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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 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Na 3 MnZr(PO 4 ) 3 : A High-Voltage Cathode for Sodium Batteries

Sodium batteries have been regarded as promising candidates for large-scale energy storage application, provided cathode hosts with high energy density and long cycle life can be found. Herein, we report NASICON-structured Na 3 MnZr(PO 4 ) 3 as a cathode for sodium batteries that exhibits an electrochemical performance superior to those of other manganese phosphate cathodes reported in the literature. Both the Mn 4+ /Mn 3+ and Mn 3+ /Mn 2+ redox couples are reversibly accessed in Na 3 MnZr(PO 4 ) 3 , providing high discharge voltage plateaus at 4.0 and 3.5 V, respectively. A high discharge capacity of 105 mAh g –1 was obtained from Na 3 MnZr(PO 4 ) 3 with a small variation of lattice parameters and a small volume change on extraction of two Na + ions per formula unit. Moreover, Na 3 MnZr(PO 4 ) 3 exhibits an excellent cycling stability, retaining 91% of the initial capacity after 500 charge/discharge cycles at 0.5 C rate. On the basis of structural analysis and density functional theory calculations, we have proposed a detailed desodiation pathway from Na 3 MnZr(PO 4 ) 3 where Mn and Zr are disordered within the structure. We further show that the cooperative Jahn–Teller distortion of Mn 3+ is suppressed in the cathode and that Na 2 MnZr(PO 4 ) 3 is a stable phase

Chemistry↗
DOE OSTI2020

Multiprincipal Component P2-Na 0.6 (Ti 0.2 Mn 0.2 Co 0.2 Ni 0.2 Ru 0.2 )O 2 as a High-Rate Cathode for Sodium-Ion Batteries

Mixing transition metal cations in nearly equiatomic proportions in layered oxide cathode materials is a new strategy for improving the performances of Na-ion batteries. The mixing of cations not only offers entropic stabilization of the crystal structure but also benefits the diffusion of Na ions with tuned diffusion activation energy barriers. In light of this strategy, a high-rate Na 0.6 (Ti 0.2 Mn 0.2 Co 0.2 Ni 0.2 Ru 0.2 )O 2 cathode was designed, synthesized, and investigated, combining graph-based deep learning calculations and complementary experimental characterizations. This new cathode material delivers high discharge capacities of 164 mA g –1 at 0.1 C and 68 mAh g –1 at a very high rate of 86 C, demonstrating an outstanding high rate capability. Ex situ and operando synchrotron X-ray diffraction were used to reveal the detailed structural evolution of the cathode upon cycling. Using the climbing-image nudged elastic-band calculation and Ab initio molecular dynamics simulations, we show that the optimal transition metal composition enables a percolating network of low barrier pathways for fast, macroscopic Na diffusion, resulting in the observed high rate performance.

25 ENERGY STORAGE↗
DOE OSTI2016

Anion-redox nanolithia cathodes for Li-ion batteries

The development of lithium-air batteries is plagued by a high potential gap (>1.2 V) between charge and discharge, and poor cyclability due to the drastic phase change of O-2 (gas) and Ox- (condensed phase) at the cathode during battery operations. Here we report a cathode consisting of nanoscale amorphous lithia (nanolithia) confined in a cobalt oxide, enabling charge/discharge between solid Li2O/Li2O2/LiO2 without any gas evolution. The cathode has a theoretical capacity of 1,341 Ah kg(-1), a mass density exceeding 2.2 g cm(-3), and a practical discharge capacity of 587 Ah kg(-1) at 2.55V versus Li/Li+. It also displays stable cycling performance (only 1.8% loss after 130 cycles in lithium-matched full-cell tests against Li4Ti5O12 anode), as well as a round-trip overpotential of only 0.24V. Interestingly, the cathode is automatically protected from O-2 gas release and overcharging through the shuttling of self-generated radical species soluble in the carbonate electrolyte.

Zhu, Zhi↗
DOE OSTI2019

Cathode porosity is a missing key parameter to optimize lithium-sulfur battery energy density

While high sulfur loading has been pursued as a key parameter to build realistic high-energy lithium-sulfur batteries, less attention has been paid to the cathode porosity, which is much higher in sulfur/carbon composite cathodes than in traditional lithium-ion battery electrodes. For high-energy lithium-sulfur batteries, a dense electrode with low porosity is desired to minimize electrolyte intake, parasitic weight, and cost. Here we report the profound impact on the discharge polarization, reversible capacity, and cell cycling life of lithium-sulfur batteries by decreasing cathode porosities from 70 to 40%. According to the developed mechanism-based analytical model, we demonstrate that sulfur utilization is limited by the solubility of lithium-polysulfides and further conversion from lithium-polysulfides to Li2S is limited by the electronically accessible surface area of the carbon matrix. Finally, we predict an optimized cathode porosity to maximize the cell level volumetric energy density without sacrificing the sulfur utilization.

25 ENERGY STORAGE↗
DOE OSTI2022

Thermal-healing of lattice defects for high-energy single-crystalline battery cathodes

Abstract Single-crystalline nickel-rich cathodes are a rising candidate with great potential for high-energy lithium-ion batteries due to their superior structural and chemical robustness in comparison with polycrystalline counterparts. Within the single-crystalline cathode materials, the lattice strain and defects have significant impacts on the intercalation chemistry and, therefore, play a key role in determining the macroscopic electrochemical performance. Guided by our predictive theoretical model, we have systematically evaluated the effectiveness of regaining lost capacity by modulating the lattice deformation via an energy-efficient thermal treatment at different chemical states. We demonstrate that the lattice structure recoverability is highly dependent on both the cathode composition and the state of charge, providing clues to relieving the fatigued cathode crystal for sustainable lithium-ion batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Enabling high energy lithium metal batteries via single-crystal Ni-rich cathode material co-doping strategy

High-capacity Ni-rich layered oxides are promising cathode materials for secondary lithium-based battery systems. However, their structural instability detrimentally affects the battery performance during cell cycling. Here, we report an Al/Zr co-doped single-crystalline LiNi<:sub>0.88 Co 0.09 Mn 0.03 O 2 (SNCM) cathode material to circumvent the instability issue. We found that soluble Al ions are adequately incorporated in the SNCM lattice while the less soluble Zr ions are prone to aggregate in the outer SNCM surface layer. The synergistic effect of Al/Zr co-doping in SNCM lattice improve the Li-ion mobility, relief the internal strain, and suppress the Li/Ni cation mixing upon cycling at high cut-off voltage. These features improve the cathode rate capability and structural stabilization during prolonged cell cycling. In particular, the Zr-rich surface enables the formation of stable cathode-electrolyte interphase, which prevent SNCM from unwanted reactions with the non-aqueous fluorinated liquid electrolyte solution and avoid Ni dissolution. To prove the practical application of the Al/Zr co-doped SNCM, we assembled a 10.8 Ah pouch cell (using a 100 μm thick Li metal anode) capable of delivering initial specific energy of 504.5 Wh kg- 1 at 0.1 °C and 25 °C.

25 ENERGY STORAGE↗
DOE OSTI2025

Multicationic interactions mitigating lattice strain in sodium layered cathodes

Transition-metal (TM) layered oxides have emerged as the primary cathode choice for sodium-ion batteries (SIBs) due to their high energy density and sustainable chemistry using non-critical elements. However, their anisotropic lattice strain and stress accumulation during (de)sodiation lead to severe structural degradation, yet an intrinsic strain-depressant approach remains elusive. Herein, we propose entropy regulation with zero Li/Co usage to mitigate harmful lattice displacements and enhance the electrochemical performance of sodium layered cathodes. Our findings demonstrate that high entropy design effectively inhibits TMO 6 octahedra distortions upon cycling, as evidenced by hard X-ray absorption spectroscopy, greatly reducing near-surface structural deconstruction and interface side reactions. Furthermore, multicationic interactions driven by configurational entropy thermodynamically mitigate the formation of oxygen defects and strengthen ligand-to-metal coordination. The complementarity inherent in charge compensation within complex systems is unveiled and the restrained lattice parameters deviations without interior volume residuals are successfully achieved. As a result, the multicationic cathode exhibits improved cycling stability and Na + diffusion kinetics in both half and full cells. The cathode chemistries outlined here broaden the prospects for lattice engineering to alleviate bulk fatigue and open up the possibility to develop an economically viable layered oxides with long durability.

Wang, Haoji [Central South University, Changsha (C↗
DOE OSTI2025

Topotaxially grown composite cathodes for cobalt-free high-energy long-life Li-ion batteries

The vehicle industry’s increasing demand for electrification necessitates the removal of expensive and rare cobalt from current high-energy batteries. However, eliminating cobalt poses challenges due to its vital role in maintaining the layered structural ordering and cycling stability of commonly used Li(NiMnCo)O 2 cathodes. As an alternative to conventional layered oxide designs, we report a lithium nickelate cathode with a composite structure comprising major stoichiometric layered and minor rocksalt phases within the same oxygen lattice. This material outperforms conventional designs by maintaining stable battery operation at voltages up to 4.8 V vs. Li|Li + , with 88% capacity retention after 1000 cycles at 2C. The topotaxial-growth-enabled interlock between the two components mitigates chemo-mechanical degradation, offering a promising pathway to cobalt-free cathodes. Additionally, we reveal a miscibility gap in the Li-Ni-O system that enables kinetic adjustment of composition and structure during sintering, thereby tuning the functionality of high-energy cathodes.

25 ENERGY STORAGE↗
DOE OSTI2020

A charge-density-based general cation insertion algorithm for generating new Li-ion cathode materials

Future lithium (Li) energy storage technologies, in particular solid-state configurations with a Li metal anode, opens up the possibility of using cathode materials that do not necessarily contain Li in its as-made state. To accelerate the discovery and design of such materials, we develop a general, chemically, and structurally agnostic methodology for identifying the optimal Li sites in any crystalline material. For a given crystal structure, we attempt multiple Li insertions at symmetrically in-equivalent positions by analyzing the electronic charge density obtained from first-principles density functional theory. In this report, we demonstrate the effectiveness of this procedure in successfully identifying the positions of the Li ion in well-known cathode materials using only the empty host (charged) material as guidance. Furthermore, applying the algorithm to over 2000 candidate cathode empty host materials we obtain statistics of Li site preferences to guide future developments of novel Li-ion cathode materials, particularly for solid-state applications.

25 ENERGY STORAGE↗
DOE OSTI2024

Earth-abundant Li-ion cathode materials with nanoengineered microstructures

Manganese-based materials have tremendous potential to become the next-generation lithium-ion cathode as they are Earth abundant, low cost and stable. Here we show how the mobility of manganese cations can be used to obtain a unique nanosized microstructure in large-particle-sized cathode materials with enhanced electrochemical properties. By combining atomic-resolution scanning transmission electron microscopy, four-dimensional scanning electron nanodiffraction and in situ X-ray diffraction, we show that when a partially delithiated, high-manganese-content, disordered rocksalt cathode is slightly heated, it forms a nanomosaic of partially ordered spinel domains of 3–7 nm in size, which impinge on each other at antiphase boundaries. The short coherence length of these domains removes the detrimental two-phase lithiation reaction present near 3 V in a regular spinel and turns it into a solid solution. This nanodomain structure enables good rate performance and delivers 200 mAh g –1 discharge capacity in a (partially) disordered material with an average primary particle size of ~5 µm. The work not only expands the synthesis strategies available for developing high-performance Earth-abundant manganese-based cathodes but also offers structural insights into the ability to nanoengineer spinel-like phases.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Origin of structural degradation in Li-rich layered oxide cathode

Li- and Mn-rich (LMR) cathode materials that utilize both cation and anion redox can yield substantial increases in battery energy density 1,2,3 . However, although voltage decay issues cause continuous energy loss and impede commercialization, the prerequisite driving force for this phenomenon remains a mystery 3,4,5,6 In this work, with in situ nanoscale sensitive coherent X-ray diffraction imaging techniques, we reveal that nanostrain and lattice displacement accumulate continuously during operation of the cell. Evidence shows that this effect is the driving force for both structure degradation and oxygen loss, which trigger the well-known rapid voltage decay in LMR cathodes. By carrying out micro- to macro-length characterizations that span atomic structure, the primary particle, multiparticle and electrode levels, we demonstrate that the heterogeneous nature of LMR cathodes inevitably causes pernicious phase displacement/strain, which cannot be eliminated by conventional doping or coating methods. We therefore propose mesostructural design as a strategy to mitigate lattice displacement and inhomogeneous electrochemical/structural evolutions, thereby achieving stable voltage and capacity profiles. These findings highlight the significance of lattice strain/displacement in causing voltage decay and will inspire a wave of efforts to unlock the potential of the broad-scale commercialization of LMR cathode materials.

25 ENERGY STORAGE↗
DOE OSTI2024

Low-cost iron trichloride cathode for all-solid-state lithium-ion batteries

The dominant chemistries of lithium-ion batteries on the market today still rely on flammable organic liquid electrolytes and cathodes containing scarce metals, such as cobalt or nickel, raising safety, cost and environmental concerns. Here we show a FeCl 3 cathode that costs as little as 1% of the cost of a LiCoO 2 cathode or 2% of a LiFePO 4 cathode. Once coupled with a solid halide electrolyte and a lithium-indium (Li–In) alloy anode, it enables all-solid-state lithium-ion batteries without any liquid components. Notably, FeCl 3 exhibits two flat voltage plateaux between 3.5 and 3.8 V versus Li + /Li, and the solid cell retains 83% of its initial capacity after 1,000 cycles with an average Coulombic efficiency of 99.95%. Combined neutron diffraction and X-ray absorption spectroscopy characterizations reveal a Li-ion (de)intercalation mechanism together with a Fe 2+ /Fe 3+ redox process. Further, our work provides a promising avenue for developing sustainable battery technologies with a favourable balance of performance, cost and safety.

25 ENERGY STORAGE↗
DOE OSTI2016

Exceptional energy and new insight with a sodium–selenium battery based on a carbon nanosheet cathode and a pseudographite anode

We created a unique sodium ion battery (NIB, SIB) cathode based on selenium in cellulose-derived carbon nanosheets (CCNs), termed Se-CCN. The elastically compliant two-dimensional CCN host incorporates a high mass loading of amorphous Se (53 wt%), which is primarily impregnated into 1 cm 3 g -1 nanopores. The results in facile sodiation kinetics due to short solid-state diffusion distances and a large charge transfer area of the nanosheets were established. The architecture also leads to an intrinsic resistance to polyselenide shuttle and to disintegration/coarsening. As a Na half-cell, the Se-CCN cathode delivers a reversible capacity of 613 mA h g -1 with 88% retention over 500 cycles. The exceptional stability is achieved by using a standard electrolyte (1 M NaClO4 EC-DMC) without secondary additives or high salt concentrations. The rate capability is also superb, achieving 300 mA h g -1 at 10C. Compared to recent state-of-the-art literature, the Se-CCN is the most cyclically stable and offers the highest rate performance. As a Se–Na battery, the system achieves 992 W h kg -1 at 68 W kg -1 and 384 W h kg -1 at 10144 W kg -1 (by active mass in a cathode). We are the first to fabricate and test a Se-based full NIB, which is based on Se-CCN coupled to a Na intercalating pseudographitic carbon (PGC) anode. It is demonstrated that the PGC anode increases its structural order in addition to dilating as a result of Na intercalation at voltages below 0.2 V vs. Na/Na+. The {110} Na reflections are distinctly absent from the XRD patterns of PGC sodiated down to 0.001 V, indicating that the Na metal pore filling is not significant for pseudographitic carbons. Lastly, the battery delivers highly promising Ragone chart characteristics, for example yielding 203 and 50 W h kg -1 at 70 and 14 000 W kg -1 (via total material mass in the anode and cathode).

25 ENERGY STORAGE↗
DOE OSTI2017

Highly flexible, freestanding tandem sulfur cathodes for foldable Li–S batteries with a high areal capacity

Li–S batteries with a high theoretical capacity are considered as the most promising candidate to satisfy the increasing demand for batteries with a high areal capacity. However, the low sulfur loading (<2 mg cm -2 ) and poor flexibility of current Li–S batteries limit their application in establishing foldable Li–S batteries with a high areal capacity. Here, to solve this problem, we employ here a free-standing flexible tandem sulfur cathode with a remarkably high sulfur loading to demonstrate foldable, high-areal-capacity Li–S batteries. The design of the tandem cathode readily increases the sulfur loading and effectively retards the migration of polysulfides. Therefore, the Li–S cell employing the tandem cathode exhibits a high initial areal capacity of 12.3 mA h cm -2 with stable cycling stability even with a high sulfur loading of up to 16 mg cm -2 . These tandem cathodes are promising for foldable Li–S cells with a high areal capacity and energy density.

25 ENERGY STORAGE↗
DOE OSTI2019

Thermally-driven mesopore formation and oxygen release in delithiated NCA cathode particles

The structural integrity of layered Ni-rich oxide cathode materials is one of the most significant factors that critically affect the performance and reliability of lithium-ion batteries. Prolonged battery operation many times involves repeated phase transitions, buildup of mechanical stresses, and could provoke thermal spikes. Such sophisticated chemo-thermo-mechanical interplay can cause performance degradation through structural disintegration of the cathode active materials (CAMs). In this work, we systematically investigate the thermal decomposition, fracture, and oxygen evolution of chemically delithiated Li 0.3 Ni 0.8 Co 0.15 Al 0.05 O 2 (NCA) particles upon heating from 25 °C to 450 °C using a number of advanced X-ray and electron probes. We observed a continuous reduction of the Ni oxidation state upon heating, as well as the release of oxygen from the NCA lattice that undergoes the thermally induced phase transformations. The release of oxygen also created numerous mesopores throughout the analyzed particles, which could significantly affect the chemical and mechanical properties of the electrode. In addition, intergranular and intragranular fracturing at elevated temperatures also contribute to the degradation of the NCA cathode under these conditions. Our investigation of the mechanical integrity at elevated temperatures provides a fundamental understanding of the thermally driven chemomechanical breakdown of the NCA cathode active materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Strain-driven surface reconstruction and cation segregation in layered Li(Ni 1– x – y Mn x Co y )O 2 (NMC) cathode materials

The composition, structure and phase transformations occurring on cathode surfaces greatly affect the performance of Li-ion batteries. Li-Ion diffusion and surface–electrolyte interaction are two major phenomena that impact the capacity and cell impedance. The effects of surface reconstruction (SR) of cathode materials on the performance of Li-ion batteries are of current interest. However, the origin and evolution of the SR are still not well understood. In this work, density functional theory (DFT) calculations are used to investigate the processes taking place during surface segregation and reconstruction. Facet dependent segregation was found in Li(Ni 1– x – y Mn x Co y )O 2 (NMC) cathodes. Specifically, Co tends to segregate to the (104) surface of the primary particles within the transition metal layer, while Ni ions tend to segregate to the (012) surface in the Li layer, forming a SR. Experimental evidence shows the SR to be epitaxial with the bulk of the as-synthesized material, and the new SR phase is pinned to the NMC unit cell leading to a strained SR. Here, we demonstrate that strain can stabilize a spinel structure of the SR layers. Understanding the effects of surface strain opens a new avenue for the design of cathode materials with enhanced surface properties.

25 ENERGY STORAGE↗
DOE OSTI2021

Revisiting the role of Zr doping in Ni-rich layered cathodes for lithium-ion batteries

We report the realization of high performance Ni-rich layered cathodes remains a challenge because of the multiple degradation factors that concurrently operate during battery cycling. In particular, depletion of oxygen charge and consequent lattice oxygen instability at deep charge state accelerate the subsequent chemomechanical degradation mechanisms. Among the proposed methodologies, doping has proven to be effective in enhancing the cathode cycle life by stabilizing the layered structure. Herein, we achieved the electrochemically stabilized Ni-rich LiNi 0.92 Co 0.04 Mn 0.04 O 2 through Zr doping, resulting in a 15% increase of the capacity retention after 100 cycles. In-depth investigations are conducted to unveil the effects of Zr doping on the layered cathode, and in particular, the critical role of Zr doping on the lattice oxygen stability is systematically studied. By combining state-of-the-art magnetometer characterization, X-ray analysis, and first-principles calculation, we reveal that Zr doping positively contributes the to lattice oxygen stability by alleviating the oxygen charge loss at deep charge, thereby improving the cathode electrochemical reversibility. Our findings provide an insight into the Zr doping mechanism and help to design the Ni-rich layered oxides for future applications.

25 ENERGY STORAGE↗
DOE OSTI2021

Effect of cathode on crosstalk in Si-based lithium-ion cells

Crosstalk between the cathode and the anode in Li-ion batteries has a great impact on performance, safety and cycle lifetime. However, a systematic investigation of crosstalk behavior in silicon (Si)-based cells with various cathode materials has not been reported. We investigated the crosstalk behavior of a Si anode coupled with one of the following cathodes—LiCoO 2 (LCO), LiNi 0.5 Mn 0.3 Co 0.2 (NMC532), and LiFePO 4 (LFP)—in a full cell. For each electrochemical couple, we compared electrolyte decomposition products, solid electrolyte interphase (SEI) chemistry, and degradation mechanisms during cycling. From a very early stage of cycling, each couple showed different crosstalk behavior; different electrolyte decomposition products and SEI chemistry on the Si anodes were seen. Specifically, the formation and growth mechanism of Si SEI differ depending on cathode materials. For the LFP system, the Si SEI rich in LiF and inorganic species, which is stable and robust. It forms at an early stage of cycle. As a result, the SEI of Si from the LFP system well tolerates SEI breakage due to mechanical changes of Si and suppresses Li loss, resulting in stable cycle life.

25 ENERGY STORAGE↗