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

The bacterial cellulose (BC)/Al2O3 nanofibrous composite membrane as a lithium-ion battery separator has been successfully prepared by coating Al2O3 on the BC nanofibers through a simple in situ thermal decomposition of Al(NO3)3 · 9H2O. Thermal treatment tests show that the BC/Al2O3 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/Al2O3 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/Al2O3 separator demonstrates large discharge capacity and good cycling performance, suggesting that the BC/Al2O3 membrane can be used as a lithium-ion battery separator.