摘要
Aside from the electrolyte, a separator is another important component in lithium-based batteries that has a direct impact on the safety feature and electrochemical performances. To overcome the thermal shrinkage and poor electrolyte affinity of commonly used polyolefin separators, cellulose-based separators are appealing due to their abundant polar functional groups, thermal stability, and environmental friendliness, especially for large-sized and high-energy-density batteries. Herein, a porous three-dimensional (3D) network of polymer cellulose-based separator (denoted as PIC) modified with polyethyleneimine (PEI) and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) was prepared using a non-solvent induced phase separation approach. The lithium metal batteries consisting of a PIC separator can deliver a specific capacity of up to 114 mAh g(-1) even at a high C-rate of 8 C (1.36 A g(-1)) after 300 cycles. Such superior performances of the lithium metal batteries can be attributed to the good wetting ability (390 % electrolyte absorption) and high ionic conductivity (0.754 mS cm(-1)) of the as-prepared PIC separator. More importantly, the introduction of polyethyleneimine as a cross-linking agent significantly improves the mechanical strength of the separator, promotes the uniform deposition of lithium, and compatibility with high voltage (4.4 V) cathode materials LiNi0.8Mn0.1Co0.1O2. This work demonstrates a new strategy for the separator design for high-performance lithium metal battery applications.
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单位南阳理工学院