Lithium Zinc Titanate Research Articles

Characterization of lithium zinc titanate doped with metal ions as anode materials for lithium ion batteries.

With the aim of improving the ionic and electronic conductivities of Li2ZnTi3O8 for high performance lithium ion battery applications, Li2Zn0.9M0.1Ti3O8 (M = Li+, Cu2+, Al3+, Ti4+, Nb5+, Mo6+) compounds are successfully fabricated using facile high temperature calcination at 800 °C. Physical characterization and lithium ion reversible storage demonstrate that Zn-site substitution by multivalent metal ions is beneficial for improving the migration rate of ions and electrons of Li2ZnTi3O8. X-ray diffraction analysis and scanning electron microscopy reveal that the crystal structure and microscopic morphology of bare Li2ZnTi3O8 do not change by introducing a small amount of foreign metal ions. As a result, Li2Zn0.9Nb0.1Ti3O8 retains a reversible capacity as high as 198 mA h g-1 at the end of the 500th cycle among all samples. Even when cycled at high temperatures, Li2Zn0.9Nb0.1Ti3O8 still maintains excellent reversible discharge capacities of 210 mA h g-1 and 196 mA h g-1 at 1000 mA g-1 for the 100th cycle at 50 °C and 60 °C, respectively. All the conclusions indicate that Li2Zn0.9Nb0.1Ti3O8 is a high-performance anode material for large-scale energy storage devices.

Reversible Movement of Zn2+ Ions with Zero-Strain Characteristic: Clarifying the Reaction Mechanism of Li2ZnTi3O8

Lithium zinc titanate spinel, Li2ZnTi3O8, has received significant attention as a negative electrode material for lithium-ion batteries (LIBs). However, its reaction mechanism has not been fully clarified yet, particularly for the large voltage hysteresis between discharge and charge curves. We hence closely examined (Li1-xZnx)[Li1/3+x/3Ti5/3-x/3]O4 (LZTO) with 0 < x ≤ 0.5 by measuring its open-circuit voltage (OCV) and recording synchrotron radiation X-ray diffraction (XRD) patterns. Here, LZTO is a solid solution of Li[Li1/3Ti5/3]O4 (x = 0) and Li2ZnTi3O8 (x = 0.5), both of which have a spinel-framework structure. For the x = 0.5 sample, the OCV of the discharge reaction differed from that of the charge reaction, particularly at a capacity above 50 mAh·g-1. This difference was due to the migration of Zn2+ ions from tetrahedral sites to octahedral sites, and the Zn2+ ions moved back to tetrahedral sites during the charge reaction. Despite these drastic movements of Zn2+ ions, the cubic lattice parameter of the spinel was maintained during the whole reaction, i.e., zero strain. Perfect zero strain, which has never been reported for any LIB materials, was achieved with the x = 0.25 sample. The reaction mechanism with x = 0.5 and the contributions of the amount of Zn ions are discussed in detail.

Review and prospect of Li2ZnTi3O8-based anode materials for Li-ion battery

Rechargeable lithium-ion batteries (LIBs) are considered as one of the most promising power sources for energy storage system for a wide variety of applications such as personal electronic devices and large-format storage devices. The anode material usually plays a key role in the determination of the safety and cycling stability of LIBs. Among all anode materials, lithium zinc titanate (Li2ZnTi3O8) has been considered as one the most promising anode candidates because it has high theoretical capacity (227 mAh g−1), low working plateau, and excellent thermal and structure stability. However, Li2ZnTi3O8-based batteries always suffer from severe capacity deterioration due to the poor conductivity. Hence, it is necessary to systematically and comprehensively summarize the progress in understanding and modifying Li2ZnTi3O8 anode from various aspects. In this review, we present a general overview of the structural features and the electrochemical behavior of Li2ZnTi3O8. We then offer a comprehensive review of the recent advancements of the breakthroughs in the past decade in the synthesis, doping, and surface coating of Li2ZnTi3O8. At last, we highlight the critical challenges facing us today and future perspectives for further development of Li2ZnTi3O8-based anodes.

Electrochemical Properties of Li2ZnTi3O8/C Nanomaterials

Li2ZnTi3O8/C nanomaterials are synthesized using the sol-gel method; polyvinylidene fluoride (PVDF) and sucrose are used as carbon sources. The materials are characterized using XRD, TEM, TGA, and Raman spectroscopy. The influence of the carbon precursor and the annealing temperature on the electrochemical properties of the materials is investigated. It has been shown that the addition of both polyvinylidene fluoride and sucrose leads to the formation of nanosized lithium zinc titanate and high conductive carbon. This modification leads to the enhancement of electrochemical properties of the materials; namely, the discharge capacity of Li2ZnTi3O8 and Li2ZnTi3O8/C-5F annealed at 800°C under a current of 20 mA/g are 180 and 227 mA h/g, respectively.

Synthesis of high rate capability N-doped carbon coated on lithium zinc titanate via a surfactant-assisted solid-state route

Ammonium oxalate as a pore-foaming agent enhances total pore volumes and Tween 80 as a surfactant helps to uniformly disperse raw materials.

High rate performance Fe doped lithium zinc titanate anode material synthesized by one-pot co-precipitation for lithium ion battery

Fe doped lithium zinc titanate anode material has been synthesized via one-pot co-precipitation method for the first time. It is found that Fe element can enhance the electrochemical property of lithium zinc titanate obviously. Li2ZnFe0.05Ti2.95O8 particle shows largest specific capacity and best cyclic performance at high current densities among other particles. The introduction of Fe element improved electrochemical performance of the Li2ZnTi3O8 should be owing to the enhancement of the electric conductivity and lithium ion diffusivity of Li2ZnTi3O8.

Investigation of N-doped carbon-coated lithium zinc titanate using chitin as a carbon source for lithium-ion batteries

Nitrogen-doped carbon-coated Li2ZnTi3O8 (NC-LZTO) anode material was fabricated with chitin as a carbon source by precoating process via a facile solid-state reaction method. The effects of nitrogen-doped carbon layer on the crystal structure, surface morphology, and electrochemical performances were studied. The NC-LZTO samples show the significant improvement in rate capability compared with carbon-coated Li2ZnTi3O8 (C-LZTO) sample derived from glucose and naked Li2ZnTi3O8 (LZTO) sample. At the current rates of 0.5, 1, 2, 5, and 10 C, the discharge-specific capacities of the NC-LZTO sample are 275.6, 262.8, 244.8, 217, and 190.6 mAh g−1, respectively. After 200 cycles at 2 C, its capacity retention is 98.7%. The increased electrochemical performance of NC-LZTO can be ascribed to the larger specific surface, smaller particle size, and better electronic conductivity.

Synthesis of high performance carbon-coated lithium zinc titanate via an EDTA-assisted route

Carbon-coated Li2ZnTi3O8 (Li2ZnTi3O8@C) anode materials have been firstly synthesized via an EDTA-assisted solid-state route using EDTA as the carbon source and chelating agent. The effects of sintering time on the structures and physicochemical properties of the Li2ZnTi3O8@C anodes are also systematically studied. The results show that the Li2ZnTi3O8 particles are nano-sized and coated with carbon layer. The conductive carbon greatly improves the electrochemical performance of Li2ZnTi3O8@C. Li2ZnTi3O8@C-700-3 with the sintering time of 3 h delivers large specific capacities and presents good cyclic performance at high current densities. The largest capacities of 171.1 and 154.1 mAh g−1 are obtained at 4 and 5 A g−1, respectively. At the 100th cycle, 143.3 and 133.2 mAh g−1 are still kept for the sample at 4 and 5 A g−1, respectively. The good electrochemical performance of Li2ZnTi3O8@C-700-3 originates from the large pore size, proper specific surface area and particle size, and low charge-transfer resistance.

Effect of particle size on the conductive and electrochemical properties of Li2ZnTi3O8

We have studied the effect of final annealing temperature on the formation of lithium zinc titanate, its electrical conductivity, and its electrochemical performance. Li2ZnTi3O8 has been shown to form in a wide range of annealing temperatures, from 673 to 1073 K. Its particle size increases systematically with increasing annealing temperature, whereas its conductivity decreases. The highest electrochemical capacity at low currents is offered by the materials annealed at 773 and 873 K, and the highest cycling stability is offered by the material prepared at 873 K.

Effects of TiO2 starting materials on the synthesis of Li2ZnTi3O8 for lithium ion battery anode

Lithium zinc titanate (Li2ZnTi3O8) anode materials have been successfully synthesized using rutile-TiO2 with different particle sizes as titanium sources via a molten-salt method. Various physical and electrochemical methods are applied to characterize the effects of TiO2 particle sizes on the structures and physicochemical properties of the Li2ZnTi3O8 materials. When the particle size of TiO2 is too small (10nm), it is difficult to homogeneously mix TiO2 with the other raw materials. Thus, the final product Li2ZnTi3O8 has poor crystallinity, large particle size, small specific surface area, pore volume and average pore diameter, which are disadvantageous to its electrochemical performance. Using TiO2 with the proper particle size of 100nm as the titanium source, the Li2ZnTi3O8 (R-100-LZTO) with excellent electrochemical performance can be obtained. At 1Ag−1, 175.8 and 163.6mAhg−1 are delivered at the 1st and the 200th cycles, respectively. The largest capacities of 163, 133.3 and 122.5mAhg−1 are delivered at 2.5, 5 and 6Ag−1, respectively. The good high-rate performance of the R-100-LZTO originates from the good crystallinity, small particle size, large specific surface area and average pore diameter, low charge-transfer resistance and high Li+ diffusion coefficient.

MOFs as reactant: In situ synthesis of Li2ZnTi3O8@C–N nanocomposites as high performance anodes for lithium-ion batteries

Lithium zinc titanate (Li2ZnTi3O8) is a desirable anode material for lithium-ion batteries (LIBs) due to its low cost, non-toxicity and high safety. However, the low electronic conductivity and inferior rate capability hinder the commercial application of Li2ZnTi3O8. Carbon coating can not only effectively enhance the electronic conductivity of Li2ZnTi3O8 but also suppress the growth of particle size in the sintering process. In addition, carbon can provide extra capacity when using Li2ZnTi3O8/C as an anode. Here, a simple yet powerful strategy is introduced to in situ prepare nitrogen-doped carbon coating on Li2ZnTi3O8 nanoparticles using ZIF-8 as carbon, nitrogen and zinc sources. After sintering at 700°C the obtained nanocomposite shows large discharge specific capacity of 287.3mAhg−1 at 0.5Ag−1, excellent cycling stability (>90% capacity retention after 200cycles corresponding to the largest value at 2Ag−1) and outstanding rate capability at 4 and 5Ag−1. These properties, combined with its high safety and ease of fabrication, make such Li2ZnTi3O8@C–N nanocomposite an ideal anode candidate for LIBs.

Rational design of high-rate lithium zinc titanate anode electrode by modifying Cu current collector with graphene and Au nanoparticles

Lithium zinc titanate (Li2ZnTi3O8) is a desirable anode material for lithium ion batteries (LIBs) due to its low cost, non-toxicity and high safety. However, the low electronic conductivity and not perfect rate capability hinder the commercial application of Li2ZnTi3O8. Here, a facile and effective strategy is developed to fabricate the Li2ZnTi3O8 electrode using the Cu foil with grown graphene and deposited Au nanoparticles as the current collector. The graphene and Au nanoparticles greatly enhance the electrical conductivity of the current collector. The structured Cu current collector has rough interface which can strengthen the adhesion between the Li2ZnTi3O8 active material layer and the current collector, providing an excellent electron transport network and reducing the internal resistance of LIBs. The Li2ZnTi3O8 material supported on the unique structured Cu current collector demonstrates outstanding Li+ storage properties with the reversible capacity of 172.2 mAh g−1 after 100 cycles at high current density of 4 A g−1. Even at 6 A g−1, 148.4 mAh g−1 can be delivered. The improved rate capability of the structured Li2ZnTi3O8 electrode makes it a promising anode candidate for high performance LIBs.

High rate capacity nanocomposite lanthanum oxide coated lithium zinc titanate anode for rechargeable lithium-ion battery

Lithium zinc titanate (Li2ZnTi3O8) is an important titanium material of promising candidates for anode materials with superior electrochemical performance and thus has attracted extensive attention. Herein, high capacity, stable Li2ZnTi3O8/La2O3 nanocomposite for lithium-ion battery anode is prepared by a facile strategy. Compared to unmodified Li2ZnTi3O8, the Li2ZnTi3O8/La2O3 electrode display a high specific capacity of 188.6 mAh g−1 and remain as high as 147.7 mAh g−1 after 100 cycles at 2.0 A g−1. Moreover, a reversible capacity of 76.3 mAh g−1 can be obtained after 1000 cycles at 2.0 A g−1 and the retention is 42.7% for Li2ZnTi3O8/La2O3, which is much higher than un-coated Li2ZnTi3O8. The superior lithium storage performances of the Li2ZnTi3O8/La2O3 can be ascribed to the stable layer of protection, small particle size and large surface area. Cyclic voltammograms result reveals that the La2O3 coating layer reduces the polarization and improves the electrochemical activity of anode.

Long cycle life of carbon coated lithium zinc titanate using copper as conductive additive for lithium ion batteries

High conductivity pristine copper particles and carbon coated Li2ZnTi3O8 composite (Li2ZnTi3O8/C@Cu) is prepared by one-step sol-gel method followed by high temperature pyrolysis. Amorphous carbon coating layer reveals a thickness of 2.0-8.0nm on the outer surface of Li2ZnTi3O8 active grains, which improves the electronic conductivity and charge transfer rate of primary and secondary particles. Moreover, copper particles between particles could enhance the electronic transmission at large current densities and decrease diffusion resistance. As a result, Li2ZnTi3O8/C@Cu composite shows lower electrochemical polarization and quicker kinetic behavior compared to Li2ZnTi3O8/C. Cycled at 1000mAg−1, 2000mAg−1, and 3000mAg−1, Li2ZnTi3O8/C@Cu can deliver a reversible capacity of 124.4mAhg−1, 90.8mAhg−1, and 79.1mAhg−1 after 1000 cycles, which is much higher than the values of 70.7mAhg−1, 75.5mAhg−1, and 52.1mAhg−1 obtained by Li2ZnTi3O8/C. In addition to higher specific capacity, electrode polarization and cycle stability have been improved after adding copper particles. The improved electrochemical properties of Li2ZnTi3O8/C@Cu composite are attributed to the combination of copper additive and carbon layer.

Synthesis and electrochemical properties of lithium zinc titanate as an anode material for lithium ion batteries via microwave method

Lithium zinc titanate (Li2ZnTi3O8) anode material has been synthesized via a microwave method for the first time.

High performance carbon-coated lithium zinc titanate as an anode material for lithium-ion batteries

Carbon-coated Li2ZnTi3O8 (Li2ZnTi3O8/C) anodes have been successfully synthesized using β-cyclodextrin (β-CD) as the carbon source. The effects of carbon content on the structures and physicochemical properties of the Li2ZnTi3O8/C materials are also studied in detail. It is found that the Li2ZnTi3O8 particles are nano-sized and well disperse into the carbon networks. The carbon coating greatly enhances the electrochemical performance of Li2ZnTi3O8. Li2ZnTi3O8/C-2 with the carbon content of 6.85% shows large specific capacities and good cyclic performance at high current densities. The largest capacities of 169.1, 162.4 and 150.3mAhg−1 are delivered at 3, 4 and 5Ag−1, respectively. Cycling for 100 cycles, 160.5, 139.7 and 129.1mAhg−1 are kept for the sample at the three current densities mentioned above, respectively. The good electrochemical performance of the Li2ZnTi3O8/C-2 can be attributed to the good crystallinity, proper carbon content, large pore size, small particle size and low charge-transfer resistance.

ChemInform Abstract: High Performance Na‐Doped Lithium Zinc Titanate as Anode Material for Li‐Ion Batteries.

AbstractLi2‐xNaxZnTi3O8 (x = 0—0.20) are prepared by calcination of stoichiometric amounts of ball milled (12 h) nano‐TiO2, Li2CO3, Na2CO3, and Zn(OAc)2 (750 °C, 5 h).

Improved rate performance of amorphous carbon coated lithium zinc titanate anode material with alginic acid as carbon precursor and particle size controller

Carbon-coated Li2ZnTi3O8 composites with nano particle size and excellent rate performance are synthesized via a facile solid-state reaction route using alginic acid as carbon precursor. The results of characterization indicate that amorphous carbon layer is homogeneously coated on the surface of Li2ZnTi3O8 particles without any crystal structure change. The carbon-coated Li2ZnTi3O8 composite with 10wt.% alginic acid (Li2ZnTi3O8/C-10) shows the largest initial discharge specific capacity of 242.5, 190.0, 165.2 and 91.2mAhg−1 can be obtained after 100 cycles at 0.1, 0.5, 1.0 and 2.0Ag−1, respectively. EIS reveals that Li2ZnTi3O8/C-10 exhibits higher electronic conductivity and faster lithium ion diffusivity. The significant improvements of electrochemical performance are attributed to the carbon layer on the outer surface of Li2ZnTi3O8 active particles, which can restrain the growth of particles, enhance electronic conductivity and suppress electrolyte decomposition.

A new strategy for synthesis of lithium zinc titanate as an anode material for lithium ion batteries

Lithium zinc titanate (Li2ZnTi3O8) anode materials have been firstly synthesized via a molten-salt method using 0.38LiOH·H2O–0.62LiNO3 as eutectic molten salts. The effects of sintering temperature and sintering time on the structures and physicochemical properties of the Li2ZnTi3O8 materials are also studied in detail. It is found that Li2ZnTi3O8 obtained by sintering at 700°C for 3h exhibits a typical cubic spinel structure with P4332 space group. Nano-sized particles are presented and the particles are homogeneous for the Li2ZnTi3O8 prepared by sintering at 700°C for 3h. Electrochemical tests demonstrate that the sample possesses large capacities. The largest capacities of 167.8 and 142.4 mAh g−1 are delivered at 2 and 3Ag−1, respectively. 137.8 and 113.3mAhg−1 are kept for the sample at the 100th cycle at the two current densities, respectively. The large discharge specific capacities may be attributed to the good crystallinity, small particle size and low charge-transfer resistance of Li2ZnTi3O8.

High performance Na-doped lithium zinc titanate as anode material for Li-ion batteries

This finding can provide an experimental support to synthesize high performance Ti-based materials by Na doping.