Graphite, intercalation compounds oxide

If GO is used as a host lattice for Li+ in aprotic electrolytes, reversibility is improved [577]. The potential level is distinctly more positive than with donor GIC, at about —1 V vs. SHE. An all-solid-state Li/GO battery with PE0/LiC104 as solid electrolyte was reported by Mermoux and Touzain [578], but rechargeability is poor. Recently, the structure of graphite oxide was studied by its fluorination at 50-2()0 °C [579]. C-OH bonds were transformed into C-F bonds. The examples, in conjunction with Section 2, show that the formation or cleavage of covalent C-O (C-F) bonds makes the whole electrochemical process irreversible. Application was attempted in lithium primary batteries, which have a voltage of 2-2.5 V. Really reversible electrodes are only possible, however, with graphite intercalation compounds, which are characterized by weak polar bonds. 

Reaction of methyl or ethyl benzoate with the potassium-graphite intercalation compound CsK, in DME or THF under argon at 25 "C, followed by quenching with water and air oxidation, gives a 30% yield of phenanthraquinone (equation 3). The conversion of benzoin into phenanthraquinone by CkK at the layer edge of the intercalate, with loss of molecular hydrogen, had been described earlier. The overall process (equation 3) has been described by its discoverers as the hyperacyloin condensation. The conversion of methyl 4-alkylbenzoates into 3,6-dialkylphenanthraquinone has also been reported. ... 

Group 1. - 7Li NMR spectroscopy was used to characterise a lithium/ graphite intercalation compound with a formula close to LiC 1 In situ solid-state 7Li NMR data were reported for lithium inserted into disordered carbon. There was evidence for both Lis+ and metallic lithium species.2 7Li and 13C solid-state NMR spectra were used to characterise a mesoporous tantalum oxide lithium fulleride (Ceo) composite material.3... 

Cation- and anion-graphite intercalation compounds can be prepared by electrochemical reduction or oxidation of graphite in appropriate electrolytes. Such electrochemical solid-state reactions require mixed conductivity of the solid, i.e., existence of electronic and ionic conductivity. 

---