ZIF-67原位负载纳米纤维素基锂离子电池隔膜的制备及性能研究

Preparation and Properties of ZIF-67 In-situ Loaded Cellulose Nanofibril-based Separator for Lithium-ion Batteries

关键词:  乙酰化纳米纤维素  ZIF-67  隔膜  锂离子电池

Key Words:acetylated cellulose nanofibril  ZIF-67  separator  lithium-ion batteries

摘要:本研究以纳米纤维素（CNF）为原料，经乙酰化、原位负载ZIF-67和浸渍电解液制备出一种新型ZIF-67@乙酰化纳米纤维素（ZIF-67@ACNF）锂离子电池隔膜，系统探讨了ZIF-67的粒径对隔膜结构及性能的影响。结果表明，当ZIF-67的粒径从0.46 μm（ZIF-67₄@ACNF隔膜）减小至0.25 μm（ZIF-67₈@ACNF隔膜）时，隔膜的孔隙率从74.2%减小至52.1%，离子电导率从0.75 mS/cm下降至0.22 mS/cm，界面电阻从112.5 Ω增加至1 115.7 Ω，锂离子迁移数从0.41减小至0.31，电化学稳定窗口从5.1 V减小至4.5 V。采用ZIF-67₄@ACNF隔膜组装电池，在室温、0.5 C的条件下进行电池充/放电测试，初始容量达到159.6 mAh/g，循环200圈后容量保持率达到90%。

Abstract:In this study， cellulose nanofibril （CNF） was acetylated followed by in-situ loading of ZIF-67 and electrolyte impregnation to prepare a novel ZIF-67@acetylated cellulose nanofibril （ZIF-67@ACNF） separator for lithium-ion batteries. The effects of particle size of ZIF-67 on the structure and performance of the separator were systematically investigated. The results showed that as the particle size of ZIF-67 decreased from 0.46 μm （in ZIF-67₄@ACNF separator） to 0.25 μm （in the ZIF-67₈@ACNF separator）， the porosity of the separator reduced from 74.2% to 52.1%， the ionic conductivity decreased from 0.75 mS/cm to 0.22 mS/cm， the interfacial resistance increased from 112.5 Ω to 1 115.7 Ω， the lithium-ion transference number declined from 0.41 to 0.31， and the electrochemical stability window went down from 5.1 V to 4.5 V. The initial capacity of assembled cell by ZIF-67₄@ACNF separator reached 159.6 mAh/g with a capacity retention rate of 90% after 200 cycles at 0.5 C under room temperature.