Wang Wei,Long Xiangli,Pang Liping,Shen Dawei,Wang Qing
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 LiFePO 4 /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.
Zhenghao Li,Wei Wang,Xinmiao Liang,Jianlin Wang,Yonglin Xu,Wei Li
It is well established that paper-based separators display short-circuit risk in lithium-ion batteries due to their intrinsic micron-sized pores. In this research, we have adjusted pore structure of paper by fiber swelling in liquid electrolyte. Specifically, the paper-based separator is prepared by propionylated sisal fibers through a wet papermaking process. Scanning electron microscope (SEM) and multi-range X-ray nano-computed tomography (CT) images display strong swelling of modified fibers after electrolyte absorption, which can effectively decrease the pore size of separator. Due to the high electrolyte uptake (817 wt%), paper-based separator exhibits ionic conductivity of 2.93 mS cm −1 . 7 Li solid-state NMR spectroscopy and Gaussian simulation reveal that the formation of local high Li + ion concentration in the separator and its low absorption energy with Li + ion (62.2 kcal mol −1 ) is conducive to the ionic transportation. In particular, the assembled Li/separator/LiFePO 4 cell displays wide electrochemical stability window (5.2 V) and excellent cycle performance (capacity retention of 96.6% after 100 cycles at 0.5 C) due to the reduced side reactions as well as enhanced electrolyte absorption and retention capacity by propionylation. Our proposed strategy will provide a novel perspective to design high-performance bio-based separators to boost the development of clean and sustainable energy economy.
危险品化学品经营许可证（带存储）