Li+ doping

Kido et al. reported using a Li-doped Alq3 layer as a CIM, which generates the radical anions of Alq3 that, in turn, serve as intrinsic electron carriers and lead to improved device performance [57], Lithium salts such as acetate or benzoate can also enhance the electron injection by a similar mechanism [58],... 

Driscoll et al. (259,266) concluded that the catalytically active species for OCM are Li -0 centers, which are equilibrated with surface 0 centers via hole transport, because vacant hole sites are formed by Li doping in the surface and bulk. However, direct observation of the Li -0 pairs is difficult, because they are present at high temperatures and are formed only in an O2 atmosphere (267). It has been reported that 0 species in other alkali-doped MgO catalysts are also active for OCM (265,268). 

Finally, we remark that precisely because of its strong basicity, low coordination oxygen atoms O " are very reactive and may reconvert to surface OH" in the presence of water formed during the pseudoionone synthesis (see reachon scheme 1). Recent reports confirm that the surface of metal oxides with basic character are often restructuring during the reaction (15). Thus, the formation of pseudoionones on Li-doped MgO may be accompanied by the gradual modification of the catalyst surface, by reconverting... 

A few systems obtained by the ECD method comprise polyacetylene tetra-chloroferrate [87] [CH(FeCl4)y]x and tetrachloroaluminate [CH(A1C14)X], Li+ doping (LiC104 in propylene carbonate) [86] or [(CH)x(SbF6)y] (anodic oxidation in a solution of [CH3(CH2)3]4 N+ SbFg in dry CH2C12) [92]. 

The theoretical works shown above on the electronic structures of Li-doped nanographene sheets give an important clue to explain the electronic features of Li ion batteries. 

Yata, S., Y. Hato, H. Kinoshita, N. Ando, A. Anekawa, T. Hashimoto, M. Yamaguchi, K. Tanaka, and T. Yamabe. 1995. Characteristics of deeply Li-doped polyacenic semiconductor material and fabrication of a Li secondary battery. Synth. Metals 73 273-277. 

Yagi, M., R. Saito, T. Kimura, G. Dresselhaus, and M. S. Dresselhaus. 1999. Electronic states in heavily Li-doped graphite nanoclusters. J. Mater. Res. 14 3799-3804. 

Zhou GW, Li H, Sun HP, Yu DP, Wang YQ, Huang XJ, Chen LQ, Zhang Z. Controlled Li doping of Si nanowires by electrochemical insertion method. Appl Phys Lett 1999 75 2447-2449. 

High cycling efficiency is also obtained in LiAsF6-2Me-THF solutions containing 2-methyl furan [262], We attribute it mostly to the effect of Li doping by arsenic compounds, which in this case is not interfered with by pronounced solvent reactions [50], since 2Me-THF is one of the least reactive toward Li of all the commonly used solvents. 

Figure 28 Typical chronopotentiometric profile of a disordered carbon charged-discharged in Li salt-alkyl carbonate solution. The carbon was a Li doped polyacenic semiconductor (PAS) obtained by heat treatment of phenolformaldehyde resin [348]. Note the high capacity, the sloping potential profile and the hysteresis between the charge and discharge routes. (With copyrights from Elsevier Science Ltd., 1998.)...

In a detailed academic study, the application potential of Li-doped MgO, prepared via different synthetic routes and with different loadings of Li, was investigated [11], Catalysts were prepared via decomposition of single source precursors, wet impregnation, precipitation, and mixed milling. The materials were sieved to a particle size < 200 pm to avoid mass transfer limitations. Certain preparations (e.g. precipitation) result in very fluffy materials in such cases, the catalysts were pressed in advance of sieving. 

In Equation (35), an estimation of the mass transfer with the Weisz-Prater criterion is given. By taking always reasonable estimations or overestimated values, one obtains a good conclusion if mass transfer is present or not. For the characteristic length, 200 pm as particle diameter is used. The reaction order usually has the value of 1 to 4 a value of 4 would therefore be a worst case scenario. The catalyst density can be measured, or the common estimation of 1.3 kg/m3 can be used, which should not be too erroneous for Li-doped MgO. The observed reaction rate re is calculated from the concentration of CH4 at the inlet of the reaction cch4 0 multiplied with the highest observed conversion of 25% (the highest initial value for all tested catalysts), divided by the inverse flow rate, corrected by the reactor temperature. The calculation of re is shown in Equation (33) ... 

Once this was done, the stability of the catalysts was determined by time on stream experiments, as shown in Figure 4.1.6 for Li/MgO samples prepared via wet impregnation. The time on stream experiments revealed that the Li-doped MgO catalyst is instable, irrespective of the preparation procedure or the Li-loading. After 40 h time... 

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