Lithiated manganese dioxides

The maximum Li uptake in SG-BR x(Li) = 0.85 is in good agreement with the concentration of Mn ions (the average valence of Mn ions is Zmh = 3.68), which are reduced to Mn during the intercalation reaction (discharge process) that occurs with a significant contraction 7.5 % of the host lattice. Pereira-Ramos et al. [39] reported that the faradaic yield recovered for SG-BRr is twofold greater than that of BR. Such a result can be understood in terms of faster Li -ion kinetics, 

6 Cathode Materials with Monoatomic Ions in a Three-Dimensional Framework 

The difficulties met with the LiMn204 spinel that are reported in the next section have also motivated the investigation of several non-spinel manganese oxides [16].LiMn02 is known to exist in several phases. Two of them are the high 

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Yoshio M, Nakamura H, Xia Y (1999) Lithiated manganese dioxide Lio.33Mn02 as a 3 V cathode for lithium batteries. Electrochim Acta 45 273-283... 

It should be noted, however, that the lack of electron density in the 7t-system may be bypassed by creating local (T-electron density by lithiation and reaction with suitable electrophiles. Quenching of lithiated alkoxy-l,2,3-triazines with aromatic aldehydes generates (a-hydroxybenzyl)-l,2,3-triazines, products of an electrophilic attack on carbon. Dehydrogenation of their alcohol function with manganese dioxide affords formal Friedel-Crafts acylation products <1998MI119>. Lithiation has been discussed from a theoretical point of view in Section 9.01.2.13, and practical implications are presented in Section 9.01.5.5. 

Figure 1.6 shows a typical lithium ion cell consisting of a negative electrode current collector of copper (Cu), lithiated porous carbon as a negative electrode (Li,C6), lithiated porous manganese dioxide (LiyMn204) as a positive electrode, a positive electrode current collector of aluminum (Al), and a separator. 

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