【摘要】 通过第一性原理计算研究了嵌入锂/钠后氟化石墨结构的演化过程。计算考虑了单层氟化石墨上和体相氟化石墨中的锂/钠嵌入。与锂的嵌入相比,将钠嵌入氟化石墨(CF)正极中所表现的循环性能更好,这是因为锂–氟间相互作用和钠–氟间相互作用的强度和特点不同。锂和氟之间的相互作用与钠和氟之间的相互作用相比更强且更集中。这种锂–氟之间强烈的库仑吸引作用破坏了F—C,并将氟原子拔出,从而导致在锂嵌入过程中形成单层石墨烯。更多还原

【Abstract】 The structure evolution of fluorinated graphite(CF_x) upon the Li/Na intercalation has been studied by firstprinciples calculations. The Li/Na adsorption on single CF layer and intercalated into bulk CF have been calculated. The better cycling performance of Na intercalation into the CF cathode, comparing to that of Li intercalation, is attributed to the different strength and characteristics of the Li-F and Na-F interactions. The interactions between Li and F are stronger and more localized than those between Na and F. The strong and localized Coulomb attraction between Li and F atoms breaks the C—F bonds and pulls the F atoms away, and graphene sheets are formed upon Li intercalation.更多还原