In Li-ion batteries

Simple 3d-metal oxides with Fe, Co, Ni, and Cu as metal have long been disregarded as possible reversible electrode materials for 

Various TMOs, such as cobalt, iron, and copper oxides with different M 0 ratios, were examined first and it was found that both the transition metal and lithium undergo a reversible redox reaction, while the oxygen atom is exchanged. In the case of cobalt oxide, the following reversible redox reaction is observed  

The size of the cobalt-containing particles is greatly reduced when the material is cycled. Starting from initial particle sizes in the 

The reversibility of such conversion systems was explained by an acido-basic concept which involves 0 anion transfer (Lux-Flood model) and is based ontheacidity or basicity of oxides (Smith scale). All oxides that react reversibly with Li are basic as is the Li20 itself.  

The concept can be generalized and applied to other systems which are based on nitrides, sulfides, and selenides. Thus, the general reaction can be written as follows, with M = metal and X = basic anion. 

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It is clear that there is enormous activity in the the search for better and cheaper anode materials for Li-ion batteries. In fact, it is not certain at this time whether carbon will remain the material of choice for this application. Nevertheless, large strides toward the optimization and understanding of carbons for Li-ion batteries have been made in the last 5 to 10 years. If continued progress is made, we can expect to see carbon materials in Li-ion batteries for a long timx to come. 

Chapter 11 reports the use of carbon materials in the fast growing consumer eleetronies applieation of lithium-ion batteries. The principles of operation of a lithium-ion battery and the mechanism of Li insertion are reviewed. The influence of the structure of carbon materials on anode performance is described. An extensive study of the behavior of various carbons as anodes in Li-ion batteries is reported. Carbons used in commereial Li-ion batteries are briefly reviewed. 

A great variety of polyolefin separator types are now used in Li ion batteries. They must be stable in the organic electrolytes. Typically they may not be properly wetted by the electrolytes of the optimized composition, e. g., mixtures with PC, PE, and others. Therefore some proprietary treatments are needed to provide hydrophilic behavior. Generally, a micro-porous nonwoven morphology with a large surface gives a good wettability. 

Composite electrodes made of two carbon components were evaluated experimentally as anodes for Li-ion batteries. The electrochemical activity of these electrodes in the reaction of reversible lithium intercalation ffom/to a solution of LiPF6 in ethyl carbonate and diethyl carbonate was studied. Compositions of the electrode material promising for the usage in Li-ion batteries were found. 

Therefore, there is a wide spectrum of carbon materials suitable for the usage in Li-ion batteries the choice of a specific one determined by many factors. According to Ref. 7, the percentage of various carbon materials used in commercial Li-ion batteries was as follows graphites - 43 %, hard carbons - 52 %, soft carbons - 5 %. 

Thus, the electrochemical properties of the individual carbon materials are not so high as to enable their commercial usage in Li-ion batteries. In order to improve the performance, we started making composite materials from two individual carbon ingredients. Figure 1 shows a typical result of electrochemical tests of an electrode made of a blend of graphite and soft carbon treated at 1100°C (Cl 100) in comparison with the discharge curves of the individual constituents. 

HTC materials have been used and structurally improved as electrodes in Li-ion batteries [30-32], Rechargeable lithium-ion batteries are the technical leading solution and essential to portable electronic devices. Owing to the rapid development of such equipment there is an increasing demand for lithium-ion batteries with higher energy density and a longer lifetime. 

The first application of HTC as an anode in Li-ion batteries was first reported by Huang et al. [30], After the hydrothermal carbonization of sugar, the resulting... 

Despite quite some progress reported in improving the performance and lifetime of anode materials, a great deal of research needs to be dedicated to the improvement of the cathode in Li-ion batteries. This task was addressed by hydrothermal carbon coating techniques. Thus, Olivine LiMP04 (Me = Mn, Fe, and Co) cathodes with a thin carbon coating have been prepared by a rapid, one-pot, microwave-assisted hy-... 

Layered solids such as graphite are interesting in separation and sorption applications and can be doped to give interesting materials properties as in Li ion batteries. Their intercalation behaviour is best described by the Daumas-Herold model. 

To get high-rate performance in Li-ion batteries, Moriguchi et al. [209] have studied the nanocomposite of Ti02 and CNTs. SWCNT-containing mesoporous Ti02 has shown better rate performance compared to that of the Ti02 without CNTs. 

Increased compatibility of these systems with composite electrodes, thus making them suitable for use in Li ion batteries... 

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