oxide cathode materials to guarantee the safe operation of high-energy Li-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2025

Atomic Structural Features of Stacking Faults and Domain Connections in the Li- and Mn-Rich Cathode

Li- and Mn-rich layered oxides (LMRs), a class of earth-abundant materials for rechargeable Li-ion battery cathodes, crystallize into layered structures of two different symmetries: C2/m represented by Li 2 MnO 3 and R$\overline{3}$m represented by LiMn 0.5 Ni 0.5 O 2 . Fundamental questions about how the C2/m and R$\overline{3}$m domains spatially correlate within the same oxide grain and how the C2/m stacking faults arrange themselves when this happens still remain. Here, by using integrated differential phase contrast imaging in scanning transmission electron microscopy (STEM-iDPC), we probe the structural and compositional details of a prototypical, cobalt-free LMR material, 0.3Li 2 MnO 3 •0.7LiMn 0.5 Ni 0.5 O 2 (Li 1.13 Mn 0.57 Ni 0.3 O 2 ). The connection between the C2/m and R$\overline{3}$m domains is found to be abrupt, facilitated by the small lattice mismatch between the two structures. Stacking faults in the C2/m domains feature atomic plane shifting that accommodates stacking sequence changes, which explains why the stacking faults form in a random manner. Furthermore, a local disordering mechanism was identified to correlate with the C2/m stacking faults. Chemically, it is found that Ni coexists with Mn at the transition metal sites within the nominal Li 2 MnO 3 domain. As a result, this study demonstrates that STEM-iDPC is a very useful tool for capturing all the elements in a single image, revealing atomic details on domain connections and stacking faults in the LMRs.

Li-rich and Mn-rich oxides↗
DOE OSTI2023

Synthesis, structural and electrochemical properties of V4O9 cathode for lithium batteries

Single-phase three-dimensional vanadium oxide (V 4 O 9 ) was synthesized by reduction of V 2 O 5 using a gas stream of ammonia/argon (NH 3 /Ar). The as-synthesized oxide, prepared by this simple gas reduction method was subsequently electrochemically transformed into a disordered rock salt type-“Li3.7V4O9” phase while cycling over the voltage window 3.5 to 1.8 V versus Li. The Li-deficient phase delivers an initial reversible capacity of ∼260 mAhg −1 at an average voltage of 2.5 V vs. Li + /Li 0 . Further cycling to 50 cycles yields a steady 225 mAhg −1 . Ex situ X-ray diffraction studies confirmed that (de) intercalation phenomena follows a solid-solution electrochemical reaction mechanism. As demonstrated, the reversibility and capacity utilization of this V 4 O 9 is found to be superior to battery grade, micron-sized V 2 O 5 cathodes in lithium cells.

25 ENERGY STORAGE↗
DOE OSTI2023

xLi2MnO3 (1-x)LiMeO2 and Li4Ti5O12 Cell Chemistry for Behind-the-Meter Storage Applications

Li- and Mn-rich layered oxide material (xLi2MnO3 (1-x)LiMeO2, Me = Ni, Mn, and etc., LMR-NM) is paired with Li4Ti5O12 (LTO) in a full cell and evaluated for the Behind-the-Meter Storage (BTMS) applications. The LMR-NM/LTO full cell shows very high capacities and excellent long-term cycle life. It delivers 192 mAh g-1 after 500 cycles at C/2 and 45 degrees C with a capacity retention of 75% and coulombic efficiency higher than 99.95%. It also has impressive rate capabilities. A capacity of 220 mAh g-1 is achieved at 2C which is 88 % of the initial capacity at C/10. The high cycling temperature clearly enhances electrochemical kinetics and activates more Li2MnO3 component, which gives high capacities, low cell impedance, and better rate capabilities. Moreover, it helps to form a relatively thick cathode-electrolyte interphase (CEI) film to suppress transition metal dissolution from the cathode surface. The upper cut-off voltage (UCV) of 3.0 V keeps the structural integrity of the cathode during cycling. A higher UCV of 3.2 V accelerates structural instabilities of the cathode as well as growth of the solid-electrolyte interphase (SEI) via transition metal dissolution and deposition on the anode surface. It results in higher cell impedance, worse capacity retention and faster capacity fade.

behind-the-meter storage↗
DOE OSTI2025

Characterizing Disorders Within Cathode Materials of Lithium‐Ion Batteries

The demand for developing high-energy density cathode materials has been increasing. The energy densities of cathode materials have been improved by adapting structural deviation from the ideal fully ordered α-NaFeO2 type, but that led to limitations in terms of structural stability and safety. Although disorders in cathode materials are closely related to their electrochemical properties, unfortunately, characterizing the disorder itself in cathode materials has been challenging due to its complex parasitic reaction and strong correlation with other disorders occurring during charge/discharge. In this review, we categorize various disorders by their scales of ordering from short-range to long-range. We addressed the principles of various characterization tools to figure out how they can help to identify the structural disorder in cathode materials. Specifically, we focused on the underlying principles of each characterization technique to correlate different disorder-driven phenomena through several case studies. It underscores the substantial importance of disorder-property relationships and the corresponding characterization methods, which can provide novel research strategies for developing high-energy density cathode materials with decent structural stability.

Lee, Hakwoo↗
DOE OSTI2025

In-Situ FTIR Detection of Transition Metal (TM)-Ion Dissolution From Cathodes in Li-Ion Batteries

Transition metal (TM) ions, commonly Ni and Mn, play a crucial role in Li-ion battery cathodes as the reaction centers for rapid redox reactions. A major challenge with TM-based cathodes is capacity degradation, particularly at higher operating voltages. This degradation is closely linked to the dissolution of TMs from the cathode materials and their subsequent deposition on the anode. This process not only modifies the surface structure of the cathode but, more significantly, alters the SEI composition on the anode [1-2]. The dissolution of TMs cations into a liquid electrolyte from cathode materials, such as Mn-ion dissolution from Mn-rich cathode (LMR), is detrimental to the cycling performance of Li-ion batteries [3-4]. Much attention has been paid to this issue but there remains a lack of characterization techniques which can detect the TM-ion dissolution from the cathode during electrochemical measurements. In our study, we use in-situ ATR-FTIR as an effective technique to probe the TM-ion dissolution from the cathode. We have first demonstrated the detrimental effects of TM ions on the electrochemical performance of Li-ion batteries by adding a small amount of TM salt (50 mM Mn(PF6)) to the electrolyte of a Li-ion coin cell with LFP and graphite electrode. We observed a rapid capacity fade after the first delithiation cycle. To investigate TM ion dissolution, we established a baseline IR spectrum for various TM solvation states (such as Mn and Ni) by measuring concentration-dependent IR spectra. This baseline spectrum helps us detect TM ion dissolution during battery cycling. In this work, we discuss in detail the effect of TM ions on the electrochemical performance of Li-ion batteries and the detection of TM ions during battery cycling using in-situ FTIR spectroscopy. We will compare TM dissolution between coated and uncoated cathodes to examine the effect of cathode coatings to mitigate degradation due to TM dissolution and cross-over from cathode to anode. References: (1) Zhan, C.; Wu, T.; Lu, J.; Amine, K. Dissolution, migration, anddeposition of transition metal ions in Li-ion batteries exemplified byMn-based cathodes - a critical review. Energy Environ. Sci. 2018, 11,243-257. (2) Jung, R.; Linsenmann, F.; Thomas, R.; Wandt, J.; Solchenbach,S.; Maglia, F.; Stinner, C.; Tromp, M.; Gasteiger, H. A. Nickel,Manganese, and Cobalt Dissolution from Ni-Rich NMC and TheirEffects on NMC622-Graphite Cells. J. Electrochem. Soc. 2019, 166,A378-A389. (3) Zhao, L.; Chenard, E.; Capraz, O. O.; Sottos, N. R.; White, S.R. Direct Detection of Manganese Ions in Organic Electrolyte by UV-Vis Spectroscopy. J. Electrochem. Soc. 2018, 165, A345-A348 (4) Zhang, Y.; Hu, A.; Xia, D.; Hwang, S.; Sainio, S.; Nordlund, D.;Michel, F. M.; Moore, R. B.; Li, L.; Lin, F. Operando characterization and regulation of metal dissolution and redeposition dynamics nearbattery electrode surface. Nat. Nanotechnol. 2023, 18, 790.

25 ENERGY STORAGE↗
DOE OSTI2020

Structural and Electrochemical Impacts of Mg/Mn Dual Dopants on the LiNiO 2 Cathode in Li-Metal Batteries

Doping chemistry has been regarded as an efficient strategy to overcome some fundamental challenges facing the “no-cobalt” LiNiO 2 cathode materials. By utilizing the doping chemistry, we evaluate the battery performance and structural/chemical reversibility of a new no-cobalt cathode material (Mg/Mn-LiNiO 2 ). The unique dual dopants drive Mg and Mn to occupy the Li site and Ni site, respectively. We report the Mg/Mn-LiNiO 2 cathode delivers smooth voltage profiles, enhanced structural stability, elevated self-discharge resistance, and inhibited nickel dissolution. As a result, the Mg/Mn-LiNiO 2 cathode enables improved cycling stability in lithium metal batteries with the conventional carbonate electrolyte: 80% capacity retention after 350 cycles at C /3, and 67% capacity retention after 500 cycles at 2 C (22 °C). We then take the Mg/Mn-LiNiO 2 as the platform to investigate the local structural and chemical reversibility, where we identify that the irreversibility takes place starting from the very first cycle. The highly reactive surface induces the surface oxygen loss, metal reduction reaching the subsurface, and metal dissolution. Our data demonstrate that the dual dopants can, to some degree, mitigate the irreversibility and improve the cycling stability of LiNiO 2 , but more efforts are needed to eliminate the key challenges of these materials for battery operation in the conventional carbonate electrolyte.

25 ENERGY STORAGE↗
DOE OSTI2021

Impact of secondary particle size and two-layer architectures on the high-rate performance of thick electrodes in lithium-ion battery pouch cells

Increasing lithium-ion battery gravimetric energy density to > 300 Wh/kg, while simultaneously meeting a cost target of $80/kWh, is of paramount importance to increasing the driving range and affordability of electric vehicles. One way to address this goal is to reduce inactive components by increasing electrode areal capacities, but conventional thick electrode designs typically perform poorly at high discharge rates due to Li + mass transport limitations. Here we compare the rate capability and cycle life of NMC 532/graphite pouch cells made with five different thick cathode and anode designs paired together in 25 combinations. We find that using different particle sizes to structure both the cathode and anode architectures in two-layer configurations results in a 2X capacity improvement over the worst-performing combination at high discharge rates (97 vs. 46 mAh/g at 2C). These different cathode/anode designs also translate to different cycle life performance, with many cells cycled at C/2 achieving ~80% capacity retention after 1000 cycles, and cells cycled at 2C showing different degrees of capacity fade. Altogether, these results demonstrate that simple, scalable changes in electrode design can significantly improve the performance of thick electrodes for high energy density batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

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↗
DOE OSTI2024

Tailoring Solvation Solvent in Localized High-Concentration Electrolytes for Lithium||Sulfurized Polyacrylonitrile

Sulfurized polyacrylonitrile (SPAN) is a promising cathode material for lithium-sulfur (Li-S) batteries due to its significantly reduced polysulfide (PS) dissolution compared to the elemental S cathode. Although conventional carbonate-based electrolytes is stable with SPAN electrodes, it is less stable with Li metal anode (LMA). Recently, localized high-concentration electrolytes (LHCEs) have been developed to improve the stability of LMA. Here, we report a new strategy to further improve the performance of LI||SPAN batteries by replacing the conventional solvating solvent 1,2-dimethoxyethane (DME) in the LHCE with a new solvating solvent, 1,2-diethoxyethane (DEE), the new LHCEs exhibits less reactivity against Li 2 S 2 , alleviates PS dissolution, forms a better cathode-electrolyte interphase layer on the SPAN, and enhances structure reversibility even at elevated temperature (ET, 45°C). With the same salt and diluent as in other LHCEs, the LHCE with DEE leads to better performance in Li||SPAN batteries (with 82.9% capacity retention after 300 cycles at ET), preservation of SPAN cathode structure, and suppression of the volume change of LMA. The similar strategy on tailoring the solvating solvents in LHCEs can also be used in other rechargeable batteries to improve their performances.

1,2-diethoxyethane↗
DOE OSTI2021

Understanding Co roles towards developing Co-free Ni-rich cathodes for rechargeable batteries

Reduction on cobalt reliance is an urgent requirement in the development of sustainable cathode materials for Li-ion batteries. Here the authors analyse the roles of cobalt and its interplay with other ions in high-nickel layered oxides, and deduce a material formula for promising cobalt-free cathodes. Current bottlenecks in cobalt (Co) supply have negatively impacted commercial battery production and inspired the development of cathode materials that are less reliant on Co. However, complete Co elimination is prevented by the lack of fundamental understanding of the impact of Co on cathode capacity and structural stability, as well as the lack of effective substitute components in practice. Here we investigate the roles of Co in purposely designed systems that include both Co-rich and Mn-substituted Co-free cathodes. Our results affirmed that Co plays an undeniable role in fast capacity and/or structural degradation, and found that Co is more destructive than Ni at high potentials, which offers unexpected but encouraging perspectives for Co reduction. Moreover, Mn substitution effectively alleviates the destructive effects of Co and enables a high potential functionality. Finally, with these fundamental discoveries, we demonstrated a series of LiNi α Mn β X γ O 2 (X = single or multiple dopants) as a promising candidate for Co-free cathodes.

25 ENERGY STORAGE↗