基于仿生离子通道的智能调控型微纳米多孔电池隔膜材料的制备及研究

High-energy-density, high-rate and stable electrochemical batteries have been a long-term pursuit, and particularly the lithium-sulfur battery has attracted attention for its high energy density (2600 W h/kg). However, the electrochemical intermediate polysulfides are solvable in the electrolyte, shuttle through the separator and reach the lithium anode and have parasitic chemical reactions, which lead to quick capacity decay. Moreover, when the cell is operated at high rate, redundant heat can be generated and melts the separator, which can cause short circuit of the cell and safety issue. Inspired by the ionic selectivity of biological ionic channels, in this project, we will design a novel smart responsive separator, which will be applied in a battery system. Functional macromolecules will be grafted onto porous membranes through physical or chemical methods, in order to prepare thermo-responsive cell separators to improve the safety level of a battery. Meanwhile, we will graft macromolecules with negative charge on to the membrane to deter the polysulfides from transporting through the membrane, therefore we can get safe, high-capacity, long-life lithium sulfur batteries. In this project, by combining nanoscience and technology and energy storage devices, we aim to pave a new way for designing novel, safe, high-performance energy materials and also to explore new ideas and concepts for new energy materials.

高能量密度、高速率及高稳定性电池研发一直是热点研究领域，其中锂硫电池凭借其极高的理论能量密度引起广泛关注。但由于多硫离子穿梭效应，多硫离子穿过电池隔膜时沉积在锂电极，导致锂硫电池容量快速衰减；并且在高速率、大功率使用时，电池隔膜容易因热短路，存在安全隐患，极大地限制锂硫电池的功能发挥。为解决这些问题，本项目从电池整体结构考虑，受生物离子通道的离子选择性及开关性启发，设计了新型的智能调控型电池隔膜：通过改变微纳米多孔膜的内部电荷特征，或者将带负电荷的高分子接枝到微纳米孔道，阻止多硫离子穿过电池隔膜，保证电池的高容量和高能量；同时通过物理、化学改性方法，将功能性高分子接枝到微纳米多孔膜中，制备低温开、高温关的智能响应性电池隔膜，以提高电池的安全稳定性，获得高容量长循环寿命的安全锂硫电池。本项目将纳米技术应用到能源器件中，打破传统的材料的局限，为设计制备新型、安全的高性能材料提供新思路和新原理。

高能量密度、高速率及高稳定性电池研发一直是热点研究领域，其中锂硫电池凭借其 极高的理论能量密度引起广泛关注。但由于多硫离子穿梭效应，多硫离子穿过电池隔膜时 沉积在锂电极，导致锂硫电池容量快速衰减；并且在高速率、大功率使用时，电池隔膜容 易因热短路，存在安全隐患，极大地限制锂硫电池的功能发挥。为解决这些问题，本项目 从电池整体结构考虑，受生物离子通道的离子选择性及开关性启发，设计了新型的离子聚合物为基础的三维多孔膜集成的电极。鉴于该多孔膜的优异的离子选择性，多硫离子作为能量物质被完美的阻隔在正极，减少了能量损失；同时锂离子快送从锂负极传输到硫正极，减少了电解质和界面的阻力；这些保证了锂电池的快速充放电，且长时间的实现了能源物质不衰减。