聚乙烯基耐高温锂电池隔膜的制备及表征

Preparation and characterization of PE-based thermal-resistant separator for lithium-ion batteries

以聚乙烯(PE)微孔膜为基膜,利用简单的浸渍涂覆法在其表面复合聚偏氟乙烯(PVDF)功能层,并用碱液对功能层进行处理,获得复合膜。对所制备复合膜的形貌、结构、吸液性和耐热性等基本性能进行表征,并对该隔膜进行电池充放电性能测试。结果表明,相比PE基膜,复合膜具有更加发达的表面网状孔结构,该多孔结构显著提升了隔膜的电解液性能,其吸液率达到165%,较PE膜提高近50%。同时,该隔膜显示出较好的耐热性,如经过130℃、60 min的热处理后其热收缩率只有1.5%。鉴于上述优良特性,该复合膜装配的锂离子电池显示出良好的循环容量保持性和倍率放电性能。

Poly(vinylidene fluoride)(PVDF)functional layer was coated on the surface of commercial PE separator by dip-coating method and investigated in lithium-ion batteries.Systematical investigations including morphology characterization,contact angle testing,electrolyte wettability and thermal resistance testing were carried out.The results demonstrate that compared to the PE separator,the composite separator shows well developed porous structure,which can enhance the electrolyte wettability of the separator.The electrolyte uptake of the PVDF/PE composite separator is up to165%,and the thermal shrinkage ratio is only1.5%after heat treatment for60min at130℃.Based on the above advantages,the PVDF/PE separator exhibits better electrochemical performance,such as the rate discharge capability and cycling performance.