Improving the performance of paper-based separator for lithium-ion batteries application by cellulose fiber acetylation and metal-organic framework coating

Paper-based separator for lithium-ion battery application has attracted great attention due to its good electrolyte affinity and thermal stability. To avoid the short circuit by the micron-sized pores of paper and improve the electrochemical properties of paper-based separator, cellulose fibers were acetylated followed by wet papermaking and metal-organic framework coating. Due to the strong intermolecular interaction between acetylated cellulose fibers and N,N-dimethylformamide, the resulting separator exhibited compact microstructure. The zeolitic imidazolate framework-8 coating endowed the separator with enhanced electrolyte affinity (electrolyte contact angle of 0°), ionic conductivity (1.26 mS·cm⁻¹), interfacial compatibility (284 Ω), lithium ion transfer number (0.61) and electrochemical stability window (4.96 V). The assembled LiFePO₄/Li battery displayed an initial discharge capacity of 146.10 mAh·g⁻¹ at 0.5 C with capacity retention of 99.71% after 100 cycles and good rate performance. Our proposed strategy would provide a novel perspective for the design of high-performance paper-based separators for battery applications.