A Highly Reversible Room-Temperature Sodium Metal Anode.
A Highly Reversible Room-Temperature Sodium Metal Anode.
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DOI：
10.1021/acscentsci.5b00328
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发表时间：
2015-11-25
影响因子：
18.2
通讯作者：
Cui Y
中科院分区：
文献类型：
--
作者：
Seh ZW;Sun J;Sun Y;Cui Y
由于其低成本和高天然丰度，钠金属是锂离子电池以外储能技术中最有前途的阳极材料之一。然而，室温钠金属阳极在长期镀覆和剥离期间遭受较差的可逆性，这主要是由于形成不均匀的固体电解质界面以及钠金属的枝晶生长。在此，我们报告的第一次，一个简单的液体电解质，六氟磷酸钠在甘醇二甲醚（单，二，和tetraglyme），可以使高度可逆的和非树枝状的电镀剥离的钠金属阳极在室温下。在0.5 mA cm-2下，在300次镀-剥循环中实现了99.9%的高平均库仑效率。发现长期可逆性产生于由氧化钠和氟化钠制成的均匀的无机固体电解质中间相的形成，所述无机固体电解质中间相对电解质溶剂是高度不可渗透的并且有利于非枝晶生长。作为概念验证，我们还展示了使用此类电解质的室温钠硫电池，为下一代钠基储能技术的开发铺平了道路。室温钠金属阳极可以使用甘醇二甲醚中的六氟磷酸钠以高度可逆和非树枝状的方式循环，为下一代钠基电池的开发铺平了道路。
Owing to its low cost and high natural abundance, sodium metal is among the most promising anode materials for energy storage technologies beyond lithium ion batteries. However, room-temperature sodium metal anodes suffer from poor reversibility during long-term plating and stripping, mainly due to formation of nonuniform solid electrolyte interphase as well as dendritic growth of sodium metal. Herein we report for the first time that a simple liquid electrolyte, sodium hexafluorophosphate in glymes (mono-, di-, and tetraglyme), can enable highly reversible and nondendritic plating–stripping of sodium metal anodes at room temperature. High average Coulombic efficiencies of 99.9% were achieved over 300 plating–stripping cycles at 0.5 mA cm–2. The long-term reversibility was found to arise from the formation of a uniform, inorganic solid electrolyte interphase made of sodium oxide and sodium fluoride, which is highly impermeable to electrolyte solvent and conducive to nondendritic growth. As a proof of concept, we also demonstrate a room-temperature sodium–sulfur battery using this class of electrolytes, paving the way for the development of next-generation, sodium-based energy storage technologies. Room-temperature sodium metal anodes can be cycled in a highly reversible and nondendritic manner using sodium hexafluorophosphate in glymes, paving the way for the development of next-generation sodium-based batteries.