Li4Ti5O12 Nanoparticles Prepared with Gel‐hydrothermal Process as a High Performance Anode Material for Li‐ion Batteries

The use of the [Fe(III) (AA)(CN)4](-) complex anion as metalloligand towards the preformed [Cu(II) (valpn)Ln(III)](3+) or [Ni(II) (valpn)Ln(III) ](3+) heterometallic complex cations (AA=2,2'-bipyridine (bipy) and 1,10-phenathroline (phen); H2 valpn=1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu(II) (valpn)Ln(III) (H2O)3 (μ-NC)2 Fe(III) (phen)(CN)2 {(μ-NC)Fe(III) (phen)(CN)3}]NO3 ⋅7 H2O}n (Ln=Gd (1), Tb (2), and Dy (3)) and the trinuclear complex [Cu(II) (valpn)La(III) (OH2 )3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ]⋅NO3 ⋅H2O⋅CH3 CN (4) were obtained with the [Cu(II) (valpn)Ln(III)](3+) assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni(II) (valpn)Ln(III) (ONO2 )2 (H2 O)(μ-NC)3 Fe(III) (bipy)(CN)]⋅2 H2 O⋅2 CH3 CN}n (Ln=Gd (5), Tb (6), and Dy (7)) resulted with the related [Ni(II) (valpn)Ln(III) ](3+) precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu(II) (valpn)La(III) (OH2)3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ](+), nitrate counterions, and non-coordinate water and acetonitrile molecules. The heteroleptic {Fe(III) (bipy)(CN)4} moiety in 5-7 acts as a tris-monodentate ligand towards three {Ni(II) (valpn)Ln(III)} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu(II)-Ln(III) (1-3) and Ni(II)-Ln(III) (5-7) units, as well as through the single cyanide bridge between the Fe(III) and either Ni(II) (5-7) or Cu(II) (4) account for the overall ferromagnetic behavior observed in 1-7. DFT-type calculations were performed to substantiate the magnetic interactions in 1, 4, and 5. Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out-of-phase ac signals below 4.0 K in the lack of a dc field, the values of the pre-exponential factor (τo) and energy barrier (Ea ) through the Arrhenius equation being 2.0×10(-12) s and 29.1 cm(-1), respectively. In the case of 7, the ferromagnetic interactions through the double phenoxo (Ni(II)-Dy(III)) and single cyanide (Fe(III)-Ni(II)) pathways are masked by the depopulation of the Stark levels of the Dy(III) ion, this feature most likely accounting for the continuous decrease of χMT upon cooling observed for this last compound.

show abstract

“…Synthesis of LTO Nanoparticles (Nano‐LTO) : Nano‐LTO was prepared according to a procedure previously reported 57…”

Section: Methodsmentioning

confidence: 99%

Heterotrimetallic Coordination Polymers: {Cu^IILn^IIIFe^III} Chains and {Ni^IILn^IIIFe^III} Layers: Synthesis, Crystal Structures, and Magnetic Properties

Alexandru

Visinescu

Andruh

et al. 2015

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…In ref 18, NMR was used to determine that lithium partly occupies the 16c position at room temperature, in contrast to the observations of the present study. Other studies show that the crystallinity of the Li 4 Ti 5 O 12 samples strongly depends on the annealing temperature 37 and that the electrochemical intercalation of more than three Li þ ions in nanoparticulate Li 4 Ti 5 O 12 samples is possible. 11 This suggests that the particle size as well as the synthesis conditions influences the crystal structure, and probably also the ionic conductivity and lithium migration in Li 4 Ti 5 O 12 .…”

Section: Neutron Diffraction Measurements Upon Heating Andmentioning

confidence: 99%

Lithium Migration at High Temperatures in Li₄Ti₅O₁₂ Studied by Neutron Diffraction

Laumann¹,

Boysen²,

Bremholm

et al. 2011

Chem. Mater.

View full text Add to dashboard Cite

The structure of Li 4 Ti 5 O 12 was investigated by neutron powder diffraction, and the study revealed unprecedented details about lithium migration at high temperatures. A commercial sample of the battery anode material Li 4 Ti 5 O 12 (spinel-type) was measured from room temperature to 1100 °C. Up to 500 °C, linearly increasing values for the unit cell parameter, the isotropic atomic displacement parameters, and the oxygen position are observed. At 700 °C, a change of slope occurs, which is assigned to the beginning migration of lithium. Previous investigations identified the octahedral 16c site in the spinel structure as the migration position of lithium upon heating to high temperatures, and because of that, several phase transitions of Li 4 Ti 5 O 12 at high temperatures have been proposed. Here, we unambiguously identify that the lithium atoms occupy split sites around the 16c positions and orderÀdisorder phase transitions of Li 4 Ti 5 O 12 were not observed. One-particle potential shows that the occupancy of 16c is an unstable configuration and that the split-site structure leads to a more favorable migration position. Occupation of the lithium sites (32e) results in the same long-range diffusion path in all AE110ae directions. The onset of lithium migration can explain the change of the ionic conductivity of Li 4 Ti 5 O 12 at high temperatures, which has been observed by impedance spectroscopic studies. Further heating to 1000 °C resulted in a partial decomposition of Li 4 Ti 5 O 12 into the ramsdellite-type Li 2 Ti 3 O 7 and the cubic γ-Li 2 TiO 3 , and at 1100 °C, the Li 4 Ti 5 O 12 spinel was fully decomposed.

show abstract

“…In practical applications, the cut-off voltage of Li 4 Ti 5 O 12 is 1 V (vs Li + /Li), which is much higher than the reduction potential of electrolyte solvents. , The high cut-off voltage of Li 4 Ti 5 O 12 avoids the formation of the solid electrolyte interface (SEI), which is beneficial to fast surface ion transportation and high rate performances . Furthermore, Li 4 Ti 5 O 12 is known as a zero-strain insertion material and owns negligible volume expansion during cycles . Therefore, Li 4 Ti 5 O 12 can exhibit a long cycle life, prospective power capability, and low security risks.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional and Mesopore-Oriented Graphene Conductive Framework Anchored with Nano-Li₄Ti₅O₁₂ Particles as an Ultrahigh Rate Anode for Lithium-Ion Batteries

Xiang

Zhao

Jin

et al. 2018

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Because of the disadvantages of commercial graphite anodes for high-power lithium-ion batteries, a kind of spinel nanolithium titanate (Li 4 Ti 5 O 12 )/graphene microsphere composite [denoted as LTO/reduced graphene oxide (rGO)] is successfully synthesized. The as-prepared composite is made up of curled graphene sheets which are anchored with nano-Li 4 Ti 5 O 12 particles. These nano-Li 4 Ti 5 O 12 particles are uniformly decorated on the conductive graphene framework and their sizes range from just 15 to 20 nm. In the asprepared composite, the curled graphene sheets form a unique mesopore-oriented structure which provides plenty of threedimensional channels for ion transportation. These structure characters greatly improve both the electron conductivity and Li + diffusion ability. The ratio of pseudocapacitive capacity dramatically increases in the obtained LTO/rGO composite and generates excellent ultrahigh rate performances. The as-prepared LTO/rGO composite delivers a reversible capacity of 70.3 mA h g −1 at 200 C and a capacity retention of 84.7% after 1000 cycles at 50 C. As the current density varies from 30 to 100 C, the special capacity remains unchanged (about 112 mA h g −1 ). These results show that the graphene framework-supported nano-Li 4 Ti 5 O 12 composite has potential application in high-power lithium-ion batteries.

show abstract

Li₄Ti₅O₁₂ Nanoparticles Prepared with Gel‐hydrothermal Process as a High Performance Anode Material for Li‐ion Batteries

Cited by 14 publications

References 23 publications

Heterotrimetallic Coordination Polymers: {Cu^IILn^IIIFe^III} Chains and {Ni^IILn^IIIFe^III} Layers: Synthesis, Crystal Structures, and Magnetic Properties

Heterotrimetallic Coordination Polymers: {Cu^IILn^IIIFe^III} Chains and {Ni^IILn^IIIFe^III} Layers: Synthesis, Crystal Structures, and Magnetic Properties

Lithium Migration at High Temperatures in Li₄Ti₅O₁₂ Studied by Neutron Diffraction

Three-Dimensional and Mesopore-Oriented Graphene Conductive Framework Anchored with Nano-Li₄Ti₅O₁₂ Particles as an Ultrahigh Rate Anode for Lithium-Ion Batteries

Contact Info

Product

Resources

About

Li4Ti5O12 Nanoparticles Prepared with Gel‐hydrothermal Process as a High Performance Anode Material for Li‐ion Batteries

Cited by 14 publications

References 23 publications

Heterotrimetallic Coordination Polymers: {CuIILnIIIFeIII} Chains and {NiIILnIIIFeIII} Layers: Synthesis, Crystal Structures, and Magnetic Properties

Heterotrimetallic Coordination Polymers: {CuIILnIIIFeIII} Chains and {NiIILnIIIFeIII} Layers: Synthesis, Crystal Structures, and Magnetic Properties

Lithium Migration at High Temperatures in Li4Ti5O12 Studied by Neutron Diffraction

Three-Dimensional and Mesopore-Oriented Graphene Conductive Framework Anchored with Nano-Li4Ti5O12 Particles as an Ultrahigh Rate Anode for Lithium-Ion Batteries

Contact Info

Product

Resources

About

Li₄Ti₅O₁₂ Nanoparticles Prepared with Gel‐hydrothermal Process as a High Performance Anode Material for Li‐ion Batteries

Heterotrimetallic Coordination Polymers: {Cu^IILn^IIIFe^III} Chains and {Ni^IILn^IIIFe^III} Layers: Synthesis, Crystal Structures, and Magnetic Properties

Heterotrimetallic Coordination Polymers: {Cu^IILn^IIIFe^III} Chains and {Ni^IILn^IIIFe^III} Layers: Synthesis, Crystal Structures, and Magnetic Properties

Lithium Migration at High Temperatures in Li₄Ti₅O₁₂ Studied by Neutron Diffraction

Three-Dimensional and Mesopore-Oriented Graphene Conductive Framework Anchored with Nano-Li₄Ti₅O₁₂ Particles as an Ultrahigh Rate Anode for Lithium-Ion Batteries