Influence of the emulsification conditions on the microstructures and electrochemical characteristics of spinel lithium manganese oxide powders

2003 ◽  
Vol 18 (3) ◽  
pp. 552-559 ◽  
Author(s):  
Chung-Hsin Lu ◽  
Yueh Lin
Keyword(s):  
Particle Size ◽  
Manganese Oxide ◽  
Aqueous Phase ◽  
Specific Capacity ◽  
Volume Ratio ◽  
Lithium Manganese Oxide ◽  
Electrochemical Characteristics ◽  
Oil Emulsion ◽  
Oxide Powders ◽  
Lithium Manganese

Lithium manganese oxide powders (LiMn2O4) with a spinel structure were synthesized via an optimized water-in-oil emulsion process. The influence of the emulsification conditions on the microstructures and physicochemical properties of LiMn2O4 powders was investigated. The phase purity of the synthesized powders significantly depends on the water-to-oil volume ratio in the emulsion. Increasing the water-to-oil ratio tends to decrease the stability of the emulsion that in turn leads to a segregation of water and oil phases. The unstable emulsion system results in the formation of an impure phase—Li2MnO3—that markedly decreases the charge and discharge capacities of the cathode materials. When water/oil volume ratio equals 1/5 or 1/10, monophasic spinel powders are formed at temperatures as low as 400 °C. In addition, decreasing the concentration of the aqueous phase substantially reduces the particle size of LiMn2O4 powders. Nanometered-LiMn2O4 powders with a particle size of 50 nm are obtained when the concentration of the aqueous phase is 1.0 M and the water-to-oil volume ratio is 1/5. Decreasing the particle size of LiMn2O4 powders was demonstrated to effectively increase the specific capacity and improve the cyclability of LiMn2O4 powders.

scholarly journals STUDY ON LITHIUM MANGANESE OXIDE SPINEL SYSTEM AS CATHODE MATERIALS FOR LITHIUM ION BATTERY: SYNTHESIS, MORPHOLOGICAL AND ELECTROCHEMICAL CHARACTERISTICS

2009 ◽  
Vol 12 (10) ◽  
pp. 64-71
Author(s):  
Binh Thi Xuan Lam ◽  
Phung My Loan Le ◽  
Thoa Thi Phuong Nguyen
Keyword(s):  
Manganese Oxide ◽  
Manganese Dioxide ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Lithium Manganese Oxide ◽  
Lithium Nitrate ◽  
Electrochemical Characteristics ◽  
Impregnation Method ◽  
Limn2o4 Spinel ◽  
Lithium Manganese

Lithium manganese oxide (LiMn2O4) spinel compounds were synthesized by melting impregnation method using manganese dioxide (MnO2) and lithium nitrate (LiNO3). Four sources of MnO2 raw materials were used: a commercial electrochemical manganese dioxide (EMD) supplied by Pin Con O factory; EMD thermal pretreated (EMDt); and MnO2 synthesized chemically (CMD) by oxidation of MnSO4 solution with K2S2O, and EMD synthesized in our laboratory. The effect of the MnO2 materials on the microstructure and electrochemical properties of LiMn2O4 is investigated by X-ray diffraction, scanning electron microscopy, and electrochemical measurements. The charge-discharge cycling behavior in Swagelok model of lithium-ion cells, using synthesized LiMn2O4 as cathode, lithium metal as anode and LiPF6 as electrolyte with Whatman glass separator, showed that the spinels from thermal treated EMDt and CMD gave higher (3100 mAh/g) and more stable values of specific capacity than the spinels from non-treated EMD.

Synthesis of Nanosized Lithium Manganate For Lithium-ion Secondary Batteries

2001 ◽  
Vol 703 ◽  
Author(s):  
Hsien-Cheng Wang ◽  
Yueh Lin ◽  
Ming-Chang Wen ◽  
Chung-Hsin Lu
Keyword(s):  
Particle Size ◽  
Aqueous Phase ◽  
Ultrafine Particles ◽  
Specific Capacity ◽  
Volume Ratio ◽  
Lithium Ion ◽  
Submicron Particles ◽  
Lithium Ions ◽  
Lithium Manganate ◽  
Precursor Powders

ABSTRACTNanosized lithium manganate powders are successfully synthesized via a newly developed reverse-microemulsion (RμE) process. Monophasic LiMn2O4 powders are obtained after calcining the precursor powders at 700°C. The particle size of the spinel compound significantly depends on the concentration of the aqueous phase. Increasing the water-to-oil volume ratio results in an increase in the particle size. While the aqueous phase is equal to 0.5 M, the size of the obtained LiMn2O4 powder is around 60-70 nm. It is found that the specific capacity of nanosized LiMn2O4 particles is greater than that of submicron particles. The large surface area of ultrafine particles is considered to facilitate the intercalation and deintercalation of lithium ions during the cycling test.

Electrochemical Characteristics of the Magnesium Titanium Composite Oxide-Coated Spinel-Type Lithium Manganese Oxide

2013 ◽  
Vol 591 ◽  
pp. 236-239
Author(s):  
Hai Quan Wang ◽  
Zhi Qiang Hu ◽  
Kun Yang ◽  
Yang Yu ◽  
Jing Xiao Liu ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Solid Phase ◽  
Electrochemical Analysis ◽  
Lithium Manganese Oxide ◽  
Electrochemical Characteristics ◽  
Spinel Type ◽  
Composite Oxide ◽  
X Ray ◽  
Lithium Manganese ◽  
Discharge Rates

In this experiment, the spinel-type lithium manganese oxide (LiMn2O4) prepared via solid-phase sintering method was coated with magnesium titanium composite oxide (MgTiOx) in the presence of polyvinyl pyrrolidone (PVP) under the ultrasonic wave. The crystal structures, surface morphologies and electrochemical properties of the sample prepared were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical analysis. The X-ray diffractions indicated that the LiMn2O4 coated with MgTiOx were similar to that of the pure LiMn2O4, and they both showed sharp and high peaks. The particles of the samples prepared with PVP did not aggregate obviously, and the samples were coated completely and homogeneously. At charge-discharge rates of 0.2C, the first discharge capacity can reach more than 120 mAh / g. Compared with pure LiMn2O4, the capacity attenuation of MgTiOx-coated LiMn2O4 reduced after fifty cycles, and showed good electrochemical performance.

Electrochemical characteristics of metal oxide-coated lithium manganese oxide (spinel type)

2004 ◽  
Vol 130 (1-2) ◽  
pp. 233-240 ◽  
Author(s):  
Seung-Won Lee ◽  
Kwang-Soo Kim ◽  
Ki-Lyoung Lee ◽  
Hee-Soo Moon ◽  
Hyun-Joong Kim ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Manganese Oxide ◽  
Lithium Manganese Oxide ◽  
Electrochemical Characteristics ◽  
Spinel Type ◽  
Lithium Manganese ◽  
Oxide Spinel ◽  
Lithium Manganese Oxide Spinel

The Influence of Particle Characteristic of Manganese Dioxide on Performance of Spinel Lithium Manganese Oxide

2016 ◽  
Vol 852 ◽  
pp. 816-821
Author(s):  
Wei Li ◽  
Wen Huai Tian ◽  
Lu Qi
Keyword(s):  
Manganese Oxide ◽  
Manganese Dioxide ◽  
Specific Capacity ◽  
Cycle Performance ◽  
Lithium Manganese Oxide ◽  
Spinel Lithium Manganese Oxide ◽  
Lithium Manganese ◽  
Liquid Impregnation ◽  
Particle Characteristic ◽  
Chemical Manganese Dioxide

Several kinds of chemical manganese dioxide with different particle characteristic were prepared by redox reaction in liquid phase. Then, spinel lithium manganese oxide was synthesized by liquid impregnation. The result implied that the influence of particle characteristic on test result is important. The spinel lithium manganese oxide prepared by spherical MnO2 has better cycle performance than the spinel lithium manganese oxide prepared by MnO2 with irregular shape .The spinel lithium manganese oxide with little particle size has high initial specific capacity. The spinel lithium manganese oxide prepared by MnO2 with anemone shape has high specific capacity and stable cycle performance.

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