纤维素非溶剂致相分离法制备锂电池隔膜的研究

Preparation of Lithium Battery Separator by Non-solvent-induced Phase Separation of Cellulose

中文关键词:  再生纤维素  非溶剂致相分离法  锂电池隔膜  碱/尿素体系

Key Words:regenerated cellulose  non-solvent-induced phase separation  lithium battery separator  alkali/urea system

中文摘要:

      本研究采用NaOH/尿素/硫脲溶解体系和非溶剂致相分离法制备再生纤维素锂电池隔膜，并比较其与市售聚烯烃Celgard 2400隔膜、纤维素隔膜的电化学性能。结果表明，再生纤维素锂电池隔膜的孔隙率为56.1%、平均孔径为305 nm，电解液吸液率为339%、保液率为68.9%、离子电导率为1.88 mS/cm；在0.5 C倍率下充放电循环100次后，比容量达156.55 mAh/g，库伦效率高于96%。市售Celgard 2400隔膜的离子电导率为0.43 mS/cm，在0.5 C倍率下进行100次充放电循环测试后，其比容量仅为74.26 mAh/g，库伦效率低于88%。与Celgard 2400隔膜相比，再生纤维素锂电池隔膜具有更高的孔隙率、更好的电解质润湿性、更低的内阻、更快的离子传输速度，以及可再生、环境友好等优点，在锂电池领域具有广阔的应用前景。

Abstract:

      In this study， regenerated cellulose lithium battery separator was prepared by NaOH/urea/thiourea dissolution system and non-solvent-induced phase separation method， and the electrochemical properties of regenerated cellulose lithium battery separator and commercial polyolefin Celgard 2400 separators and cellulose separators were compared. The results showed that the regenerated cellulose lithium battery separator had a porosity of 56.1%， an average pore size of 305 nm， an electrolyte absorption rate of 339%， a liquid retention rate of 68.9%， and an ionic conductivity of 1.88 mS/cm； the specific capacity reached 156.55 mAh/g， and the Coulombic efficiency was higher than 96% after 100 charge/discharge cycles at a rate of 0.5 C. The Celgard 2400 separator had an ionic conductivity of 0.43 mS/cm， and the specific capacity was only 74.26 mAh/g after 100 charge/discharge cycles at a rate of 0.5 C， and the Coulomb efficiency was lower than 88%. Compared with Celgard 2400 separator， the regenerated cellulose lithium battery separator had higher porosity， better electrolyte wettability， lower internal resistance， faster ion transport speed， as well as the advantages of renewability and environmental friendliness， which made the regenerated cellulose lithium battery separator to be a broad application prospect in the field of lithium batteries.