Influence of the structure of the anion in an ionic liquid electrolyte on the electrochemical performance of a silicon negative electrode for a lithium-ion battery
Influence of the structure of the anion in an ionic liquid electrolyte on the electrochemical performance of a silicon negative electrode for a lithium-ion battery
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DOI：
10.1016/j.jpowsour.2016.10.111
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发表时间：
2017-01
影响因子：
9.2
通讯作者：
K. Yamaguchi;Y. Domi;H. Usui;M. Shimizu;K. Matsumoto;T. Nokami;T. Itoh;H. Sakaguchi
中科院分区：
文献类型：
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作者：
K. Yamaguchi;Y. Domi;H. Usui;M. Shimizu;K. Matsumoto;T. Nokami;T. Itoh;H. Sakaguchi
研究了离子液体电解液中的阴离子对锂离子电池硅负极电化学性能的影响。该电极在四氟硼酸盐基和碳酸亚丙酯基电解液中表现出较差的循环稳定性，而在双(氟磺酰基)酰胺和双(三氟甲磺酰基)胺(TFSA-)电解液中表现出较好的循环性能，其中硅电极在第100次循环中的放电容量超过1000 mA/g−1。认为由FSA-和TFSA-基电解液形成的表面膜有效地抑制了电解液的连续分解。在容量限制测试中，在基于−的电解液中，即使在大约1600次循环后，放电容量仍保持在1000mA/g TFSA 1，这相当于循环寿命几乎是基于TFSA的电解液的两倍。这一结果应由FSA衍生表面膜的高结构稳定性来解释。此外，在6C(21A g−1)的大电流下，FSA基电解液具有更好的倍率性能，放电容量为700A g−1，是TFSA基电解液的7倍。这些结果表明，FSA基离子液体电解质是最有前途的硅基负极候选材料。
We investigated the influence of the anions in ionic liquid electrolytes on the electrochemical performance of a silicon (Si) negative electrode for a lithium-ion battery. While the electrode exhibited poor cycle stability in tetrafluoroborate-based and propylene carbonate-based electrolytes, better cycle performance was achieved in bis(fluorosulfonyl)amide (FSA–)- and bis(trifluoromethanesulfonyl)amide (TFSA–)-based electrolytes, in which the discharge capacity of a Si electrode was more than 1000 mA h g−1at the 100th cycle. It is considered that a surface film derived from FSA–- and TFSA–-based electrolytes effectively suppressed continuous decomposition of the electrolyte. In a capacity limitation test, a discharge capacity of 1000 mA h g−1was maintained even after about the 1600th cycle in the FSA–-based electrolyte, which corresponds to a cycle life almost twice as long as that in TFSA–-based electrolyte. This result should be explained by the high structural stability of FSA–-derived surface film. In addition, better rate capability with a discharge capacity of 700 mA h g−1was obtained at a high current rate of 6C(21 A g−1) in FSA–-based electrolyte, which was 7-fold higher than that in TFSA–-based electrolyte. These results clarified that FSA–-based ionic liquid electrolyte is the most promising candidate for Si-based negative electrodes.