Cellulose microspheres enhanced polyvinyl alcohol separator for high-performance lithium-ion batteries

Separators typically play an important role in enhancing the electrochemical performance of lithium-ion bat-teries (LIBs), while the preparation of separators suffers good electrochemical performance and high stability. In this study, regenerated porous cellulose microspheres (RCM) were innovatively fabricated and the biodegradable RCM/Polyvinyl alcohol (PVA) separators were successfully prepared through simple mixing and solvent sub-stitution. Interestingly, the RCM with rich carboxylic groups, not only function as nanofillers that increases the strength properties of the three-dimensional porous network, but also enhances Li+ transfer (due to the -COO -and Li+ interactions), resulting in outstanding Li+ transference number (0.54) of the RCM/PVA separator. In addition, the RCM/PVA separator shows excellent thermal stability and high liquid absorption rate (481.25 %). The LiFePO4/3 % RCM-HCl/PVA/Li cell displayed a high discharge capacity of 152.6 mAh center dot g- 1 after 200 cycles at 1C. This work provides a new light on the fabrication of biodegradable separators for LIBs via a novel and cost-effective strategy.