Prismatic surfaces

At the prismatic surfaces, the primary reduction reaction is the reduction of those solvent(s) co-intercalated inside graphite, whereas on the basal plane graphite sites, reduction reactions may proceed in an excess of... 

It should be noted here, that not only the (chemical and morphological) composition of the protective layers at the basal plane surfaces and prismatic surfaces is different, but that these layers also have completely different functions. At the prismatic surfaces, lithium ion transport into/ffom the graphite structure takes place by intercalation/de-intercalation. Here the formed protective layers of electrolyte decomposition products have to act as SEI, i.e., as transport medium for lithium cations. Those protective layers, which have been formed on/at the basal plane surfaces, where no lithium ion transport into/from the graphite structure takes place, have no SEI function. However, these non-SEI layers still protect these anode sites from further reduction reactions with the electrolyte. 

Figure 17. The basal plane and prismatic surfaces of graphite have different functions with respect to lithium intercalation and de-intercalation (= charge, discharge, self-discharge, etc.). As a consequence, only the electrolyte decomposition product layers at the prismatic surfaces have SEIfunction. Any processes related with electrolyte decomposition product layers at the basal plane surfaces (= non-SEI layers) therefore can not be directly related to electrochemical data such as charge, discharge, self-discharge, etc. The situation is even more complex as the SEI composition and morphology at the basal and prismatic surface...

The surface free energy of the prismatic edge surfaces Is much higher than the surface free energy of basal planes because their formation necessitates the breaking of covalent C-C bonds. Such a high surface free energy Is rapidly lowered by chemical and physical adsorption, and thus It Is difficult to obtain clean prismatic surface. 

Li C ), were obtained by chemical synthesis in the mid-1950s. [80, 81]. At ambient pressure, a maximum lithium content of one Li guest atom per six carbon host atoms can be reached for highly crystalline graphite (n>6 in LiC or a <1 in Li C ). The intercalation reaction proceeds via the prismatic surfaces (armchair and zig-zag faces). Through the basal plane... 

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