Research and development of a non flammable safety lithium ion battery

商业化的锂离子电池对于能量存储装置具有若干优点，例如高操作电压、高能量密度和相对良好的循环耐久性。然而，在目前的锂离子电池中，使用易燃且容易泄漏的液体电解质是不可避免的。为了提高电池的安全性，许多研究人员一直在开发固体聚合物电解质。但是，电解质的固化严重影响了电解质中离子的迁移率，不能得到具有实用性能的聚合物电池。本项目以开发具有良好充放电性能的真正安全的锂离子聚合物电池为目标，将开发一种具有高离子导电性和不可燃性的聚合物凝胶的新型固体聚合物电解质。我们提出了一种新的锂凝胶-聚合物电池设计，用由溶解在离子液体中的锂盐组成的（LILP）复合材料制造（二元Li-IL）和超高分子量离子液体聚合物（ILP）。该聚合物的分子量超过100万，是通过一种新型的离子液体单体，N，N-二乙基-N-（2-甲基丙烯酰基乙基）-N-甲基铵双（三氟甲基磺酰基）酰亚胺（DEMM-TFSI）的本体自由基聚合制备的。该聚合物可以在仅5wt%的浓度下形成二元Li-IL固体。我们选择了高功率活性电极材料，并将其与LILP系统相结合。与传统的锂聚合物电池相比，示范无蒸汽电池具有更高的放电性能：在40 ℃下，它在3C电流下保持83%的放电容量，并且具有相对良好的循环性能。这是第一次报告的知识，一个锂离子电池与LILP系统执行，在电池性能和循环耐久性方面，在实际应用的水平。

Commercialized lithium ion batteries have several advantages for the energy storage devices, such as a high operating voltage, a high energy density and relatively good cycle durability. However, the use of a flammable and easily leaking liquid electrolyte is unavoidable in the present lithium ion cells. Many researchers have been developing the solid polymer electrolyte in order to raise safety of cells. However, the ionic mobility in electrolyte is greatly spoiled by the solidification of electrolyte, and the polymer battery which has practical performance is not obtained. In this project, aiming to develop a truly safe Li ion polymer cell with a good charge and discharge performance, we will develop a novel solid polymer electrolyte which has high ion-conductive and non-flammable polymer gel.We present a new design of a lithium gel-polymer battery, fabricated with a (LILP) composite consisting of a lithium salt dissolved in an ionic liquid (binary Li-IL) and an ultra high molecular weight ionic liquid polymer (ILP). This polymer, with a Mw of over a million, was prepared by the bulk radical polymerization of a novel ionic liquid monomer, N, N-diethyl-N- (2-mthacryloylethyl)-N-methylammonium bis (trifluoromethylsulfonyl) imide (DEMM-TFSI). The polymer could form a binary Li-IL solid at a concentration of only 5 wt%. We selected high power-active electrode materials, and combined them with the LILP system. The demonstration vapor-free cell had a higher discharge performance than a conventional lithium polymer battery: at 40℃, it retained 83% of its discharge capacity at a 3C current, and relatively good cycle performance. This is the first report of to knowledge that a lithium ion cell with a LILP system performed, in terms of cell performance and cycle durability, at a level of practical utility.