Improved electrode reversibility of anionic redox with highly concentrated electrolyte solution and aramid-coated polyolefin separator
Improved electrode reversibility of anionic redox with highly concentrated electrolyte solution and aramid-coated polyolefin separator
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使用高浓度电解质溶液和芳纶涂层聚烯烃隔膜提高阴离子氧化还原的电极可逆性
DOI：
10.1039/d3ya00066d
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Yabuuchi Naoaki
中科院分区：
文献类型：
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作者：
Shimada Nanaka;Ugata Yosuke;Nishikawa Satoshi;Shibata Daisuke;Ohta Toshiaki;Yabuuchi Naoaki
由丰富的元素制成的高容量电极材料是开发具有成本效益的储能应用所必需的。一种新兴的新化学涉及到一系列具有阳离子无序岩盐结构的电极材料，而无序结构的锂过量和锰基氧化物是这一目的的有吸引力的候选者。这些电极材料通过阳离子/阴离子氧化还原获得了大的可逆容量。然而，在碳酸盐基电解质溶液中，阴离子氧化还原的可逆性不足导致的可循环性在实际应用中是不可接受的。本文中，由LiN(SO2F)2和碳酸二甲酯组成的高浓度电解质显著改善了电极的可逆性。采用芳纶包覆聚烯烃膜有效地解决了使用高粘度浓电解质时存在的浓电解质对孔隙小的聚烯烃分离器不润湿性的实际问题。用浓电解质溶液和芳酰胺包覆分离器对纳米级Li1.14Ti0.29Mn0.57O2进行x射线吸收光谱分析，结果清楚地证明了阴离子氧化还原的可逆性的提高与氧损失的抑制有关。这些发现显示了未来开发不含非丰富镍/钴离子的高能电池应用的可能性。
High-capacity electrode materials made of abundant elements are necessary to develop cost-effective energy storage applications. An emerging new chemistry has involved a series of electrode materials with a cation-disordered rock salt structure, and Li-excess and Mn-based oxides with disordered structures are attractive candidates for this purpose. Large reversible capacities for these electrode materials are obtained through both cationic/anionic redox. However, cyclability associated with insufficient reversibility of anionic redox in carbonate-based electrolyte solutions is not acceptable for practical applications. Herein, a significant improvement of electrode reversibility was achieved with highly concentrated electrolyte consisting of LiN(SO2F)2 and dimethyl carbonate. A practical problem when using high-viscosity concentrated electrolyte, i.e., non-wettability of concentrated electrolyte to polyolefin separators with small pores, was also effectively solved by using an aramid-coated polyolefin membrane. The improvement of reversibility for anionic redox associated with the suppression of oxygen loss, was clearly demonstrated by the results of X-ray absorption spectroscopy of nanosized Li1.14Ti0.29Mn0.57O2 with the concentrated electrolyte solution and aramid-coated separator. These findings have shown the future possibility of developing applications of high-energy batteries without ions of non-abundant nickel/cobalt.