Intrinsically high efficiency sodium metal anode
Intrinsically high efficiency sodium metal anode
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DOI：
10.1007/s11426-020-9808-6
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发表时间：
2020-08
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影响因子：
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通讯作者：
Yifang Zhang;Qiuwei Shi;Y. Zhong;Hailiang Wang
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文献类型：
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作者：
Yifang Zhang;Qiuwei Shi;Y. Zhong;Hailiang Wang
钠金属的有效镀/剥离是任何可充电钠金属电池稳定运行的关键。然而，在使用具有大量过量钠储备的厚钠电极进行电化学测量时，经常被忽视或误解。在此，我们报告了在开发更实用的可在100%深度下有效循环的容量控制的Na金属电极的两个关键方面，这在以前的研究中通常被忽视。我们发现，普通碳酸盐电解质会引起严重的副反应和高度不可逆的Na电镀/剥离，而不含任何添加剂的醚电解质支持厚的Na金属电极，其平均库仑效率高达99.6%，循环超过300次。我们进一步表明，要在薄的Na金属电极上实现如此高的效率，必须确保薄Na层与Cu集流器之间的强粘附，我们通过引入Au中间层来解决这个问题。由此产生的可转移薄金属钠电极可实现高能量密度、高效率和合理稳定循环的Na∥Na3V2(PO4)3电池。
Efficient plating/stripping of Na metal is critical to stable operation of any rechargeable Na metal battery. However, it is often overlooked or misunderstood in electrochemical measurements using thick Na electrodes with large excess of Na reserves. Herein, we report two crucial aspects, which have generally been ignored in previous studies, in the development of more practical capacity-controlled Na metal electrodes that can be efficiently cycled at 100% depth. We find that common carbonate electrolytes induce severe side reaction and highly irreversible Na plating/stripping, whereas ether electrolytes without any additive support thick Na metal electrodes operating at a high average Coulombic efficiency of 99.6% for over 300 cycles. We further show that to realize such high efficiency in thin Na metal electrodes, it is necessary to ensure strong adhesion between the thin Na layer and the Cu current collector, which we solve by introducing an Au interlayer. The resulting transferable thin Na metal electrodes enable high-energy-density, high-efficiency and reasonably stable-cycling Na∥Na3V2(PO4)3batteries.