The development of membranes with rapid and selective ionic transport is imperative for diverse electrochemical energy conversion and storage systems, including fuel cells and flow batteries. However, the practical application of membranes is significantly hindered by their limited conductivity and stability under strong alkaline conditions. Herein, a unique composite membrane decorated with functional Cu2+ cross‐linked chitosan (Cts‐Cu‐M) is reported and their high hydroxide ion conductivity and stability in alkaline flow batteries are demonstrated. The underlying hydroxide ions transport of the membrane through Cu2+ coordinated nano‐confined channels with abundant hydrogen bonding network via Grotthuss (proton hopping) mechanism is proposed. Consequently, the Cts‐Cu‐M membrane achieves high hydroxide ion conductivity with an area resistance of 0.17 Ω cm2 and enables an alkaline zinc‐based flow battery to operate at 320 mA cm−2, along with an energy efficiency of ≈80%. Furthermore, the membrane enables the battery for 200 cycles of long‐cycle stability at a current density of 200 mA cm−2. This study offers an in‐depth understanding of ion transport for the design and preparation of high‐performance membranes for energy storage devices and beyond.

中文翻译：

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用于碱性锌基液流电池的通过纳米限制氢键网络实现高效氢氧根离子传输的壳聚糖复合膜

开发具有快速和选择性离子传输功能的膜对于各种电化学能量转换和存储系统（包括燃料电池和液流电池）至关重要。然而，膜的实际应用因其在强碱性条件下有限的电导率和稳定性而受到严重阻碍。在此，一种独特的复合膜装饰有功能性铜2+报道了交联壳聚糖（Cts-Cu-M），并证明了它们在碱性液流电池中的高氢氧根离子电导率和稳定性。膜的底层氢氧根离子通过 Cu 的传输2+提出了通过 Grotthuss（质子跳跃）机制具有丰富氢键网络的协调纳米限制通道。因此，Cts-Cu-M膜实现了高氢氧根离子电导率，面积电阻为0.17 Ω cm2并使碱性锌基液流电池能够在 320 mA cm 的电流下运行−2，能源效率约为 80%。此外，该隔膜使电池能够在200 mA cm的电流密度下实现200次循环的长循环稳定性−2。这项研究提供了对离子传输的深入了解，有助于设计和制备用于储能设备等的高性能膜。