细菌纤维素/TiO_2锂离子电池复合隔膜的研究

Study on Bacterial Cellulose/TiO_2 Composite Separators for Lithium-Ion Batteries

利用细菌纤维素(BC)的纳米纤维与纳米TiO_2颗粒进行溶液混合,制备了具有多孔、极性和良好热稳定性的BC/TiO_2锂离子电池隔膜,并对其孔结构、亲液性、热稳定性、电化学稳定性、离子电导率和电池性能循环稳定性等性能进行研究.结果表明,BC/TiO_2复合膜具有三维网状结构、良好吸液性和高温尺寸稳定性.相对于商品化隔膜(Celgard 2325),BC/TiO_2隔膜具有更高的离子电导率,并且随着纳米TiO_2质量分数的增加,离子电导率先升高后降低,当纳米TiO_2质量分数为20.81%时,BC/TiO_2复合膜具有最大的室温离子电导率(1.70×10^(-3)S/cm).BC/TiO_2复合膜作为锂离子电池隔膜时,电池具有较好的循环稳定性和倍率性能.该研究对制备优异热稳定性和离子电导率的锂离子电池隔膜具有指导意义.

Bacterial cellulose（BC）/TiO2 composite membranes with porous,polar and good thermal stability as novelseparator for lithium ion battery are prepared by using TiO2 nanoparticles made by sol-gel method to mix with BC nanofibers.The pore structure,lyophilic performance,thermal stability,electrochemical stability,ionic conductivity and battery cycling stability of the composite membranes are characterized by a variety of techniques.The research results indicate that BC/TiO2 composite membranes have a three-dimensional net structure,good electrolyte absorptivity and dimensional stability at high temperature.Compared to the commercial membrane（Celgard 2325）,BC/TiO2 composite separators have higher ionic conductivity.With the increase of TiO2 mass fraction content,the ionic conductivity increases at first and decreases subsequently.When the content of TiO2 nanoparticles is 20.81%,the BC/TiO2 composite separator has the highest ionic conductivity（1.70 × 10^-3S/cm）.When the composite membranes are used as the separators for lithium ion battery,the battery shows its good cyclic stability and high rate discharge performance.This research has a guiding significance in the preparation of lithium ion battery separator with excellent thermal stability and ionic conductivity.