自组装聚吡咯纳米线在锂金属电池中的应用
2021-07-01吴海江何世杰刘志勇黄宇翔刘毅
吴海江 何世杰 刘志勇 黄宇翔 刘毅
摘要:聚吡咯作为优良的导电聚合物,其具备环境稳定性好、导电率高、制备简便等优点,已经在高分子导线、电子和光学器件、防腐材料等各方面广泛应用。本文以吡咯单体、盐酸(HCl)、十六烷基三甲基溴化铵(CTAB)和过硫酸铵(APS)为基底,利用化学聚合法形成的高粘性网状薄膜,探讨其作为锂金属负极的电化学性能;利用扫描电子显微镜(SEM)、红外光谱对其进行了形貌和成分的表征。结果显示:试验最佳的反应条件为反应温度0-5℃,反应时间4h。通过对成膜后的聚吡咯进行电化学性能测试,在1mA/cm2-1mAh/cm2的电流密度下,库伦效率高达97.1%。
关键词:聚吡咯;化学聚合法;锂金属电池
Abstract: As an excellent conductive polymer, polypyrrole has the advantages of good environmental stability, high conductivity, and easy preparation. It has been widely used in polymer wires, electronic and optical devices, and anti-corrosion materials.This article uses pyrrole monomer, hydrochloric acid (HCl), cetyltrimethylammonium bromide (CTAB) and ammonium persulfate (APS) as the base, and uses a high-viscosity network film formed by chemical polymerization to explore its use as lithium Electrochemical performance of metal anode.The morphology and composition were characterized by scanning electron microscope (SEM) and infrared spectroscopy.The results showed that the best reaction conditions in the experiment were the reaction temperature of 0-5°C and the reaction time of 4h. Through the electrochemical performance test of the polypyrrole after film formation, the coulombic efficiency is as high as 97.1% at a current density of 1mA/cm2-1mAh/cm2.
Keywords: polypyrrole; chemical polymerization method; lithium metal battery
锂金属由于具有极高的理论比容量(3860mAh/g),较低的而密度和最低的电势(-3.4V,相对于标准氢电极),是成为高比能锂电池的理想材料[1-3]。随着便携式电子产品的广泛应用,传统锂离子电池的能量密度已经接近极限,锂金属电池的高能量密度吸引了人們的关注,但锂枝晶的存在是限制锂金属电池发展最关键的问题[4-6]。锂枝晶是在充放电过程中,由于电极表面产生的不均匀电场,锂金属在电场作用下持续电镀/剥离在固定位置堆积,从而形成树枝状的枝晶[7-8]。锂枝晶会随着充放电的持续进行不断生长,破坏表面的固体电解质界面膜(SEI),致使裸露的锂枝晶与电解液发生反应,并且脱落形成“死锂”[9]。锂枝晶的持续生长还会刺穿隔膜导致电池发生短路甚至爆炸引发安全事故,破坏电池的循环稳定性[10]。……
