纳米二氧化硅/聚酰亚胺涂层改性聚丙烯隔膜

Modified polypropylene separator with nano silicon dioxide /polyimide coating

以聚酰亚胺（PI）作为粘结剂，利用纳米二氧化硅（Si02）颗粒对锂离子电池用聚丙烯（PP）隔膜进行陶瓷改性，得到PP／Si02复合隔膜。通过场发射扫描电镜、热收缩、交流阻抗及充放电实验等方法，对复合隔膜的热性能及电化学性能进行分析。制备的复合隔膜具有良好的耐热收缩性能，纳米颗粒间形成了高度发达的孔隙结构，150oC时的热收缩率仅为1．8％，可提高锂离子电池的安全性。30min涂层复合隔膜组装的LiC002／Li电池，以0．2C充电、0．5C放电，在2．75～4．20V循环，首次放电比容量为140mAh／g，高于PP隔膜组装电池的138mAh／g。

Nano silicon dioxide （ SiO2 ） particle was coated on polypropylene （PP） separator with polyimide （PI） as binder to get modified composite separator. The composite separator was characterized by SEM, thermal shrinkage,A. C. impendance and charge- discharge experiments. The thermal performance of ceramic modified composite separator was fine,the thermal shrinkage at 150 ~C was only 1.8% and the safety of Li-ion battery could be improved. Due to the highly developed porous structure formed by nanopar- ticle, when cycled in 2. 75 - 4. 20 V with 0. 2 C charging,0. 5 C discharging, the initial specific discharge capacity of LiCoOJLi cell assembled with 30 nm coating composite separator was 140 mAh/g,higher than PP separator（ 138 mAh/g）.