Rheological phase reaction

Figure 2. Plots of discharge capacity vs. the number of charge-discharge cycles for the cathodes LiMnjOiand LiMna.yCoooiYyOd (y=0.005,0.01,0.015) prepared by rheological phase reaction method. Voltage window is 3.6-4.3 V (vs. Li-metal). Tests were done at 0.2C rate for l-4th cycle, 0.5C rate for 5-14th cycle and finally at 1C rate for 15-60th cycle.

The rheological phase reaction method offers a new and simple way to prepare compounds and materials. The prepared compounds LiCo YyMn2.x.y04 show excellent capacity and cycleability. The cathode behavior of the LiMn204 can be greatly improved by simultaneous doping of cobalt and yttrium, and our results on LiCo, YyMn2.x-y04 show that the composition with x=0.02, y=0.015 exhibits the best high current rate (IC) capacity up to 60 cycles. The compound after optimization may find potential application in practical lithium-ion cells. 

The rheological phase reaction method is the process of preparing compounds or materials from a solid-liquid rheological mixture. That is, the solid reactants are fully mixed in a proper molar ratio, and made up by a proper amount of water or other solvents to a solid-liquid rheological body in which the solid particles and liquid substance are uniformly distributed, so that the product can be obtained under suitable experimental conditions. 

Many functional materials and compounds with new stmctures and properties, such as Sr[C6H4(C02)2] Tb a-Zn(0C6H4C02) Tb salicylate-doped zinc benzoate [Zn(Bzo)2 SalJ luminescent materials and non-crystalline tin-based composite oxide negative electrode materials, etc. have been obtained by means of the rheological phase reaction method [11-14]. 

It is of interest to note that great single crystal sample of Ni(Sal)2 4H20 [Sal = C5H4(0H)C02] has been obtained unexpectedly by rheological phase reaction method from Ni(OH)2 and salicylic acid. In addition, the single crystal of Cu(C6H5C02>3H has been prepared from CuO and benzoic acid. 

In the rheological phase system there are many advantages the surface area of solid particles can be efficiently utilized, the contact between solid particles and fluid is close and uniform, heat change is very efficient, local overheating can be avoided, and the reaction temperature can be easily controlled. In addition, many substances have greatly increased solubility and new reaction behavior in this state. 

Finally, the use of various synthetic routes, including the sol-gel process [122], rheological phase [123], predpitation/decomposition [124], hydrothermal [125] sonochemical [126] and combustion reactions [121], are all currently being widely investigated for the production of nanoionic materials for use in lithium ion batteries. 

In the industrial area, polyethylene is now being produced at entry pressures as high as A5, 000 to A7, 000 lb/in.2. One of the important consequences of the use of higher pressures and temperatures is to gain homogeneous (one phase) reaction conditions. In this way deleterious branching and poor rheological characteristics in fabricated products from polyethylenes may be avoided. In addition, improved film resin clarity may result. 

A porous spherical microstructure of Zr-doped Li4Ti50i2 can be prepared by a rheological phase in combination with a spray drying reaction. It has... 

Small temperature variations (+5°C) can change the phase structure of the paste dramatically, resulting in undesired rheological structures like gels. Good temperature control is therefore key in neutralization reactions. 

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