Effect of doping and crystallite size on the electrochemical performance of Li4Ti5O12

Karhunen, Tommi; Välikangas, Juho; Torvela, Tiina; Lähde, Anna; Lassi, Ulla; Jokiniemi, Jorma

doi:10.1016/j.jallcom.2015.10.125

Cited by 14 publications

(9 citation statements)

References 17 publications

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“…As the material is kept at the isothermal temperature (850 °C), the crystallite size is seen to increase, which suggests that an increase in reaction time results in an increase crystallite size and has been observed in lithium titanates before (Nugroho et al ., 2014). Cooling the undoped material shows little to no changes in crystallite size; however, the doped material shows a decrease, which can be due to the combined effect of rapid cooling of the material, sample shrinkage and the lattice constraints that is induced upon doping (Figure 17) (Hatfield et al, 1971; Karhunen et al, 2016). During the least-squares refinement process in Topas, the L-strain parameter was allowed to refine, which increased as the LTO formation progresses from 550 to 850 °C.…”

Section: Resultsmentioning

confidence: 99%

An investigation into the temperature phase transitions of synthesized lithium titanate materials doped with Al, Co, Ni and Mg byin situpowder X-ray diffraction

et al. 2020

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Li4Ti5O12 (LTO) and its doped analogues Li4Ti4.95M0.05O12 (M = Al3+, Co3+, Ni2+, and Mg2+) were synthesized and characterized using in situ PXRD to monitor the phase transitions during the sol–gel synthesis of the spinel material. These results are complimented by thermogravimetric analysis, which illustrates the decomposition of the materials synthesized, where the final LTO products are seen to form at approximately 550 °C. The material has an amorphous structure from room temperature, coupled with a crystalline phase which is speculated to be H2Ti2O5·H2O. This crystalline phase disappears at 250 °C, with the material still in the amorphous state. The crystalline LTO phase starts at approximately 550 °C, with anatase co-crystallizing with the spinel phase. Rutile appears at 600 °C and co-crystallizes with the final product at 850 °C, where anatase is no longer seen. The rutile impurity remains present after cooling the material to room temperature, and results indicate that prolonged heating at 850 °C is required to reduce the rutile content. Rietveld refinement of diffraction patterns show that the unit-cell parameter increases with increasing temperature, coupled with a decrease when cooling the sample. The crystallite sizes follow the same trend, with a significant increase above temperatures of 750 °C.

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Section: Resultsmentioning

confidence: 99%

An investigation into the temperature phase transitions of synthesized lithium titanate materials doped with Al, Co, Ni and Mg byin situpowder X-ray diffraction

et al. 2020

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“…Similarly, element doping modification can induce the reduction of Ti 4+ to more conductive Ti 3+ ions by substituting elements at positions in the LTO lattice, resulting in higher conductivity at the atomic level. [ 20,21 ] Although the doping method makes the LTO anode practical at a high rate, the introduction of heterogeneous ions is not conducive to maintaining the inherent cycling properties of the material. Another strategy for improving electrochemical performance is to ameliorate ion diffusion kinetics.…”

Section: Introductionmentioning

confidence: 99%

High‐Pressure Induction and Quantitative Regulation of Oxygen Vacancy Defects in Lithium Titanate

Qin

Liang

et al. 2023

Adv Funct Materials

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Inspired by the functional properties of ion defect induction and charge compensation in defect engineering, these methods are expected to be an effective strategy to solve the constraints of Li4Ti5O12 (LTO) inherent conductivity and diffusion dynamics, and further improve battery rate performance. The oxygen vacancy (OV) content in LTO can be controlled quantitatively by high‐pressure induction using the high‐pressure and high‐temperature (HPHT) method. In addition, the relationship between the electrochemical properties and OV is further explored. The theoretical calculations indicate that the OV defects cause the electrons to delocalize into the conduction band of the LTO, and thus fundamentally improve the intrinsic conductivity. In particular, the high‐pressure quenching strategy of HPHT causes LTO to instantly produce crack holes with massive crystalline layers, which can be regarded as storage for the electrolyte to facilitate ion diffusion. The fabricated LTO anodes containing OVs compensate for the limitation of the poor rate performance with a capacity of 176 mAh g−1 at 20 C. Pressure‐induced OV defects not only open up a new perspective in the field of lithium‐ion batteries (LIBs), but also provide a certain degree of freedom for the functional design characteristics of defect engineering.

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“…The coating of LTO with a conductive material improves electrical contact between particles but has no effect on lithium-ion diffusivity. On the other hand, both the lattice electronic conductivity and lithium-ion diffusivity can be strengthened by doping with metal ions (Cr 3+ , V 5+ , Ta 5+ , Co 3+ , Cu 2+ , Ga 3+ , Sc 3+ , Fe 3+ , Mg 2+ , Mn 4+ , and Nb 5+ ) in Li or Ti sites [17][18][19][20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Electrochemical Performance of Li4Ti5O12 by Niobium Doping for Pseudocapacitive Applications

Chandrasekhar

Dhananjaya

Hussain

et al. 2021

Micro

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Niobium-doped nanocrystalline Li4Ti5O12 (LTO) is synthesized by the solid-state reaction method, and the influence of dopant concentration (x = 2–10 mol%) on microstructural and electrochemical properties is studied. The X-ray diffraction and Raman patterns assessed the cubic spinel structure of Li4Ti5−xNbxO12 phase in all samples. Marginal changes in the lattice parameters, unit cell volume and dislocation density of LTO are observed with Nb substitution. The higher ionic radius of Nb induces a lattice expansion, which may be favorable for more ion intercalation/deintercalation. The SEM and TEM images display uniformly distributed nano-sized cubical particles. The represented (hkl) orientations of the SAED pattern and d-spacing (0.46 nm) between bright fringes confirm the well-crystallized LTO phase. The EDS and elemental mapping results demonstrate that Nb elements are uniformly doped in LTO with a proper stoichiometric ratio. The optimized 8%Nb-doped LTO electrode exhibits pseudocapacitive behavior and delivers a high specific capacitance of 497 F g−1 at a current density of 1 A g−1 with 92.3% of specific capacitance retention even after 5000 cycles.

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Effect of doping and crystallite size on the electrochemical performance of Li4Ti5O12

Cited by 14 publications

References 17 publications

An investigation into the temperature phase transitions of synthesized lithium titanate materials doped with Al, Co, Ni and Mg byin situpowder X-ray diffraction

An investigation into the temperature phase transitions of synthesized lithium titanate materials doped with Al, Co, Ni and Mg byin situpowder X-ray diffraction

High‐Pressure Induction and Quantitative Regulation of Oxygen Vacancy Defects in Lithium Titanate

Enhanced Electrochemical Performance of Li4Ti5O12 by Niobium Doping for Pseudocapacitive Applications

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