臺灣博碩士論文加值系統

摘要 本論文之研究的目的有二
：(1)利用硝酸與濃硫酸混合溶液處理石墨材料，增進電池循環壽命。(2)
以鋰蒙脫石添加至石墨電極材料中，增加電池循環壽命。 鋰離子於酸
處理石墨材料中擴散係數，以六分鐘處理之石墨材料擴散係數最
大(1.298*E-7 cm2/s)。充放電測試顯示，酸處理之石墨材料，明顯改善
電池循環性能，其中以酸處理8分鐘者100次充放電循環後之比電容量仍可
維持在259mAh/g以上，而且其比電容量量稍有增加(270 ->295mAh/g)。交
流阻抗測試顯示，石墨電極之鈍態膜於鋰離子嵌入量為x=0.2~0.3
(LixC6)達到較穩定狀態。 鋰蒙脫石具有層狀構造與離子導電性，添
加至同為層狀構造具電子導電性之石墨中修飾石墨電極材料。充放電循環
測試顯示，添加2wt%鋰蒙脫石可降低比電容量衰減速率，前100次充放電
循環之電容量衰減速率由57%降至25%，增加電池循環壽命。關鍵字：鋰蒙
脫石，擴散係數，充放電測試，交流阻抗測試。

Abstract There are two goals of
this thesis : (1) It can increase the cycle life of batteries by
soaking graphite material in the solution that mixing
sulfuricacid and nitric acid; (2) Doping Li-montmorillonite in
the graphite material in order to improve cycle life of
batteries. It has been found that increase the time of acid
treatment the diffusion coefficient of lithium in the graphites
increase, and it reaches the largest value (1.298*E-7 cm2/s) as
graphite treated in 6 minnute. The cycle life of graphite
materials are shown to be improved by pretreatment in acid
media,and the specific capacity retained over 259mAh/g as
graphite being treated in 8 minute at 100th cycle in charge/
discharge cycling test. It can be found from the AC impedance
test, the passivation film of graphite electrode becomemore
stabilized as the content of lithium on graphite in x=0.2~0.3
(LixC6). There are the properties of layer structure and
ionic conductivity of Li-montmorillonite, and doping it in
graphite material which keep with electronicconductivity can
improve the charge/discharge behaviors and increase the
cyclelife of batteries. The decayed rate of specific capacity
before 100th cycle incharge/discharge cycling test has been
decreased from 57% to 25% as the graphite electrode materials
with 2wt% Li-montmorillonite.Keywords: Li-montmorillonite,
diffusion coefficient, charge/discharge test, AC
impedance.