Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Sciences, Wuhan University , Wuhan 430072, China.
Hubei Collaboration Innovation Center of Non-power Nuclear Technology , Xianning 437100, China.
ACS Appl Mater Interfaces. 2017 Aug 9;9(31):25970-25975. doi: 10.1021/acsami.7b05535. Epub 2017 Jul 26.
The separator is a critical component of lithium-ion batteries (LIBs), which not only allows ionic transport while it prevents electrical contact between electrodes but also plays a key role for thermal safety performance of LIBs. However, commercial separators for LIBs are typically microporous polyolefin membranes that pose challenges for battery safety, due to shrinking and melting at elevated temperature. Here, we demonstrate a strategy to improve the thermal stability and electrolyte affinity of polyethylene (PE) separators. By simply grafting the vinylsilane coupling reagent on the surface of the PE separator by electron beam irradiation method and subsequent hydrolysis reaction into the Al solution, an ultrathin AlO layer is grafted on the surface of the porous polymer microframework without sacrificing the porous structure and increasing the thickness. The as-synthesized AlO ceramic-grafted separator (AlO-CGS) shows almost no shrinkage at 150 °C and decreases the contact angle of the conventional electrolyte compared with the bare PE separator. Notably, the full cells with the AlO-CGSs exhibit better cycling performance and rate capability and also provide stable open circuit voltage even at 170 °C, indicating its promising application in LIBs with high safety and energy density.
隔板是锂离子电池（LIBs）的关键组成部分，它不仅允许离子传输，同时防止电极之间的电接触，而且对 LIBs 的热安全性能起着关键作用。然而，商用的 LIBs 隔板通常是微孔聚烯烃膜，由于在高温下收缩和熔化，给电池安全带来了挑战。在这里，我们展示了一种提高聚乙烯（PE）隔板热稳定性和电解质亲和性的策略。通过简单地用电子束辐照方法在 PE 隔板表面接枝乙烯基硅烷偶联试剂，然后在 Al 溶液中进行水解反应，在多孔聚合物微框架的表面接枝了一层超薄的 AlO 层，而不会牺牲多孔结构并增加厚度。合成的 AlO 陶瓷接枝隔板（AlO-CGS）在 150°C 时几乎没有收缩，与裸 PE 隔板相比，降低了常规电解质的接触角。值得注意的是，用 AlO-CGS 组装的全电池具有更好的循环性能和倍率性能，即使在 170°C 时也能提供稳定的开路电压，表明其在具有高安全性和能量密度的 LIBs 中有很好的应用前景。
