Lithium Titanium Oxide Research Articles

Synthesis and structural properties of lithium titanium oxide powder as-synthesized by two step calcination process

A two-step calcination synthesis, considering the potential for mass production, of lithium titanium oxide powder was carried out to fabricate a single Li4Ti5O12 phase, which is useful for anode electrode material of Li-based rechargeable battery as well as an electrode for supercapacitor. The final composition is controlled by adding more TiO2 powder into powder gained at one calcination process during the two calcination process. We investigated the influence of excess TiO2 on the structural characteristics of lithium titanium oxide synthesized by the two-step calcination method. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) measurements showed that the as-synthesized powder had a spinel crystal structure as well as A composition of 4: 5: 12. In addition, a high resolution transmission electron microscopy (HRTEM) analysis revealed that the fabricated powder exhibited a single crystalline phase formation. These results indicated that the powder synthesized in the one-step calcination process showed coexistence crystalline phases, which are the Li4Ti5O12 and Li2.39Ti3.4O8 phase. However, in the two-step calcination process, the powder synthesized showed the single crystalline Li4Ti5O12 phase. A very uniform grain size of the as-synthesized powder was shown in a field emission scanning electron microscopy (FESEM). These results suggested that the two-step calcination process can be used for synthesis of single crystalline Li4Ti5O12 powder with uniform grain shape and provide motivation to pursue mass production of lithium titanium based oxide powder for bulk type batteries.

Electrochemical Kinetics and Safety of 2-Volt Class Li-Ion Battery System Using Lithium Titanium Oxide Anode

Microvoltammograms of a single particle of lithium titanium oxide (LTO, ) spinel were interpreted using a core-shell model in the spinel∕rock-salt two-phase transition process. Lithium insertion into the particle was controlled by the diffusion in LTO rock-salt structure outlayer. The quick charging was effectively enhanced by reducing the LTO particle size. Lithium extraction from the particle was significantly affected by the charge transfer on the LTO spinel outlayer rather than by the diffusion of lithium ions. The discharge speed during the internal short-circuit abuse test connecting with the LTO anode was 3 orders of magnitude slower than that with graphite anode. At the internal short-circuit point, transformation to the low electron-conductive LTO spinel phase will work to suppress the rapid extension of internal short circuit reaction. A class lithium-ion battery system using the LTO anode had a high output and input power density of for a pulse condition. Quick-charging performance showed 80% of the full capacity in . It was demonstrated that the class lithium-ion battery system exhibited excellent high power and quick charging with outstanding safety characteristics by using the LTO anode.

Electrochemical and Thermal Characterization of Surface on Lithium Titanium Oxide in Electrolytes

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Long Life Lithium-Ion Cells at Elevated Temperature of 80 oC Using Lithium Titanium Oxide Negative Electrode with Solid Electrolyte Interface

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Three-volt Lithium-ion Battery Consisting of Li[Ni1/2Mn3/2]O4 and Li[Li1/3Ti5/3]O4: Improvement of Positive-electrode Material for Long-life Medium-power Applications

A long-life medium-power three-volt lithium-ion battery consisting of Li[Ni1/2Mn3/2]O4 (P4332) and the zero-strain lithium insertion material of lithium titanium oxide (LTO; Li[Li1/3Ti5/3]O4) was described with emphasis on the processing method to prepare Li[Ni1/2Mn3/2]O4 for long-life applications. The preparation conditions were re-examined by thermogravimetric analysis, scanning electron microscopy, FT-IR, powder X-ray diffraction, and electrochemical methods. Well-defined crystals having the (111) facets of octahedra are essential for long-life application, which can be made by heating a reaction mixture at a temperature higher than 900°C in air for 12 h, and characteristic absorption bands of the superlattice structure in IR spectra were also needed for both a high rechargeable capacity more than 135 mAh g−1 with a flat operating voltage and long cycle life, which can be made by heating the well-defined crystals at 700°C in air for at least 12 h, i.e., two-step solid-state reaction. To demonstrate the long-life medium-power three-volt lithium-ion battery, the 2000-cycle test of the cell under a positive-electrode-limited capacity was performed at 3.33 mA cm−2 or 259 mA g−1 based on the Li[Ni1/2Mn3/2]O4 weight from 1.0 to 3.5 V at room temperature. Based on the results, no noticeable increase in polarization was observed even after 2000 cycles although the capacity faded ca. 15%. The unexpected capacity fading is described in terms of an imbalance in the coulombic efficiencies associated with the complex chemistry at positive and negative electrodes by the electrolyte.

Steady-state polarization measurements of lithium insertion electrodes for high-power lithium-ion batteries

Steady-state polarization measurements of lithium titanium oxide (LTO; Li[Li1/3Ti5/3]O4) were carried out using the 0-V lithium-ion cells consisting of two identical LTO-electrodes with a parallel-plate symmetrical electrode configuration. The sinusoidal voltage with the peak amplitude of 1.0 V was imposed at 0.1 Hz upon the 0-V cells and the current response was measured as a function of time. The steady-state polarization, obtained by plotting the current versus applied voltage, was linear in current up to approximately 60 mA cm−2 or 4 A g−1 based on the LTO weight and suggested the resistance polarization only for the lithium insertion electrode of the LTO. The method was also applied to lithium aluminum manganese oxide (LAMO; Li[Li0.1Al0.1Mn1.8]O4) and the resistance polarization of the LAMO-electrode was determined for currents up to approximately 25 mA cm−2 or 2 A g−1 based on the LAMO weight. The validity of the results was examined for the polarization measurements of the 2.5-V lithium-ion battery consisting of LTO and LAMO, and the significance of the polarization measurements of lithium insertion electrodes for high-power applications was discussed.

Olivine-type nanoparticle for hybrid supercapacitors

LiCoPO4 nanoparticles were precipitated from polyethylene glycol solution of lithium acetate, cobalt acetate, and ammonium dihydrogen phosphate by refluxing at 250 °C for 35 h. The resultant powder samples were heated at 800 °C for different time periods of 2 and 4 h to study the effect of annealing time on the growth of samples. The X-ray diffraction pattern of the obtained samples exhibited olivine phase. The scanning electron microscopic images of dried powder sample and samples heated at 800 °C for 2 and 4 h showed a homogenous orthorhombic morphology with a particle size of few nanometers range. For the first time, orthorhombic olivine was introduced as positive electrode for a hybrid electrochemical supercapacitor cell with carbon nanofoam as negative electrode in 1 M LiClO4 in ethylene carbonate and propylene carbonate (1:1 in volume) solution. A sloping voltage profile of 2 to 0 V is observed for all the three hybrid cells. From the impedance results, we inferred that LiCoPO4 nanoparticles synthesized by polyol process offers less resistance than lithium titanium oxide. According to the results of electrochemical testing for the first time, maximum power density of 192 W/kg at 11 Wh/kg energy density was obtained for LiCoPO4 nanoparticles annealed at 800 °C for 2 h. The dried sample and the sample heated at 800 °C for 2 and 4 h exhibited high capacitances of 5, 19, and 4 F/g, respectively, with an excellent rate capability over 1,000 cycles.

Synthesis and Electrochemical Characterization of Spinel Lithium Titanium Cxide as Anode Material for Lithium Secondary Battery by sol-gel Method

Anode material lithium titanium oxide (Li4Ti5O12) for lithium- ion batteries was prepared by novel sol-gel method and by high energy ball milling (HEBM). Li4Ti5O12 based spinel-framework structures are of great interest material for lithium-ion batteries. X-ray diffraction (XRD) data show that powders grown with a spinel structure have been obtained at 850{degree sign}C for 5h. Scanning electron microscopy (SEM) analysis, show that uniformly distributed Li4Ti5O12 particles with grain sizes of 100nm are abtained. Lithium cells, consisting of Li4Ti5O12 as working electrode, lithium foil as both counter and reference electrodes showed the 280 mAh/g in the range of 0.0 ~ 3.0 V. Furthermore, the crystalline structure of Li4Ti5O12 didn't transform during the lithium intercalation and deintercalation process.

Solvothermal synthesis and electrochemical characterization of amorphous lithium titanate materials

Lithium titanate materials used for anode in Li-ion batteries were solvothermally synthesized from tetrabutyl titanate and LiOH at 140 °C. The synthesized powders show mainly amorphous state with a little amount of crystalline phase. The synthesized powders are a mixture composed of lithium titanium oxide and a complex compound (CH 3(CH 2) 3O) 4− x Ti(OLi) x . Sample with Li/Ti = 1.0 shows larger particle size and relatively good crystallinity compared to sample with Li/Ti = 0.8. Both of them display excellent cycleability with reversible capacity of ca. 85 mA/g at current density of 175 mA/g. When charged and discharged at 525 mA/g, the former keeps a good cycling stability, however, the later exhibits rapid capacity degradation. The relatively good crystallinity is certainly favorable to the structure stability and thus the cycling stability of electrode. Despite the low specific capacity of the synthesized lithium titanate material, the excellent cycling stability at high current density will make it a promising candidate for electrode material used in high power Li-ion batteries or capacitors.

Recent advances in liquid and polymer lithium-ion batteries

New types of electrode and electrolyte materials have been investigated and characterized in our laboratory. These include high capacity lithium–tin alloys, high-rate lithium titanium oxide and high conductivity gel-type, polymer electrolytes. The results obtained, collected in this article, demonstrate that these materials may be combined for the development of new types of liquid and polymer lithium-ion batteries having impressive features in terms of capacity, stability, high rates and, particularly, safety. Taking this into consideration, these batteries appear suitable power sources for electric or hybrid vehicles.

Synthesis and structural properties of lithium titanium oxide powder

Recently, lithium titanium oxide material has gained renewed interest in electrodes for lithium ion rechargeable batteries. We investigated the influence of excess Li on the structural characteristics of lithium titanium oxide synthesized by the conventional powder calcination method, considering the potential for mass production. The lithium excess ratio is controlled by using different weight of Li2CO3 powder during calcination. X-ray diffraction (XRD) measurement for the synthesized powder showed that the lithium titanium oxide material with excess lithium content had a spinel crystal structure as well as a different crystal one. In addition, high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) measurement revealed that the lithium titanium oxide powders with a lithium excess ratio of 5–20% exhibited a two phase formation. Inductively coupled plasma — atomic emission spectrometer (ICP-AES) and energy dispersive x-ray spectroscopy (EDX) measurements were used to analyze composition of the lithium titanium oxide powder. These results suggested that the conventional calcination method, considering the potential for mass production, formed two phases according to the Li excess amount in initial raw materials.

Lead-free Accumulators for Renewable and Clean Energy Technologies

Abstract Lead-free accumulators consisting of lithium aluminum manganese oxide (LAMO) and lithium titanium oxide (LTO) having spinel-framework structures are examined in 1 M LiBF4 acetonitrile. Results on zero-volt storage for 2 weeks, cycle tests at 1 mA cm−2 in voltages of 0 to 2.9 V for 20 cycles and then at 2 mA cm−2 in voltages of 2.0 to 2.9 V for 100 cycles, and rate-capability tests ranging from 0.3 to 16.7 mA cm−2 are presented and 12 V lead-free accumulators, in which 5 cells are connected in series, are proposed for renewable and clean energy technologies.

Nanosized Li4Ti5O12 Prepared by Molten Salt Method as an Electrode Material for Hybrid Electrochemical Supercapacitors

Nanosized lithium titanium oxide powder has been prepared using as a high-temperature flux. X-ray diffraction, scanning electron microscope, and transmission electron microscope measurements indicate that the obtained particles are uniform and the particle size of powder can be controlled by flux content and heating time. Under the optimal synthetic condition, the particle-size distribution is narrow . The hybrid electrochemical supercapacitors using a nanosized negative electrode in combination with an activated carbon positive electrode show much better rate capability than those based on the conventional prepared by solid-state reaction.

Analysis on the Structure of Lithium Titanium Oxide Due to Lithium Ratio 5% to 20% by Neutron Powder Diffraction with Rietveld Method

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A Structural Properties of Lithium Titanium Oxide have a Different Colors Due to Oxygen Excess Ratio by Neutron Powder Diffraction with Rietveld Method

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리튬이차전지 음극재용 나노입자 Li4Ti5O12의 전기화학적 연구

리튬이온전지용 음극 활물질로 스피넬 구조의 리튬 티탄산화물<TEX>$(Li_4Ti_5O_{12})$</TEX>이 졸겔법과 HEBM법으로 제조되었다. 제조된 <TEX>$Li_4Ti_5O_{12}$</TEX>의 입자크기 및 결정구조를 확인하기 위하여 X-선 회절분석(XRD), 주사전자현미경(SEM) 및 평균입자분석(PSA)을 수행한 결과 100nm의 균일한 크기의 입자를 확인하였다. 작업전극으로 <TEX>$Li_4Ti_5O_{12}$</TEX>를 사용하고 기준전극과 상대전극으로 lithium 호일을 사용하여 전기화학적인 삼상전극 셀을 구성하여 전기화학적인 특성 평가를 한 결과 <TEX>$1.0\sim2.5V$</TEX>의 전압 범위에서 고율 충 방전 성능과 0.2C에서 173mAh/g의 용량 특성을 나타내었다. <TEX>$Li_4Ti_5O_{12}$</TEX>은 리튬의 삽입과 탈리가 일어나는 동안 구조적인 안정성을 보여주고 있다. Lithium titanium oxide <TEX>$(Li_4Ti_5O_{12})$</TEX> with spinel-framework structures as anode material for lithium-ion battery was prepared by sol-gel and high energy ball milling (HEBH) method. According to the X-ray diffraction (XRD), Particle Size Analyses(PSA) and scanning electron microscopy (SEM) analysis, uniformly distributed <TEX>$Li_4Ti_5O_{12}$</TEX> particles with grain sizes of 100 nm were observed. Half cells, consisting of <TEX>$Li_4Ti_5O_{12}$</TEX> as working electrode and lithium foil as both counter and reference electrodes showed the high performance of high rate discharge capacity and 173 mAh/g at 0.2C in the range of <TEX>$1.0\sim2.5 V$</TEX>. Furthermore, the crystalline structure of <TEX>$Li_4Ti_5O_{12}$</TEX> didn't transform during the lithium intercalation and deintercalation process.

Comparative study of Li[CrTi]O 4, Li[Li 1/3Ti 5/3]O 4 and Li 1/2Fe 1/2[Li 1/2Fe 1/2Ti]O 4 in non-aqueous lithium cells

Comparative study of Li[CrTi]O 4, Li[Li 1/3Ti 5/3]O 4 and Li 1/2Fe 1/2[Li 1/2Fe 1/2Ti]O 4 was carried out in order to understand zero-strain insertion mechanism. Degree of defect defined by the occupation of lithium ions at 16(d) sites in Fd 3 ¯ m is 0% in Li[CrTi]O 4, 17% in Li[Li 1/3Ti 5/3]O 4 and 25% in Li 1/2Fe 1/2[Li 1/2Fe 1/2Ti]O 4. Electrochemical tests in non-aqueous lithium cells indicated that no fatal damage was observed with respect to XRD even for 25% defect of spinel-framework structure based on lithium titanium oxides. All samples examined here show the character of so-called zero-strain lithium insertion materials while Li 1/2Fe 1/2[Li 1/2Fe 1/2Ti]O 4 is converted to a rock-salt structure of Li 3/2Fe 1/2[Li 1/2Fe 1/2Ti]O 4 in which Fe 3+ ions at the tetrahedral sites move to the octahedral sites by changing oxidation state on reduction. FT-IR and Raman spectral measurements were also carried out and the factors affecting zero-strain insertion mechanism were discussed.

Combinatorial approach for powder preparation of pseudo-ternary system LiO 0.5–X–TiO 2 (X: FeO 1.5, CrO 1.5 and NiO)

Pseudo-ternary compounds of LiO 0.5–X–TiO 2 (X: FeO 1.5, CrO 1.5 and NiO) system were prepared using a fully automatic combinatorial robot system with the following functions: weighing and mixing of starting materials, heat treatment, and X-ray diffraction analysis. The following crystal structures were obtained by means of heat treatment at 1373 K: ramsdellite, spinel, pseudobrookite, rock salt, hematite and rutile. Furthermore, the composition range of the products with a ramsdellite-type structure in LiO 0.5–X–TiO 2 (X: FeO 1.5, CrO 1.5 and NiO) system was considered to have a relationship to the ionic radii of the substitutional transition metals Fe 3+, Cr 3+ and Ni 2+ for Ti 4+ in octahedral site. It was found that solubility limits of 3d elements in lithium titanium oxide with ramsdellite structure were investigated in a shorter time by combinatorial method.

Analysis of single crystals based on strontium–lithium–titanium oxides by inductively coupled plasma atomic emission spectrometry

The content of the major components Sr, Li, Ti, Fe and Nb in single crystals, based on strontium–lithium–titanium oxides has been determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The single crystals have been grown from high temperature solutions of the oxide systems SrO–TiO 2–LiBO 2 or SrO–TiO 2–Fe 2O 3–Nb 2O 5–LiBO 2. Hydrofluoric and boric acids have been used for sample decomposition. Both the inter-element spectral interferences and multiplicative interferences were studied. The adverse effects of spectral interferences on analytical results were removed by the selection of analysis lines free of line and wing background interferences. Addition of boric acid (0.04–0.08%) did not change appreciably the slope of the calibration graphs for Li, Sr, Ti, Fe and Nb. No significant statistical differences were found between the results obtained by both ICP-AES and electron-probe microanalysis for the above-mentioned single crystals. On the basis of the analytical information the composition of the crystallized phase SrLi 2Ti 5.16Nb 0.58Fe 0.26O 14.16 was established.

New oxide materials based on strontium lithium titanium oxide phase SrLi2Ti6O14

New oxide materials based on strontium lithium titanium oxide phase SrLi₂Ti₆O₁₄