Structure, surface and broadband impedance spectroscopy of Li4Ti5O12 based ceramics with Nb and Ta

Орлюкас, А.Ф.; Fung, Kuan‐Zong; Venckutė, V.; Kazlauskienė, V.; Miškinis, J.; Lelis, Martynas

doi:10.1016/j.ssi.2014.09.037

Cited by 13 publications

(8 citation statements)

References 18 publications

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“…Computational method : The ab initio calculations were performed in the density functional theory (DFT) framework as implemented in the Vienna ab initio Simulation Package (VASP), using generalized gradient approximation (GGA) parameterized by Perdew–Burke–Ernzerhof (PBE) . The projector augmented wave (PAW) method with a plane wave cutoff of 600 eV was used .…”

Section: Methodsmentioning

confidence: 99%

One‐Step Synthesis of Highly Oxygen‐Deficient Lithium Titanate Oxide with Conformal Amorphous Carbon Coating as Anode Material for Lithium Ion Batteries

Nasara

Tsai

Lin

2017

Adv Materials Inter

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incorporation of conductive agents, [9][10][11] doping of metal ions, [12][13][14] and nanonization, that is, reduction in particle size. [15,16] Although all of these methods yielded notable results, our proposed alternative synthesis is greatly on-par, in addition to being a one-pot, facile, and inexpensive process which requires no additional precursors and processing-a very favorable route with manufacturing considerations.Chiang and co-workers summarized available electronic conductivity data for LTO, in which the defective-LTO (with oxygen vacancies) was of the highest reported electronic conductivity. [17] Therefore, it has gotten great interest and numerous researchers had engineered processes to generate oxygen vacancies in the LTO structure. [18][19][20] With amorphous carbon coating, Chen and co-workers demonstrated lower Li ion (Li + ) interfacial transfer resistance which dramatically enhanced the battery performance. [21] Altogether achieving a "double" effect, Wang et al. introduced nanosized LTO with surface modifications of Ti (III) and carbon with improved surface conductivity and restricted particle growth due to the carbonization of polyaniline (PANI); [22] however, they were not able to maximize the effects of oxygen vacancies by generating a low level; and their nonuniform carbon layers can possibly impede Li + transport, especially when graphitized. [23] Finally, the importance of these modifications in relation to the Li + interfacial charge-transfer resistance was not highlighted in the aforementioned studies.Herein, we propose a one-pot, facile, and extremely inexpensive strategy by using conventional solid-state precursors of lithium carbonate (Li 2 CO 3 ) and titanium oxide (TiO 2 ) in an ethanol solution, through which a high level of oxygen vacancies and conformal amorphous carbon coating were simultaneously achieved. The formation mechanism of the one-pot synthesized, highly oxygen-deficient, and amorphous-carbon-coated LTO, as well as the origin of its superior electrochemical properties, are elaborated with the aid of the ab initio calculation. The enhanced interfacial electrochemical properties as well as the stabilization of highly oxygen-deficient structure are attributed to the conformal amorphous carbon. The dramatic reduction of overall resistance was in the Li + interfacial charge transfer, which sheds light to an emerging importance of interfacial modification, is highlighted in this paper.The lithium titanate defect spinel, Li 4 Ti 5 O 12 (LTO), is a promising "zero-strain" anode material for lithium-ion batteries in cycling-demanding applications. However, the low-rate capability limits its range of applications. Surface modifications, for example, coating and defect engineering, play an intriguing role in interfacial electrochemical processes. Herein, a novel synthesis of highly oxygen-deficient "defective-LTO" anode material with highrate performance is reported. It is synthesized using conventional precursors via a one-pot thermal reduction process. A high level of ox...

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Section: Methodsmentioning

confidence: 99%

One‐Step Synthesis of Highly Oxygen‐Deficient Lithium Titanate Oxide with Conformal Amorphous Carbon Coating as Anode Material for Lithium Ion Batteries

Nasara

Tsai

Lin

2017

Adv Materials Inter

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“…The common dopants in Li + sites include Na + , [80][81][82] K + , [82,83] Mg 2+ , [84] Ca 2+ , [85] Zn 2+ , [86] Cu 2+[87] and La 3+ , [88] including Fe 3+ , [89] Co 3+ , [90] Ni 3+ , [91] Al 3+ , [92][93][94] Cr 3+ , [91,95] La 3+ , [96] Pr 3+ , [97] Bi 3+ , [98] Sc 3+ , [99] Eu 2+/3+ , [100] Sm 3+ , [101] Gd 3+ , [102] Ti 3+ , [103] Mo 4+ , [104] Mn 4+ , [105] Ce 3+/4+ , [106] Sn 4+ , [107] Zr 4+ , [93,[108][109][110] Si 4+ , [109] V 5+ , [111,112] Ta 5+ , [113,114] Sb 5+ , [115] Nb 5+ [114,116] and W 6+ , [117] etc. The role of doping in Li 4 Ti 5 O 12 is thought to be based on the defect equilibrium that Ti 4+ in the octahedral 16d site of spinel lattice can be reduced to Ti 3+ by the aliovalent dopant, thereby intrinsically increasing the electron concentration of Li 4 Ti 5 O 12 bulk.…”

Section: Element Dopingmentioning

confidence: 99%

“…Take Mo 4+ for example: the substitution of Ti 4+ with Mo 4+ tends to improve the electronic conductivity by reducing the bandgap of the electronic structure. [111][112][113][114]116,117] However, high valence-state cation substitutions may also lead to the formation of a Li + vacancy or a Ti 4+ vacancy. [124] Moreover, high valence state dopant ions, such as V 5+ , Ta 5+ , Nb 5+ , W 6+ , etc., entering octahedral 16d Ti 4+ sites may improve the electronic conductivity by increasing the electron concentration through the formation of Ti 3+ .…”

Section: Element Dopingmentioning

confidence: 99%

“…The common dopants in Li + sites include Na + , K + , Mg 2+ , Ca 2+ , Zn 2+ , Cu 2+ and La 3+ , etc. ; a lot of dopants have been reported in Ti 4+ sites, including Fe 3+ , Co 3+ , Ni 3+ , Al 3+ , Cr 3+ , La 3+ , Pr 3+ , Bi 3+ , Sc 3+ , Eu 2+/3+ , Sm 3+ , Gd 3+ , Ti 3+ , Mo 4+ , Mn 4+ , Ce 3+/4+ , Sn 4+ , Zr 4+ , Si 4+ , V 5+ , Ta 5+ , Sb 5+ , Nb 5+ and W 6+ , etc. ; the dopants in O sites include F and Br .…”

Section: Approaches To Improving Rate Performance and Specific Capacitymentioning

confidence: 99%

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Challenges of Spinel Li₄Ti₅O₁₂ for Lithium‐Ion Battery Industrial Applications

Yuan

Tan

et al. 2017

Advanced Energy Materials

348

233

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“…The electrical conductivity of carbon and its distribution can also severely influence the electrochemical stability of a composite electrode as we have demonstrated recently . LTO doping (e. g., with Cu 2+ , Mg 2+ , Zn 2+ , Fe 3+ , Cr 3+ , Al 3+ , Sn 4+ , Zr 4+ , Ta 5+ , V 5+ , Nb 5+ , W 6+ ) is another effective way to improve the intrinsic electronic conductivity of LTO. Such doping elements have been reported to reduce a fraction of Ti 4+ into Ti 3+ and hence increase the overall electron concentration .…”

Section: Introductionmentioning

confidence: 97%

Valence‐Tuned Lithium Titanate Nanopowder for High‐Rate Electrochemical Energy Storage

Widmaier

Pfeifer

Bommer

et al. 2018

Batteries & Supercaps

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In recent years, numerous studies have explored ways to overcome the low intrinsic electrical conductivity of lithium titanate (Li 4 Ti 5 O 12 , LTO) for energy storage with lithium-ion batteries. These approaches almost exclusively considered element doping and elaborate LTO-carbon nanocomposites, whereas simple adjustment of the defect concentration remains largely unexplored. In our study, we tune the Ti 3 + /Ti 4 + concentration of a commercial LTO nanopowder through oxygen vacancy formation during thermal annealing in hydrogen atmosphere. We investigate the impact of the treatment on material properties like energy band structure, electrical conductivity, crystallinity, phase distribution, surface chemistry, and particle morphology, and correlate these parameters to the electrochemical performance. At optimum treatment conditions, the intrinsic electrical conductivity can be greatly improved, while circumventing LTO phase transformations or amorphization. This enables the reduction of the carbon concentration to 5 mass%, while yielding a high electrode capacity of about 70 mAh/g (82 mAh/g based on active mass) at ultrahigh C-rates of 100C. When combined with an activated carbon/lithium manganese oxide composite cathode, an excellent energy and power performance of 70 Wh/kg and 47 kW/ kg were obtained (82 Wh/kg and 55 kW/kg based on active mass), while maintaining 83 % of its energy ratings after 5000 cycles at 10C (78 % after 15000 cycles at 100C).often neglected when calculating the capacity (i. e., capacity is only normalized to the LTO mass of the electrode). Yet, such a normalization is questionable as the electrode may contain up to 20-50 mass% carbon and only the performance of the entire electrode is of importance for an actual device (not how well a small quantity of LTO performs in a massive matrix of electrochemically inactive carbon).The electrical conductivity of carbon and its distribution can also severely influence the electrochemical stability of a composite electrode as we have demonstrated recently. [14] LTO doping (e. g., with Cu 2 + , [41] Mg 2 + , [42] Zn 2 + , [43] Fe 3 + , [44] Cr 3 + , [45] Al 3 + , [46] Sn 4 + , [47] Zr 4 + , [48] Ta 5 + , [49] V 5 + , [50] Nb 5 + , [51] W 6 + [52] ) is another effective way to improve the intrinsic electronic conductivity of LTO. Such doping elements have been reported to reduce a fraction of Ti 4 + into Ti 3 + and hence increase the overall electron concentration. [53] Nevertheless, element doping might entail additional problems related to the toxicity of certain doping elements and possible detrimental side reactions. [54] In 2006, Wolfenstine et al. [55] discovered that Ti 3 + valence states may form during prolonged annealing (36 h) of LTO at 800 8C in hydrogen containing atmosphere, although the root cause of this effect remained unknown. This simple strategy is free of waste products and does not require the addition of any other additional chemicals or catalysts, [56] but has only attracted little attention in literature so far (especially i...

show abstract

Structure, surface and broadband impedance spectroscopy of Li4Ti5O12 based ceramics with Nb and Ta

Cited by 13 publications

References 18 publications

One‐Step Synthesis of Highly Oxygen‐Deficient Lithium Titanate Oxide with Conformal Amorphous Carbon Coating as Anode Material for Lithium Ion Batteries

One‐Step Synthesis of Highly Oxygen‐Deficient Lithium Titanate Oxide with Conformal Amorphous Carbon Coating as Anode Material for Lithium Ion Batteries

Challenges of Spinel Li₄Ti₅O₁₂ for Lithium‐Ion Battery Industrial Applications

Valence‐Tuned Lithium Titanate Nanopowder for High‐Rate Electrochemical Energy Storage

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Structure, surface and broadband impedance spectroscopy of Li4Ti5O12 based ceramics with Nb and Ta

Cited by 13 publications

References 18 publications

One‐Step Synthesis of Highly Oxygen‐Deficient Lithium Titanate Oxide with Conformal Amorphous Carbon Coating as Anode Material for Lithium Ion Batteries

One‐Step Synthesis of Highly Oxygen‐Deficient Lithium Titanate Oxide with Conformal Amorphous Carbon Coating as Anode Material for Lithium Ion Batteries

Challenges of Spinel Li4Ti5O12 for Lithium‐Ion Battery Industrial Applications

Valence‐Tuned Lithium Titanate Nanopowder for High‐Rate Electrochemical Energy Storage

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Product

Resources

About

Challenges of Spinel Li₄Ti₅O₁₂ for Lithium‐Ion Battery Industrial Applications