Charge artificial graphite

The most important parameter of a lithium ion accumulator, its specific energy, of course depends on how much - reversibly dischargeable - hthium is stored in the carbon host lattice. The ideal maximum charge of the sum formula LiCe corresponds to the specific capacity of 372 mAh g. In practice natural graphite shows 330 to 350mAh g, artificial graphite a bit less. 

FIGURE 34.4 Representation of irreversible capacity asso-ciaed with the first charge/discharge process, (a) Coke, (b) Artificial graphite. 

Fig. 5 Charge-discharge profiles of graphitized mesophase pitch-based caibon fibers at 3000 °C and artificial graphite, a, c were obtained at the first eycle. b, d were obtained at the second cycle. Reproduced from Ref. [26]...

Initial charge and discharge curves of (a) artificial graphite KS-44 (Lonza) and (b) the artificial graphite coated with coke obtained by heat treatment at 1000°C, in a 1.0 M LiC104 electrolyte in EC/DEC (v/v 1 1). (Adapted from Yoon, S. et al., /. Power Sources 94 68-73,2001.)... 

The optical properties of individual multi-wall CNTs (MWCNTs) are defined by their dielectric function, which is anisotropic in nature and matches very closely with that of bulk graphite [23]. However, the highly dense periodic arrays of MWCNTs display an artificial dielectric function, with a lower effective plasma frequency in a few hundreds of terahertz. Pendry [24] demonstrated that the electromagnetic response of a metallic array composed of thin metallic wires, excited by an electric field parallel to the wires is similar to that of a low-density plasma of very heavy charged particles, with a plasma frequency ojp. 

In general, the artificial (and generally incorrect) assumption was made that Acj) = 0 for a solid ionic conductor in contact with a graphite or noble metal electrode in the absence of an externally applied potential. The temperature and dopant level dependence of the experimental capacitance was then compared with the factor (2K Qe%j /kT) or its equivalent. Other aspects of this work are discussed elsewhere (3,18). To the author s knowledge, the validity of Eq. 2 for a solid ionic conductor with a low enough bulk defect concentration to expect predominant diffuse space charge capacitance has not yet been shown. 

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