A bacterial cellulose/Al2O3 nanofibrous composite membrane for a lithium-ion battery separator

The bacterial cellulose (BC)/Al 2 O 3 nanofibrous composite membrane as a lithium-ion battery separator has been successfully prepared by coating Al 2 O 3 on the BC nanofibers through a simple in situ thermal decomposition of Al(NO 3 ) 3  · 9H 2 O. Thermal treatment tests show that the BC/Al 2 O 3 composite membrane is thermally stable at a high temperature of 200 °C while great shrinkage is observed for the commercial PP-PE-PP membrane. Moreover, the BC/Al 2 O 3 membrane is evaluated to have large porosity and excellent electrolyte uptake, consequently giving rise to larger ionic conductivity, lower interfacial resistance as well as better electrochemical stability. The half lithium-ion battery assembled with the BC/Al 2 O 3 separator demonstrates large discharge capacity and good cycling performance, suggesting that the BC/Al 2 O 3 membrane can be used as a lithium-ion battery separator.