Enabling the high capacity of lithium-rich anti-fluorite lithium iron oxide by simultaneous anionic and cationic redox

Zhan, Chun; Yao, Zhenpeng; Lü, Jun; Ma, Lu; Maroni, V.A.; Li, Liang; Lee, Eungje; Esen, E.; Wu, Tianpin; Wen, Jianguo; Ren, Yang; Johnson, Christopher; Thackeray, Michael M.; Chan, Maria K. Y.; Wolverton, Chris; Amine, Khalil

doi:10.1038/s41560-017-0043-6

Cited by 151 publications

(196 citation statements)

References 41 publications

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“…Based on the collective structural and electronic results above, we argue that observed capacity beyond that expected for an endpoint of NaIrO 3 (recorded in the first charge for Na 2− x IrO 3 ) is attributable neither to an increase in Ir oxidation state from Ir 5+ toward Ir 6+ (i.e., additional Na removal) nor with a pronounced change in a bulk oxygen oxidation state, a process that has recently been discussed for Li‐ and Na‐rich cathode materials . It is plausible that the added capacity derives from oxidation of impurities inevitably populating the surface and interface structure of the material or other electrolyte contributions and is thus extrinsic to bulk Na 2− x IrO 3 .…”

Section: Resultsmentioning

confidence: 69%

Fundamental Insights from a Single‐Crystal Sodium Iridate Battery

Tepavcevic

Zheng

Hinks

et al. 2020

Advanced Energy Materials

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Electrochemically driven chemical transformations play the key role in controlling storage of energy in chemical bonds and subsequent conversion to power electric vehicles and consumer electronics. The promise of coupling anionic oxygen redox with cationic redox to achieve a substantial increase in capacities has inspired research in a wide range of electrode materials. A key challenge is that these studies have focused on polycrystalline materials, where it is hard to perform precise structural determinations, especially related to the location of light atoms. Here a different approach is utilized and a highly ordered single crystal, Na2−xIrO3 is harnessed, to explore the role of defects and structural transformations in layered transition metal oxide materials on redox‐activity, capacity, reversibility, and stability. Within a combined experimental and theoretical framework, it is demonstrated that 1) it is possible to cycle Na2−xIrO3, offering proof of principle for single‐crystal based batteries 2) structural phase transitions coincide with Ir 4+/Ir 5+ redox couple with no evident contribution from anionic redox 3) strong irreversibility and capacity fade observed during cycling correlates with the Na + migration resulting in progressive growth of an electrochemically inert O3‐type NaIrO3 phase.

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Section: Resultsmentioning

confidence: 69%

Fundamental Insights from a Single‐Crystal Sodium Iridate Battery

Tepavcevic

Zheng

Hinks

et al. 2020

Advanced Energy Materials

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“…On the other hand, almost all the oxygen-redox active electrodes involve cationic redox reactions, simultaneously or separately. 35,36 As directly shown later in this work, even for a system with nominally pure oxygen redox, TM redox will emerge with electrochemical cycling and affects the oxygen redox. Direct probes of TM redox, together with oxygen redox, will provide a consistent and experimental clarification of the reaction mechanism responsible for the total capacity, as well as the critical relationship between the anionic and cationic redox.…”

Section: Introductionmentioning

confidence: 65%

High Reversibility of Lattice Oxygen Redox Quantified by Direct Bulk Probes of Both Anionic and Cationic Redox Reactions

Dai

Zhuo

et al. 2019

Joule

246

371

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The reversibility and cyclability of anionic redox in battery electrodes hold the key to its practical employments. Here, through mapping of resonant inelastic X-ray scattering (mRIXS), we have independently quantified the evolving redox states of both cations and anions in Na2/3Mg1/3Mn2/3O2. The bulk-Mn redox emerges from initial discharge and is quantified by inverse-partial fluorescence yield (iPFY) from Mn-L mRIXS. Bulk and surface Mn activities likely lead to the voltage fade. O-K superpartial fluorescence yield (sPFY) analysis of mRIXS shows 79% lattice oxygen-redox reversibility during initial cycle, with 87% capacity sustained after 100 cycles. In Li1.17Ni0.21Co0.08Mn0.54O2, lattice-oxygen redox is 76% initial-cycle reversible but with only 44% capacity retention after 500 cycles. These results unambiguously show the high reversibility of lattice-oxygen redox in both Li-ion and Na-ion systems. The contrast between Na2/3Mg1/3Mn2/3O2 and Li1.17Ni0.21Co0.08Mn0.54O2 systems suggests the importance of distinguishing lattice-oxygen redox from other oxygen activities for clarifying its intrinsic properties.

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“…First-principles density functional theory (DFT) calculations have been extensively used as compelling tools to study the battery materials by understanding the underlying mechanisms, [36][37][38][39][40][41] exploring the kinetics during electrochemical reactions, [42][43][44][45] and predicting novel high-performance electrode materials. [46][47][48][49] Here in this work, we use DFT to investigate the Sn-Ca electrochemical alloy reaction process via constructing the ground-state Sn-Ca phase diagram and explore the reaction driving force evolution as a function of Ca-ion accommodated.…”

Section: Introductionmentioning

confidence: 99%

Discovery of Calcium‐Metal Alloy Anodes for Reversible Ca‐Ion Batteries

Yao

Hegde

Aspuru‐Guzik

et al. 2019

Advanced Energy Materials

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techniques with high energy density and low cost. [1] Multivalent batteries, like Mg-ion, [2] Ca-ion, [3,4] and Al-ion batteries, [5,6] have the potential to realize significantly improved capacities, compared to monovalent batteries (e.g., Li-ion batteries), due to more electrons carried per ion. Among them, Ca-ion batteries (CIB) have drawn special attention with merits besides the capacity enhancement:(1) Ca/Ca 2+ has a reduction potential (−2.87 V) only slightly higher than Li/Li + (−3.04 V), yet much lower than Mg/Mg 2+ (−2.36 V) and Al/Al 3+ (−1.68 V), which provides CIB the prospect to function at voltages comparable with Li-ion batteries and much higher than the counterparts of Mg-ion and Al-ion batteries. [7,8] (2) Ca is the fifth most abundant element in the earth's crust with an extensive global resource distribution, in contrast to lithium. (3) The kinetics of Ca-ion in solid electrodes are faster than Mg-and Al-ions due to reduced charge density. [9][10][11] The development of CIBs was originally pioneered by the study of Ca-ion electrochemical intercalations into layered transition metal oxides and sulfides. [12] Subsequently, many efforts then were made to search for cathode materials which will tolerate a large amount of Ca-ions reversibly extracted/ re-accommodated upon charge/discharge. Material systems including Prussian blue compounds, [10,13,14] Chevrel phases, [15,16] spinels, [17][18][19] perovskites, [20] layered transition metal (TM) sulfides, [21] and iron phosphate, [22] were suggested to be effective Ca-ion electrodes with the spinels and perovskites attracting extra attention because of their predicted high voltage (>3.5 V) and large theoretical capacities (>240 mAh g −1 ) during discharge at room temperature. [17][18][19][20] Distinct from these TM-based electrodes, a graphite cathode has been reported which functions via the (de-)intercalation of electrolyte salt anions (A − = PF 6 − , ClO 4 − , and so on) upon charge/discharge at remarkably high voltages (4.5-5.6 V) [23,24] with a theoretical capacity as high as 372 mAh g −1 (corresponding to AC 6 ). [24,25] Yet, the practical capacity of batteries based on this material suffers from a large degradation (≈90 mAh g −1 ) as a result of the electrolyte decomposition under high voltage. [24] Unlike the continuous development of CIB cathode materials, studies focusing on anodes have been relatively scarce. Graphite-based CIB anodes have been shown to be problematic at room temperature due to difficulties related to the intercalation of calcium. [26] The pursuit of a calcium metal Ca-ion batteries (CIBs) show promise to achieve the high energy density required by emerging applications like electric vehicles because of their potentially improved capacities and high operating voltages. The development of CIBs is hindered by the failure of traditional graphite and calcium metal anodes due to the intercalation difficulty and the lack of efficient electrolytes. Recently, a high voltage (4.45 V) CIB cell using Sn as the anode has been reported...

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Enabling the high capacity of lithium-rich anti-fluorite lithium iron oxide by simultaneous anionic and cationic redox

Cited by 151 publications

References 41 publications

Fundamental Insights from a Single‐Crystal Sodium Iridate Battery

Fundamental Insights from a Single‐Crystal Sodium Iridate Battery

High Reversibility of Lattice Oxygen Redox Quantified by Direct Bulk Probes of Both Anionic and Cationic Redox Reactions

Discovery of Calcium‐Metal Alloy Anodes for Reversible Ca‐Ion Batteries

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