Properties of synthetic graphite from boric acid-added pitch: performance as anode in lithium-ion batteries

Abstract

Synthetic graphite is produced by a heat treatment process using a carbon precursor (pitch, coke), but it is difficult to produce synthetic graphite of high quality due to the high-temperature process (minimum 3000 °C). Elements used as additive to lower temperature the graphitic process include boron, phosphorus, and nitrogen. Boron is known as a graphitization additive, because it accelerates the homogeneous continuous graphitization process of the entire carbon without any formation of specific carbon components such as graphite. In this study, various amounts of boron and PFO (pyrolysis fuel oil, carbon precursor) were used in an attempt to reveal the boron additive effect. Pitch was produced using a boric acid and pyrolysis fuel oil (PFO), and high-temperature carbonization was carried out at 2600 °C. As a result, synthetic graphite exhibiting high crystallinity at a relatively low temperature was produced. The electrochemical performance of several boron-doped and non-doped carbon materials with different structures as anodes in lithium-ion batteries was investigated by a structure analysis.

Anionic Polymerization of Para-Diethynylbenzene: Synthesis of a Strictly Linear Polymer

“…The behavior of boron-containing compounds is of practical interest in the synthesis of various carbon materials from the point of view of creating the necessary intramolecular structure of these materials [ 77 , 78 , 79 , 80 ].…”

“…The highest thermal oxidation stability was observed for samples also treated at 1500 °C ( Figure 14 ). Apparently, this is due to the graphitization of OCF samples due to the inward migration of boron, which is an effective catalyst for graphitization [ 77 , 79 , 84 ].…”

“…The effect was enhanced by the presence of CPA-5 groups in the modifying -C≡CH additive. The behavior of boron-containing compounds is of practical interest in the synthesis of various carbon materials from the point of view of creating the necessary intramolecular structure of these materials [77][78][79][80].…”

“…The highest thermal oxidation was observed for samples also treated at 1500 °C (Figure 14). Apparently, this is due to the graphitization of OCF samples due to the inward migration of boron, which is an effective catalyst for graphitization [77,79,84] . Thus, in the process of heat treatment, thermal decomposition of boron-containing polymer compositions occurs with the formation of intermediate structures and further formation of nitride-boron structures.…”

Review of Boron Compounds in Lithium Batteries: Electrolyte, Anode, Cathode, Separator, and Battery Thermal Management System (BTMS)

“…As well as graphite coating, borate addition during the high-temperature treatment process of synthetic graphite (SG) could lower the required temperature for graphitization [40]. When placing boron in a lattice structure, it was found to act as an electron acceptor; hence, it increased the specific capacity to 437 mAh/g, a level higher than the theoretical maximum of pure graphite at 372 mAh/g [41].…”