Double-Layered Perovskite Oxyfluoride Cathodes with High Capacity Involving O–O Bond Formation for Fluoride-Ion Batteries

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(6), С. 3844 - 3853

Опубликована: Янв. 9, 2024

Developing electrochemical high-energy storage systems is of crucial importance toward a green and sustainable energy supply. A promising candidate fluoride-ion batteries (FIBs), which can deliver much higher volumetric density than lithium-ion batteries. However, typical metal fluoride cathodes with conversion-type reactions cause low-rate capability. Recently, layered perovskite oxides oxyfluorides, such as LaSrMnO4 Sr3Fe2O5F2, have been reported to exhibit relatively high rate performance cycle stability compared reactions, but their discharge capacities (∼118 mA h/g) are lower those used in Here, we show that double-layered oxyfluoride La1.2Sr1.8Mn2O7−δF2 exhibits (de) intercalation two ions rock-salt slabs further excess the layer, leading reversible capacity 200 h/g. The additional leads formation O–O bond structure for charge compensation (i.e., anion redox). These results highlight oxyfluorides new class active materials construction high-performance FIBs.

Язык: Английский

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Does trapped O₂ form in the bulk of LiNiO₂ during charging?

Energy & Environmental Science, Год журнала: 2024, Номер 17(7), С. 2530 - 2540

Опубликована: Янв. 1, 2024

The charge storage mechanism in LiNiO 2 Li-ion batteries is still under debate. Here, we show that trapped O forms during delithiation , accommodated by Ni vacancies, which form the layer.

Язык: Английский

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Jahn–Teller Distortions and Phase Transitions in LiNiO₂: Insights from Ab Initio Molecular Dynamics and Variable-Temperature X-ray Diffraction

Chemistry of Materials, Год журнала: 2024, Номер 36(5), С. 2289 - 2303

Опубликована: Фев. 20, 2024

The atomistic structure of lithium nickelate (LiNiO2), the parent compound Ni-rich layered oxide cathodes for Li-ion batteries, continues to elude a comprehensive understanding. common consensus is that material exhibits local Jahn–Teller distortions dynamically reorient, resulting in time-averaged undistorted R3̅m structure. Through combination ab initio molecular dynamics (AIMD) simulations and variable-temperature X-ray diffraction (VT-XRD), we explore LiNiO2 as function temperature. Static are observed at low temperatures (T < 250 K) via AIMD simulations, followed by broad phase transition occurs between 350 K, leading highly dynamic, displacive high > K), which does not show four short two long bonds characteristic distortions. These transitions abrupt changes calculated pair distribution bond-length distortion index monoclinic lattice parameter ratio, amon/bmon, δ angle, fit quality an R3̅m-based structural refinement, peak sharpening peaks on heating, consistent with loss distorted domains. Between mixed-phase regime found where domains coexist. repeated change states this allows axes direction. pseudorotations Ni–O side effect onset transition. Antisite defects, involving Li ions Ni layer layer, pin temperatures, impeding cooperative ordering longer length scale.

Язык: Английский

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Identification of the dual roles of Al₂O₃ coatings on NMC811-cathodes via theory and experiment

Energy & Environmental Science, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Aluminium oxide coatings on Ni-rich layered materials have the dual functions of scavenging protic and acidic species from electrolyte, in stabilising surface oxygen against chemical oxidation electrolyte at high potentials.

Язык: Английский

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A Critical Analysis of Chemical and Electrochemical Oxidation Mechanisms in Li-Ion Batteries

The Journal of Physical Chemistry Letters, Год журнала: 2024, Номер 15(2), С. 391 - 400

Опубликована: Янв. 4, 2024

Electrolyte decomposition limits the lifetime of commercial lithium-ion batteries (LIBs) and slows adoption next-generation energy storage technologies. A fundamental understanding electrolyte degradation is critical to rationally design stable energy-dense LIBs. To date, most explanations for at LIB positive electrodes have relied on ethylene carbonate (EC) being chemically oxidized by evolved singlet oxygen (1O2) or electrochemically oxidized. In this work, we apply density functional theory assess feasibility these mechanisms. We find that electrochemical oxidation unfavorable any potential reached during normal operation, predict previously reported reactions between EC 1O2 are kinetically limited room temperature. Our calculations suggest an alternative mechanism in which reacts with superoxide (O2–) and/or peroxide (O22–) anions. This work provides a new perspective motivates further studies understand reactivity electrodes.

Язык: Английский

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Elucidating Gas Evolution of Prussian White Cathodes for Sodium‐ion Battery Application: The Effect of Electrolyte and Moisture

Batteries & Supercaps, Год журнала: 2024, Номер 7(4)

Опубликована: Янв. 15, 2024

Abstract As global energy storage demand increases, sodium‐ion batteries are often considered as an alternative to lithium‐ion batteries. Hexacyanoferrate cathodes, commonly referred Prussian blue analogues (PBAs), of particular interest due their low‐cost synthesis and promising electrochemical response. However, because they consist ~50 wt% cyanide anions, a possible release highly toxic gases poses significant safety risk. Previously, we observed the evolution (CN) 2 during cycling via differential mass spectrometry (DEMS), but were unable determine root cause or mechanism. In this work, present systematical investigation gas white (PW) with different water content DEMS. While H is main detected, especially in hydrated PW overcharge (4.6 V vs. Na + /Na), CO depends on electrolyte conductive salt. The use oxidative NaClO 4 instead NaPF 6 leading for formation . Mass spectrometric evidence trace amounts HCN also found, much lower extent than , which dominant risk when using ‐containing electrolyte, despite being good model salt, not viable option commercial applications.

Язык: Английский

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Quantifying Electrochemical Degradation in Single-Crystalline LiNi0.8Mn0.1Co0.1O

PRX Energy, Год журнала: 2024, Номер 3(1)

Опубликована: Янв. 23, 2024

Using lab-based operando X-ray and post-mortem techniques, researchers visualize the origins of electrochemical capacity fade under high-voltage conditions in pilot line single-crystalline LiNi${}_{0.8}$Mn${}_{0.1}$Co${}_{0.1}$O${}_{2}$-graphite cells.

Язык: Английский

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Advances and perspectives in understanding the structure-redox relationship of layered Li-Co-Ni-Mn oxide cathode materials

Progress in Materials Science, Год журнала: 2024, Номер 143, С. 101247 - 101247

Опубликована: Фев. 9, 2024

Язык: Английский

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Probing Jahn–Teller Distortions and Antisite Defects in LiNiO₂ with ⁷Li NMR Spectroscopy and Density Functional Theory

Chemistry of Materials, Год журнала: 2024, Номер 36(9), С. 4226 - 4239

Опубликована: Апрель 24, 2024

The long- and local-range structure electronic properties of the high-voltage lithium-ion cathode material for Li-ion batteries, LiNiO

Язык: Английский

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Influence of Carbonate Electrolyte Solvents on Voltage and Capacity Degradation in Li‐Rich Cathodes for Li‐ion Batteries

Advanced Energy Materials, Год журнала: 2024, Номер 14(32)

Опубликована: Май 22, 2024

Abstract Lithium‐rich cobalt‐free cathodes, such as Li 1.2 Mn 0.6 Ni 0.2 O 2 (LMR), are promising next‐generation cathode materials because of their high energy density, cost efficiency, and sustainability. Nevertheless, LMRs suffer from degradation problems voltage decay during cycling. Different LMR surface doping coating strategies proposed to suppress with varying extents success. Here, the role played by different electrolyte solvents in oxygen loss is instead investigated. X‐ray absorption spectroscopy (XAS), electron (EELS), synchrotron XRD, online electrochemical mass spectrometry (OEMS) results show that ethylene carbonate (EC) leads accelerated surface. As a result, cycling cathodes EC‐free electrolytes pure EMC, improves capacity retention reduces decay. This approach provides new strategy increase stability which important for development more sustainable high‐performance batteries.

Язык: Английский

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