Preparation Of Li1 Research Articles

A cost-effective, ionically conductive and compressible oxychloride solid-state electrolyte for stable all-solid-state lithium-based batteries

To enable the development of all-solid-state batteries, an inorganic solid-state electrolyte should demonstrate high ionic conductivity (i.e., > 1 mS cm−1 at 25 °C), compressibility (e.g., > 90% density under 250−350 MPa), and cost-effectiveness (e.g., < $50/kg). Here we report the development and preparation of Li1.75ZrCl4.75O0.5 oxychloride solid-state electrolyte that demonstrates an ionic conductivity of 2.42 mS cm−1 at 25 °C, a compressibility enabling 94.2% density under 300 MPa and an estimated raw materials cost of $11.60/kg. As proof of concept, the Li1.75ZrCl4.75O0.5 is tested in combination with a LiNi0.8Mn0.1Co0.1O2-based positive electrode and a Li6PS5Cl-coated Li-In negative electrode in lab-scale cell configuration. This all-solid-state cell delivers a discharge capacity retention of 70.34% (final discharge capacity of 70.2 mAh g−1) after 2082 cycles at 1 A g−1, 25 °C and 1.5 tons of stacking pressure.

Preparation of Li1.2Ni0.2Mn0.6O2 hollow stratified sphere by self-template method and surface vulcanization

As promising cathode materials in Li-ion batteries, Li-rich layered oxides still suffer from unsatisfactory first Coulomb efficiency and cyclic stability. Herein, the hollow structure of Li1.2Mn0.6Ni0.2O2 was purposefully designed by a self-template method with MnO2 as the precursor. Then, the Ni-Mn sulfides coated layers was formed on the surface of the material by avulcanization with thioacetamide. It is proved that the Ni-Mn sulfides are evenly distributed on the surface, and the vulcanization process enlarges the internal hollow volume, which greatly improved the electrochemical performance of cathode materials. The optimal sample was delivered an initial discharge specific capacities of 270.2 mA h g−1 with highest coulomb efficiency (79.3 %) and remarkable cycling stability of 95.6% capacity retention after 100 cycles at 0.1C.

The Preparation of Li1.5Al0.5Ge1.5(PO4)3 Glass-Ceramics with Lithium-Ion Conductivity from an Oxalate Precursor

An Li1.5Al0.5Ge1.5(PO4)3 glass-ceramic solid electrolyte having a NASICON structure and possessing lithium-ion conductivity is prepared. The differential scanning calorimetry data show that the oxalate precursor significantly reduces the melting temperature of a raw material by 200–300°C to synthesize the Li1.5Al0.5Ge1.5(PO4)3 glass ceramics. The glass appears to be transparent and colorless after melting at 1150°C and subsequent cooling. The glass transition temperature is 512°C, whereas an intense exothermic crystallization peak of Li1.5Al0.5Ge1.5(PO4)3 is observed at 633°C. The monophase glass-ceramics, free of nonconductive impurities, is obtained via glass crystallization at 850–900°C. The ionic conductivity of the Li1.5Al0.5Ge1.5(PO4)3 glass-ceramics is 2 × 10–4 S/cm at room temperature.

Preparation of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte via a sol-gel method using various Ti sources

ABSTRACT In this study, LATP (Li1.3Al0.3Ti1.7(PO4)3) solid electrolyte is prepared by a sol-gel process using Ti(C2H5O)4, Ti(n-C3H7O)4 and Ti(n-C4H9O)4 as Ti sources to examine the influence of the Ti source on the electrochemical properties of produced LATP. LATP is successfully produced in all cases, however, AlPO4 impurity is formed in the Ti(n-C3H7O)4 and Ti(n-C4H9O)4 samples due to insufficient formation of Ti-O-Al network. In contrast, the AlPO4 formation is not observed in the Ti(C2H5O)4 sample. Also, the Ti(C2H5O)4 sample shows the highest sinterability and the largest grain size among the three samples. As a result, the Ti(C2H5O)4 sample shows the highest Li ion conductivity due to high grain boundary conductivity and less impurity phase. The selection of Ti source is a key to obtain high conductive LATP solid electrolyte.

Preparation of porous Li1.2Mn0.54Ni0.13Co0.13O2 micro-cubes for high-capacity lithium-ion batteries

Abstract We report on the preparation of Li1.2Mn0.54Ni0.13Co0.13O2 micro-cubes for the applications of high-capacity lithium-ion batteries. Metal oxalate precursors with a cubic morphology are firstly prepared via a coprecipitation method in the mixed solutions containing ethanol, methanol and water. After controlled calcination treatment, the metal oxalate precursors are transformed into Li-rich layered oxide micro-cubes which possess a porous micro-nano structure consisting of interconnected nano-sized subunits. It is observed that a small amount of Li4Mn5O12 spinel is integrated with the layered phase in the micro-cubes. Compared with the micro-long-rod counterpart which is prepared under similar condition but only possess layered structure, the micro-cube cathode has excellent electrochemical properties that not only possess a high capacity of 278 mA h g−1 with an initial Coulombic efficiency of 88.3%, but also outstanding capacity retentions of 99.3% after 100 cycles and 89.7% after 200 cycles at 1 C. The excellent electrochemical properties of Li1.2Mn0.54Ni0.13Co0.13O2 micro-cube cathode may arise from the contributions from both the porous micro-nano structure and Li4Mn5O12 spinel phase, which can enhance the efficient contact of electrolyte and the transportation of Li+ as well as maintain the structure stability.

Preparation of Li1.5Al0.5Ge1.5(PO4)3 solid electrolytes via the co-precipitation method

ABSTRACTLi1.5Al0.5Ge1.5(PO4)3 (LAGP) is prepared through co-precipitation and sintered at various temperatures (650 ~ 900°C). Impurity formation is affected by the sintering temperature. Although impurity formation is observed in all the samples, it becomes more prominent at high sintering temperatures. The crystallinity of LAGP increased with the sintering temperature as evidenced by SEM observations, which show that the edges of the grains become sharper with increases in the sintering temperature. However, the formation of pores is also observed in the pellets sintered at 850°C and 900°C. As a result, the highest Li ion conductivity (7.8 × 10−5 S cm−1) is obtained when the sintering temperature is 800°C due to the high crystallinity of LAGP and absence of pore formation. This conductivity value is comparable to previously reported values and LAGP synthesis temperature is 400°C lower than required by the melt-quenching method. The co-precipitation method is a promising method for the preparation of LAGP solid electrolytes at low temperatures.

Preparation of Li1.5Al0.5Ti1.5(PO4)3 solid electrolyte via a co-precipitation method

The co-precipitation method can make the materials react uniformly at molecular level and has the advantages of lower polycrystalline synthesized temperature and shorter sintering time. Therefore, it is expected that the mass production of Li1.5Al0.5Ti1.5(PO4)3 (LATP) solid electrolyte would be possible by application of the co-precipitation method for LATP preparation. In this study, an application of the co-precipitation method for a preparation of LATP solid electrolyte is attempted. Crystallized LATP powder is obtained by heating precipitant containing Li, Al, Ti, and PO4 at 800 °C for 30 min. The LATP bulk sintered pellet is successfully prepared using the crystallized LATP powder by calcinating at 1,050 °C. The cross-sectional SEM images show that many crystal grains exist, and the grains are in good contact with each other, i.e., there is no void space. All diffraction peaks of the pellet are attributed to LATP in XRD pattern. The sintered pellet is obtained by calcinating at 1,050 °C, which is more than 150 °C lower than that of conventional method. The LATP solid electrolyte shows a good conductivity which is 1.4 × 10−3 S cm−1 for bulk and 1.5 × 10−4 S cm−1 for total conductivities, respectively.

An improved carbonate precipitation method for the preparation of Li1.2Ni0.12Co0.12Mn0.56O2 cathode material

The precursor of (Ni0.15Co0.15Mn0.7)CO3 has been synthesized by a carbonate precipitation method, which was used to prepare high-capacity cathode material Li1.2Ni0.12Co0.12Mn0.56O2 for lithium-ion batteries. Carbonate precipitation was conducted using NH4HCO3 solution as the precipitation reagent. Two different feeding ways were adopted during the precipitation process. The physical properties of the precursor and the resulting Li1.2Ni0.12Co0.12Mn0.56O2 were characterized in detail, and the electrochemical properties of the prepared Li1.2Ni0.12Co0.12Mn0.56O2 powers were evaluated. It was found that the structural and morphological properties of the precursor and the final material were effectively improved by the ordered addition method. Electrochemical studies confirmed that the Li1.2Ni0.12Co0.12Mn0.56O2 synthesized by ordered addition method exhibited a higher capacity of 287.3 mAh g−1, and the capacity retention after 30 cycles was 90.5 %.

Preparation of powders and films of the lithium ion conducting solid electrolyte Li1.3Al0.3Ti1.7(PO4)3

This paper describes a process for the preparation of powders and films of the lithium ion conducting solid electrolyte Li1.3Al0.3Ti1.7(PO4)3 from peroxide solutions. The use of peroxide solutions ensures the preparation of Li1.3Al0.3Ti1.7(PO4)3 with a room-temperature electrical conductivity of (4–5) × 10−4 S/cm by calcining a precursor at 800°C. The synthesized Li1.3Al0.3Ti1.7(PO4)3 powders were characterized by X-ray diffraction, thermal analysis (DTA/TG), and ionic and electronic conductivity measurements. The growth of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte films is described.

Preparation of Li1.5Al0.5Ti1.5(PO4)3 solid electrolyte via a sol–gel route using various Al sources

Li1.5Al0.5Ti1.5(PO4)3 (LATP) has received much attention as a solid electrolyte for lithium ion batteries due to its high Li ion conductivity. In this study, the LATP is prepared by a sol–gel process using water-soluble Al(NO3)3 and water-insoluble Al(C3H7O)3 as Al sources to examine the influence of the Al source on the properties of the produced LATP. The LATP is successfully produced in both cases; however, a small amount of AlPO4 impurity is formed in the Al(NO3)3 sample due to insufficient mixing of the water-insoluble Ti(C3H7O)4 with the water-soluble Al(NO3)3. In contrast, the AlPO4 formation is not observed in the Al(C3H7O)3 sample. The Li ion conductivity of the Al(C3H7O)3 sample is higher than that of the Al(NO3)3 sample, implying that the AlPO4 impurity acts as a resistance layer. The performance of LATP prepared by the sol–gel method is strongly affected by the Al sources, and the water-insoluble Al source is suitable for water-insoluble Ti(C3H7O)4, which has been the most widely used Ti source to date.

Synthesis and Tunable Luminescent Properties of Red PhosphorLi1−mAgmLa0.99−nYnPr0.01(MoO4)2with Blue Excitation for WhiteLEDs

Preparation ofLi1−mAgmLa0.99−nYnPr0.01(MoO4)2phosphors was done by a convenient method of solid‐state reaction technique in the air. The effects of synthesis temperature, substitution ofAg+,Y3+on theLiLa(MoO4)2crystal structure, and luminescence properties ofPr3+in the molybdate host are investigated systematically. The observed excitation and emission spectra indicate that the phosphor can be excited effectively by the blue light (440–500 nm) and exhibit a satisfactory red emission at 605 and 649 nm, respectively. The substitution of a littleAg+forLi+enhances thePr3+luminescence intensity drastically. The variability ofY3+andLa3+content changes the emission intensity ratio of the1D2 → 3H4and3P0 → 3F2transition, so that theCIEchromaticity coordinates of the as‐preparedLi1−mAgmLa0.99−nYnPr0.01(MoO4)2phosphors are tuned from (0.639, 0.351) to (0.653, 0.337).

Preparation of Li1.03Mn1.97O4 and Li1.06Mn1.94O4 by the Polymer Precursor Method and X-ray, Neutron Diffraction and Electrochemical Studies

The compounds, Li1.03Mn1.97O4 and Li1.06Mn1.94O4 were prepared by the polymer precursor method followed by heat treatment at 650°C for 6 hours in air. X-ray and neutron diffraction, scanning electron microscopy, and the Brunauer-Emmett-Teller surface area and density determination techniques were used to characterise the compounds. The lattice parameters obtained using neutron diffraction data of Li1.03Mn1.97O4 and Li1.06Mn1.94O4 are smaller than the parent LiMn2O4 at a = 8.20717(17) and 8.22899(13) Å, respectively. Cyclic voltammetry studies were carried out in the potential range of 3.5-4.4V at scan rate of 0.058 mV/sec. Li-doped LiMn2O4 showed the main cathodic and anodic redox peaks at ∼3.9/4.0 and ∼4.1/4.15V, respectively. The reversible charge capacities of Li1.03Mn1.97O4 with an applied current rate of 360 mA g−1 at the end of 2nd and 230 th cycle are 88 and 83 (±3) mAh g−1, respectively. At a current rate of 600 mA g−1 these charge capacities are 67 and 61 (±3) mAh g−1, respectively. Li1.06Mn1.94O4 shows a capacity of 64 and 62 (±3) mAh g−1 at the end of 2nd and 100th cycles, respectively, at a current rate of 360 mA g−1.

Preparation of Li1+y−xZnxMn2−yO4 Spinel as a Cathode Material for Li+-batteries

Abstract Li1+y−xZnxMn2−yO4 spinel has been synthesized using LiOH, Zn(NO3)2, and MnO2. The substitution of Zn2+ for Li+ in the tetrahedral 8a site of spinel was successfully achieved by adjustment of the synthetic conditions, such as atmosphere and cooling rate. The performance of 8a site Zn-doped spinel was investigated in the terms of initial capacity and polarization.