Rounded edge graphite

The graphite materials used in this study include SL-20 which is round edge natural graphite, and SLC-1015 which is the surface coated natural graphite from the type of untreated precursor SL-20, and both samples were obtained from Superior Graphite Co. 

SEM representative images of the surface treated natural graphite SLC-1015 and its untreated precursor SL-20 are shown by Figure 1. The graphite particles with the rounded edges having less active sites tend to limit the reaction on its surfaces and thus improve its cycling performance and safety. 

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

Figure 11. Specific capacity versus cycle number plots of Superior Graphite Co. natural graphite (rounded edge type), uncoated (pristine) MAG-10 graphite, and carbon-coated MAG-10 graphite in respective Li cells cycled at room temperature in 30% PC blended electrolyte.

The electric furnaces, in which this reaction is carried out, are ca. 15 3 3 m- in size and are lined with refractory material. Electrodes at opposite ends are connected to a graphite core. The furnace is filled round this core with the reaction mixture and electrically heated to 2200 to 2400°C. The heating up time is ca. 18 h and the reaction time a further ca. 18 h. After cooling, the sides of the furnaces are removed and the unreacted material on the edges removed. The silicon carbide, which has formed round the graphite core, is broken up and separated into different qualities. 

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