High-efficient multifunctional electrochemical membrane for lithium polysulfide redox flow batteries
High-efficient multifunctional electrochemical membrane for lithium polysulfide redox flow batteries
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DOI：
10.1016/j.memsci.2021.119539
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发表时间：
2021-10
影响因子：
9.5
通讯作者：
Tongshuai Wang;Xiaofeng Wang;A. Pendse;Yuechen Gao;Kun Wang;Chulsung Bae;Sangil Kim
中科院分区：
文献类型：
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作者：
Tongshuai Wang;Xiaofeng Wang;A. Pendse;Yuechen Gao;Kun Wang;Chulsung Bae;Sangil Kim
基于多硫化锂（Li-PS）化学的氧化还原液流电池（RFB）为大规模储能和电动汽车提供了巨大的机会，因为与传统液流电池相比，它们使用丰富的原材料和更高的能量密度。然而，为了成功地实施Li-PS RFB，必须解决与PS物质通过膜分离器的交叉有关的问题。在这项工作中，我们展示了一种简便的方法，用于制造一种新型的多功能电化学膜（mECM）组成的有机离子交换膜与多孔碳纳米管层和氮化硼层增强。这种合理的设计赋予了膜在有机电解质中显著的离子选择性和尺寸稳定性，导致大大增强的Li+/PS离子选择性，其超过了商业聚烯烃隔膜（即，Celgard 2325）的三个数量级。具有mECM的Li-PS RFB表现出稳定的电化学性能（40次循环后每循环0.05%容量衰减），在0.75 ℃下100次循环后的容量保持率为78%，而具有Celgard 2325膜的参比电池迅速失去其容量（每循环0.33%容量衰减，100次循环时为33%容量）。我们的研究结果强烈表明，mECM具有高的Li+/PS离子选择性，是一种有前途的膜分离器，用于开发高性能的Li-PS RFB系统。
Redox flow batteries (RFBs) based on lithium polysulfide (Li-PS) chemistry present great opportunities for large-scale energy storage and electric vehicles because of their use of abundant raw materials and their higher energy density compared with traditional flow batteries. However, to successfully implement Li-PS RFBs, issues related to the crossover of PS species through a membrane separator must be resolved. In this work, we demonstrate a facile method for fabricating a novel multifunctional electrochemical membrane (mECM) consisting of an organic ion exchange membrane reinforced with a porous carbon nanotube layer and a boron nitride layer. This rational design endows the membrane with remarkable ion selectivity and dimensional stability in organic electrolyte, leading to a greatly enhanced Li+/PS ion selectivity, which exceeds that of a commercial polyolefin separator (i.e., Celgard 2325) by three orders of magnitude. A Li-PS RFB with the mECM exhibited stable electrochemical performance (0.05% capacity decay per cycle after 40 cycles) with 78% capacity retention over 100 cycles at 0.75C, while a reference cell with a Celgard 2325 membrane rapidly lost its capacity (0.33% capacity decay per cycle and 33% capacity at 100 cycles). Our results strongly suggest that the mECM with its high Li+/PS ion selectivity is a promising membrane separator for developing high-performance Li-PS RFB systems.