粒度对石墨负极材料嵌锂性能的影响

研究了不同粒径（13～80 μm）石墨材料作为锂离子电池负极材料的嵌锂性能.结果表明，石墨粒度大小对嵌锂性能有明显影响，石墨的不可逆容量随着粒径的减小而逐渐增大，当粒径从80 μm减小到13 μm时，其不可逆容量增大了10％.而对可逆容量来说，随着粒径的减小，可逆容量逐渐增大;当粒径减小到20 μm时，可逆容量达到最大;再进一步减小石墨颗粒的粒径，可逆容量则随之减小.这表明石墨颗粒过大或过小都不利于锂离子的可逆脱嵌，只有合适的粒度才能最大限度地可逆脱嵌锂离子.根据不同粒度石墨的比表面的变化趋势，阐述了嵌锂性能随粒度变化的原因.

Effect of Particle Size on Lithium Intercalation Performance of Graphite Anode

Artificial graphite samples with different particle size ranging from 13 to 80 μm were prepared by sieving method. The lithium intercalation performances of these samples were investigated. The results showed that the particle size had distinct effect on lithium intercalation performances of graphite. When particle size of graphite decreased gradually from 80 μm to 13 μm, the irreversible capacity loss of graphite increased about 10％. However, the reversible capacity increased with the decrease of particle size until the latter reached 20 μm with which the graphite had the highest capacity. When the particle size decreased from 20 μm, the reversible capacity decreased also. It suggested that neither large nor small graphite particle is suitable for reversible lithium intercalation. The medium graphite particles have the optimum reversible capacity. The Brunauer-Emmett-Teller (BET) surface area was measured and it increased with the decrease of particle size. This trend could explain the change of lithium intercalation performances of graphite with particle size.