Composite nanofiber membranes of bacterial cellulose/halloysite nanotubes as lithium ion battery separators

Composite nanofiber membranes comprising bacterial cellulose (BC) and halloysite nanotubes (HNTs) were prepared by vacuum filtration. The tensile strength and ionic conductivity of the nanofiber membranes were improved by the blending of HNTs. The BC/HNTs nanofiber membrane with m(BC): m(HNTs) = 150: 1 (denoted as BC/HNTs-150) exhibited superior tensile strength (84.4 MPa), high porosity (83.0%), outstanding thermal stability as well as good electrolyte retention (369% electrolyte uptake). In addition, the BC/HNTs-150 membrane delivered a higher ionic conductivity (5.13 mS cm−1) than that of the BC (2.88 mS cm−1) and commercial PP–PE–PP (2.05 mS cm−1) separators. The battery containing the BC/HNTs-150 separator also showed better capacity (162 mAh g−1) and cycling property (95% after 100 cycles) than the battery using the BC separator, demonstrating the BC/HNTs composite membranes to be hopeful candidates used in high-performance lithium-ion batteries.