Aramid nanofiber/bacterial cellulose composite separators for lithium-ion batteries.

Aramid nanofibers (ANFs) are expected to serve as new nanoscale building blocks which could improve both the mechanical performance and ionic conductivity of bacterial cellulose (BC) membranes due to their high interfacial bonding, matching of fiber size and the polar aramid groups in ANFs. Herein, composite membranes of BC and ANFs with different ANFs loadings of 2%, 4%, 6% and 8% were prepared by a traditional paper-making method after homogeneous mixing. The achieved membranes with relatively low ANFs loadings exhibited the increased tensile strength and ionic conductivity. The Li/LiFePO4 half-cells based on the 2%ANFs/BC separator demonstrated the best electrochemical performance (including discharge capacity, C-rate capability and cycling stability). Thus, the proposed ANFs/BC separators are a promising candidate for high-performance Li-ion batteries.