添加In3+,Sn4+及SnO2對正極材料LiNi0.8Co0.2O2電化學特性的影響

The effects of adding In3+, Sn4+, and SnO2 on the Electrochemical Properties of LiNi0.8Co0.2O2 Cathode

楊國順(Kuo-shun Yang)

指導教授 ： 林永仁

大同大學/工程學院/材料工程學系所/碩士(2005年)

摘要

LiNi0.8Co0.2O2是以共沉法經800℃熱處理8小時(氧氣氣氛下)的條件下製備。為了改善其較差的電化學循環特性，我使用2種不同的製程嘗試改善它的特性。1種是以doping過渡金屬(如In,Sn離子)，另一種是添加微量的金屬氧化物(如SnO2)。在我的實驗中LiNi0.8Co0.2-xInxO2獲得的衰退率還是較大的，In離子的添加似乎無法改善循環穩定性。而在添加Sn離子的系統中，LiNi0.8Co0.18Sn0.02O2在C/10 rate下能獲得了最高的初比放電容量(181 mAh/g)及循環穩定性(17%)。在添加SnO2的系統中，則是以0.56 wt%的添加量，能獲得一個比未添加時有較好的結果。然而還是以LiNi0.8Co0.18Sn0.02O2有最好的電化學表現。另外也在SEM的觀察下發現到添加Sn離子所獲得的粉末，其粒徑均較小也較為均勻。

關鍵字

鋰鎳鈷氧基 ； 正極材料 ； 鋰離子電池 ； 二氧化錫，添加

並列摘要

LiNi0.8Co0.2O2 powders are prepared by co-precipitation method and heat treatment at 800℃ for 8 hours under O2 atmosphere. In order to improve the electrochemical cycling behavior, I use two processes to modify the properties of the powder. One is doping the transition metal ions such as In or Sn ions to prepare the LiNi0.8Co0.2-xMxO2 powders. The other one is adding SnO2 into the LiNi0.8Co0.2O2 powders. The sample of LiNi0.8Co0.2-xInxO2 with x value of 0.05 has larger initial discharge capacity than LiNi0.8Co0.2O2 cathode, but the capacity fading is also larger. The sample of LiNi0.8Co0.2-xSnxO2 with x value of 0.02 has the largest initial discharge capacity of 181 mAh/g with C/10 rate at 30℃ and shows the best cycling performance (fading rate = 17.1%) than the other cathodes. The sample of SnO2/LiNi0.8Co0.2O2 with 0.56 wt% of SnO2 addition has the larger initial discharge capacity and better capacity fading than LiNi0.8Co0.2O2 cathode. The SEM is used to observe the powder surface and particle sizes. The particle sizes of LiNi0.8Co0.2-xSnxO2 powders are smaller than other powders.

並列關鍵字

adding ； cathode material ； Li ion battery ； LiNi0.8Co0.2O2 ； SnO2

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