Controlled synthesis of dual-phase carbon-coated Nb2O5/TiNb2O7 porous spheres and their Li-ion storage properties

Yoon, Sukeun; Lee, Sung-Yun; Nguyen, Tuan Loi; Kim, Il Tae; Woo, Sang‐Gil; Cho, Kuk Young

doi:10.1016/j.jallcom.2017.10.051

Cited by 34 publications

(18 citation statements)

References 32 publications

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“…A capacity of 232.7 mA h g –1 would be expected on the basis of one-electron reductions of Ti 4+ to Ti 3+ and Nb 5+ to Nb 4+ (i.e., Li 3 TiNb 2 O 7 ), with additional capacity reported through multielectron redox or “overlithiation” beyond one lithium per transition metal (Li/TM). Previous studies have focused on aspects of the structural mechanism of lithiation in TiNb 2 O 7 ,, and performance-optimizing synthetic strategies. − ,,− In addition to the generic challenges associated with implementing nanostructured particles for energy storagecost, stability, and scalabilityTiNb 2 O 7 also specifically exhibits problematic gas evolution that is exacerbated by high-surface-area morphologies . In this work, we approach the fundamental aspects of electrochemical energy storage in TiNb 2 O 7 by studying the lithiation of low-surface-area, micrometer-scale particles.…”

Section: Introductionmentioning

confidence: 99%

Ionic and Electronic Conduction in TiNb₂O₇

et al. 2019

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TiNb2O7 is a Wadsley–Roth phase with a crystallographic shear structure and is a promising candidate for high-rate lithium ion energy storage. The fundamental aspects of the lithium insertion mechanism and conduction in TiNb2O7, however, are not well-characterized. Herein, experimental and computational insights are combined to understand the inherent properties of bulk TiNb2O7. The results show an increase in electronic conductivity of seven orders of magnitude upon lithiation and indicate that electrons exhibit both localized and delocalized character, with a maximum Curie constant and Li NMR paramagnetic shift near a composition of Li0.60TiNb2O7. Square-planar or distorted-five-coordinate lithium sites are calculated to invert between thermodynamic minima or transition states. Lithium diffusion in the single-redox region (i.e., x ≤ 3 in Li x TiNb2O7) is rapid with low activation barriers from NMR and D Li = 10–11 m2 s–1 at the temperature of the observed T 1 minima of 525–650 K for x ≥ 0.75. DFT calculations predict that ionic diffusion, like electronic conduction, is anisotropic with activation barriers for lithium hopping of 100–200 meV down the tunnels but ca. 700–1000 meV across the blocks. Lithium mobility is hindered in the multiredox region (i.e., x > 3 in Li x TiNb2O7), related to a transition from interstitial-mediated to vacancy-mediated diffusion. Overall, lithium insertion leads to effective n-type self-doping of TiNb2O7 and high-rate conduction, while ionic motion is eventually hindered at high lithiation. Transition-state searching with beyond Li chemistries (Na+, K+, Mg2+) in TiNb2O7 reveals high diffusion barriers of 1–3 eV, indicating that this structure is specifically suited to Li+ mobility.

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Section: Introductionmentioning

confidence: 99%

Ionic and Electronic Conduction in TiNb₂O₇

et al. 2019

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“…One of the most straightforward approaches to avoid Li plating is to adopt relatively high voltage anode materials, such as Li 4 Ti 5 O 12 (LTO), − TiO 2 , − and Ti x Nb 2 O 5+2 x , − which possess average lithiation potentials higher than 1.5 V vs Li/Li + . Although such high potentials reduce the energy density of the full cells as compared to those based on graphite anode, they can totally inhibit the formation of Li dendrites and solid electrolyte interphase (SEI) even under extreme high current densities. , Among all of the emerging high-voltage anode materials, TiNb 2 O 7 (TNO) has been considered as one of the most promising alternatives to replace graphite anode in practical LIBs. ,,− The Wadsley–Roth phase TNO possesses a high theoretical specific capacity of 387.6 mAh g –1 based on a total 5 Li-ions’ reaction within one Ti 4+ /Ti 3+ and two Nb 5+ /Nb 3+ redox couples in the TNO structural unit. , In addition, an exceptional theoretical volumetric capacity of 1680 mAh cm –3 can be achieved on the basis of a density of 4.34 g cm –3 of TNO, which is double that of conventional graphite anode .…”

Section: Introductionmentioning

confidence: 99%

Carbon Coated Porous Titanium Niobium Oxides as Anode Materials of Lithium-Ion Batteries for Extreme Fast Charge Applications

Lyu

Wang

et al. 2020

ACS Appl. Energy Mater.

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The development of electric vehicles (EVs) has been restricted by severe lithium plating in lithium-ion batteries (LIBs) with graphite as the anode. To mitigate the lithium plating issue, carbon coated porous titanium niobium oxides (TNO@C) have been synthesized and evaluated as anode materials for extreme fast charge (XFC) applications in LIBs. Various methods have been utilized to optimize the full cells with LiNi0.6Mn0.2Co0.2O2 (NMC) as the cathode and TNO@C as the anode, delivering a high energy density of 142.8 Wh/kg (357 Wh/L) and a good energy density retention over 80% after 500 cycles with a 10 min fast charging protocol. The interfacial behaviors of the TNO@C and NMC electrodes during XFC cycling have also been investigated, proving that the lithium plating problem can be effectively suppressed by the high-voltage TiNb2O7 anode even under XFC conditions. The high energy density and long cycling stability of the NMC/TNO@C full cells demonstrate that the TNO@C anode is a promising candidate to replace graphite anode in LIBs for fast charging EVs with long driving ranges.

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“…42 Small peaks at 1.7 V in the discharge process and 2.1 V in the charge process are related to additional Ti 4+ /Ti 3+ redox couples. 5,18,43,44 Figure 4D reveals the dQ/dV plot of the TNO/PGO composite, which is associated with each redox reaction appearing at the same position as that of pristine TNO. Even though the peaks of the TNO/PGO composite are shown as slightly broader than those of pristine TNO, due to a surface capacitive reaction of GO, the TNO reacts reversibly with Li + after the PGO composite process.…”

Section: Resultsmentioning

confidence: 99%

“…In case of pristine TNO in Figure C, two sharp peaks are observed at 1.68 V in the discharge process and 1.66 V in charging, which is assigned to the reduction/oxidation process of Nb 5+ /Nb 4+ . Small peaks at 1.7 V in the discharge process and 2.1 V in the charge process are related to additional Ti 4+ /Ti 3+ redox couples . Figure D reveals the dQ / dV plot of the TNO/PGO composite, which is associated with each redox reaction appearing at the same position as that of pristine TNO.…”

Section: Resultsmentioning

confidence: 99%

TiNb ₂ O ₇ microsphere anchored by polydopamine‐modified graphene oxide as a superior anode material in lithium‐ion batteries

2020

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Summary TiNb2O7 (TNO) is considered a promising anode material for lithium‐ion batteries. High contact and homogeneity of the composite fabricated by TNO powder and conductive materials with different density are significant to improve the poor electric conductivity of TNO microspheres. In this study, we introduce graphene oxide (GO) to synthesize a composite material with TNO microspheres. Moreover, a polydopamine (PDA) coating technique is applied to achieve uniform distribution and high contact between TNO and GO materials. The ‐OH catechol groups in the PDA have a strong adhesion ability to inorganic surfaces. After a simple sonication process, the hybrid material is well‐fabricated, where TNO microspheres are attached along the surface of the PDA‐coated GO (PGO). The TNO/PGO composite shows remarkably enhanced performances such as cycling stability (202.7 mAh g−1 over 300 cycles at 1C) and rate capability (136.5 mAh g−1 over 1000 cycles at 5C). The formation of a high conductive network among TNO microspheres mainly enhances those electrochemical performances, and the PDA layer is a key factor in obtaining a homogeneous GO composite through its high adhesive ability and hydrophilicity.

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Controlled synthesis of dual-phase carbon-coated Nb2O5/TiNb2O7 porous spheres and their Li-ion storage properties

Cited by 34 publications

References 32 publications

Ionic and Electronic Conduction in TiNb₂O₇

Ionic and Electronic Conduction in TiNb₂O₇

Carbon Coated Porous Titanium Niobium Oxides as Anode Materials of Lithium-Ion Batteries for Extreme Fast Charge Applications

TiNb ₂ O ₇ microsphere anchored by polydopamine‐modified graphene oxide as a superior anode material in lithium‐ion batteries

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Controlled synthesis of dual-phase carbon-coated Nb2O5/TiNb2O7 porous spheres and their Li-ion storage properties

Cited by 34 publications

References 32 publications

Ionic and Electronic Conduction in TiNb2O7

Ionic and Electronic Conduction in TiNb2O7

Carbon Coated Porous Titanium Niobium Oxides as Anode Materials of Lithium-Ion Batteries for Extreme Fast Charge Applications

TiNb 2 O 7 microsphere anchored by polydopamine‐modified graphene oxide as a superior anode material in lithium‐ion batteries

Contact Info

Product

Resources

About

Ionic and Electronic Conduction in TiNb₂O₇

Ionic and Electronic Conduction in TiNb₂O₇

TiNb ₂ O ₇ microsphere anchored by polydopamine‐modified graphene oxide as a superior anode material in lithium‐ion batteries