液流电池用多维纳米复合多孔离子传导膜的多尺度设计及性能研究

Vanadium flow battery (VFB) is one of the most promising large-scale energy storage technologies, due to its long life, large capacity, high safety and so forth. At present, perflourinated sulfonated ion exchange membranes, which are the most commonly used membranes in VFBs, suffer from low selectivity and high cost, limiting the practicability and industrialization of VFBs. In order to overcome such issues, the porous membranes were introduced into VFBs to replace traditional ion exchange membranes, which provided a totally new concept for VFB membrane design. Besides, the feasibility and reliability of porous membranes used in VFBs have been verified. However, the investigations on the structure-performance relationship along with the mechanism of ion transport of porous membranes are not deep and systematic enough. Nowadays, the preparation of membrane materials mainly depends on experience, impeding the pervasive utilization of VFBs. Multi-dimensional nanomaterials possess attractive features of tunable morphology and performance, excellent mechanical strength and so on, which were widely used in separation, catalysis, sorption, etc. Moreover, it is unique for ions to transport across the multi-dimensional materials. In this project, multi-dimensional materials with ordered porous channels structure will be introduced into the porous matrixes, to construct the composite porous membranes. Furthermore, theoretical calculation will be used to study the mechanism of ion transport and structure-performance relationship of multi-dimensional materials in VFBs. On the basis of these investigations, high-performance porous membranes with high ion selectivity and proton conductivity will be developed to accelerate the practicability and industrialization of VFBs.

全钒液流电池储能技术（VFB）具有寿命长、规模大、安全可靠等优势，成为规模储能的首选技术之一。目前，VFB用全氟磺酸离子交换膜离子选择性低、价格昂贵，严重阻碍了其实用化和产业化。为此，申请者提出了用多孔离子传导膜来取代传统离子交换膜的概念，证实了其可行性，为VFB隔膜研发开创了一条全新的思路。但目前对多孔离子传导膜的构效关系，离子传输机理等缺乏深入系统研究。膜材料制备更多依赖于经验，严重阻碍了VFB的普及应用。多维纳米材料因其结构可调、功能可控、机械稳定性优良等特点而广泛应用于分离、催化、吸附等领域。此外，离子通常在多维纳米材料中显示出较为独特的传输行为。本项目拟将具有规整孔道结构的多维纳米材料引入到多孔基膜中，构建复合多孔离子传导膜，结合理论计算，研究其在VFB中的离子传输机理和构效关系。以此为基础开发高选择性、高离子传导性多孔离子传导膜材料，推进液流电池产业化进程。

离子传导膜是全钒液流电池（VFB）的关键核心部件之一，其性质和成本直接影响着电池系统的性能和成本。本项目针对目前VFB用离子传导膜中存在的关键科学与技术问题，设计开发出高选择性、高传导性复合离子传导膜材料，并阐明了膜的构效关系和离子传输机理，实现了离子传导膜的结构设计与性能优化。.通过引入多维纳米材料，成功构筑出具有规整结构、尺寸可控的离子传输通道，制备出系列高选择性、高传导性复合离子传导膜。阐明了质子跳跃传递机理和钒离子传输机理：通过调控离子传导膜内离子传输通道，实现了钒离子和质子的高效筛分。因此，所制备复合膜兼具高选择性和高传导性，突破了其选择性和传导率之间的Trade-off效应。其所组装的VFB，在高达260 mA cm-2的电流密度下，能量效率达到80%，是当时报道的最高值。此外，突破了膜材料的规模放大技术，建成膜材料批量化生产线，实现了液流电池用膜材料的批量化。所开发膜材料集成出30 kW级液流电池电堆。其工作电流密度可达235 mA cm-2，能量效率>80%，功率密度提高近1倍。基于开发的高功率密度电堆，集成出MW级系统，并开展了示范应用，推动了液流电池的产业化发展。.相关成果在Energy Environ. Sci.、J. Am. Chem. Soc.、Nat. Commun.、Adv. Mater.、Adv. Energy Mater.、Adv. Funct. Mater.等国外学术期刊发表论文50篇，申请发明专利40件，授权20件。技术完成国内外许可。研究成果获中科院科技促进发展奖和中国石油和化学工业联合会技术发明一等奖等奖励。项目负责人获青山科技奖和科学探索奖。