Precursors graphite

High aromatic PODA t5 es, such as poly(p-phenylene-l,3,4-oxadiazole), can be graphitized to yield a high quality graphite. The graphitization takes place at 2,800-3,000°C. From a heat-treated PODA film at 3000°C, an electrical conductivity of 1.4—1.8 10 Scm has been obtained. Graphite fibers with excellent mechanical properties have been obtained. 

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Figure 1. SEM images of (a) untreated natural graphite precursor SL-20 and (b) surface treated natural graphite with round edge shape (SLC-1015).

For illustrative purposes, the process of deposition of Si onto graphite is being used as an example. The 15 pm natural graphite precursors were introduced into the industrial size chemical vapor deposition reactor, where a thermal decomposition of silane (SiH4) into the silicon and hydrogen was taking place under inert gas in accordance with the equation (1) ... 

The comparative 2016 coin cell data of the uncoated vs. Si-coated spheroidized natural graphite precursor vs Li metal counter electrode (Figure 5) reveals a remarkable effect of metal addition onto the reversible capacity of anode. Thus, the starting material s reversible capacity increased from approximately 350 mAh/g to over 510 mAh/g (data taken at 0.8V vs Li/Li+), which is 1.37 times higher than the theoretical value of the reversible capacity for graphite. 

The pyrolysis of organic fibers used as graphite precursors is a multistage process. The three principal graphite precursors are PAN, pitch, and rayon, with PAN as the predominant product. 

A sufficiently high concentration of atomic hydrogen to etch graphite and suppress gaseous graphite precursors must be provided. 

As shown in Table 4.1, the graphite precursors can be divided into two major classes (a) aromatic hydrocarbons emd flj) polymers, each with different carbonization characteristics. 

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