A new approach to very high lithium salt content quasi-solid state electrolytes for lithium metal batteries using plastic crystals
A new approach to very high lithium salt content quasi-solid state electrolytes for lithium metal batteries using plastic crystals
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DOI：
10.1039/c9ta11175a
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发表时间：
2019-11-28
影响因子：
11.9
通讯作者：
Pringle, Jennifer M.
中科院分区：
文献类型：
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作者：
Al-Masri, Danah;Yunis, Ruhamah;Pringle, Jennifer M.
虽然锂金属的高能量密度长期以来一直是锂金属电池发展的强大驱动力，但在安全实用的设备中利用全部理论容量需要在电解质设计方面取得重大进展。准固态电解质的使用对于提高电池的安全性、抑制锂枝晶的生长和延长电池寿命都有很大的好处。有机离子塑料晶体（OIPCs）是一类独特的无序固体，可以支持高离子电导率和锂离子迁移率。直到最近，OIPCs主要用作基体材料，并且只加入低浓度的锂盐掺杂。在这里，我们报道了一种非常高锂含量的电解质，其中含有90 mol%的锂二（氟磺酰基）亚胺，Li[FSI]，结合10 mol%的导电吡啶FSI基OIPC。所得的准固态电解质在30℃下的电导率为0.24 mS cm(-1)，支持稳定的锂电化学反应，锂离子转移数为0.68。在0.1 mA cm（-2）下，对称的Li|锂电池循环100小时。这展示了一种设计更安全的准固态电解质的新方法，该电解质具有高锂含量和优异的电化学和传输性能。
While the high energy density of lithium metal has long been a strong driver for the development of lithium metal batteries, harnessing the full theoretical capacity in a safe, practical device requires significant advances in electrolyte design. The use of quasi-solid state electrolytes can be greatly beneficial for increasing safety, suppressing the growth of lithium dendrites and prolonging cell lifetime. Organic ionic plastic crystals (OIPCs) are a unique class of disordered solid that can support high ionic conductivities and lithium ion mobility. Until recently, OIPCs were used primarily as matrix materials and incorporated only low dopant concentrations of lithium salts. Here we report a very high lithium content electrolyte containing 90 mol% lithium bis(fluorosulfonyl)imide, Li[FSI], combined with 10 mol% of a conductive pyrrolidinium FSI-based OIPC. The resultant quasi-solid state electrolyte achieves a conductivity of 0.24 mS cm(-1) at 30 degrees C, supports stable lithium electrochemistry and has a very good lithium ion transference number of 0.68. Symmetrical Li|Li cell cycling is demonstrated at 0.1 mA cm(-2) for 100 hours. This showcases a new approach for designing safer quasi-solid state electrolytes with high lithium content and excellent electrochemical and transport properties.