Zhang Qi, Liu Zewen, Song Xiaosheng, Bian Tengfei, Guo Zhijie, Wu Donghai, Wei Jun, Wu Sixin, Zhao Yong
Key Lab for Special Functional Materials of Ministry of Education; National, Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, School of Materials Science and Engineering, Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng, 475004, P. R. China.
Angew Chem Int Ed Engl. 2023 Jul 24;62(30):e202302559. doi: 10.1002/anie.202302559. Epub 2023 Jun 16.
Polymer based quasi-solid-state electrolyte (QSE) has attracted great attention due to its assurance for high safety of rechargeable batteries including lithium metal batteries (LMB). However, it faces the issue of low ionic conductivity of electrolyte and solid-electrolyte-interface (SEI) layer between QSE and lithium anode. Herein, we firstly demonstrate that the ordered and fast transport of lithium ion (Li ) can be realized in QSE. Due to the higher coordination strength of Li on tertiary amine (-NR ) group of polymer network than that on carbonyl (-C=O) group of ester solvent, Li can diffuse orderly and quickly on -NR of polymer, significantly increasing the ionic conductivity of QSE to 3.69 mS cm . Moreover, -NR of polymer can induce in situ and uniform generation of Li N and LiN O in SEI. As a result, the Li||NCM811 batteries (50 μm Li foil) with this QSE show an excellent stability of 220 cycles at ≈1.5 mA cm , 5 times to those with conventional QSE. LMBs with LiFePO can stably run for ≈8300 h. This work demonstrates an attractive concept for improving ionic conductivity of QSE, and also provides an important step for developing advanced LMB with high cycle stability and safety.
基于聚合物的准固态电解质（QSE）因其确保包括锂金属电池（LMB）在内的可充电电池的高安全性而备受关注。然而，它面临着电解质离子电导率低以及QSE与锂负极之间的固体电解质界面（SEI）层的问题。在此，我们首次证明锂离子（Li⁺）在QSE中可以实现有序且快速的传输。由于Li⁺在聚合物网络的叔胺（-NR₂）基团上的配位强度高于其在酯溶剂的羰基（-C=O）基团上的配位强度，Li⁺可以在聚合物的-NR₂上有序且快速地扩散，显著提高QSE的离子电导率至3.69 mS cm⁻¹。此外，聚合物的-NR₂可以诱导在SEI中原位且均匀地生成Li₃N和LiNO₂。结果，采用这种QSE的Li||NCM811电池（50 μm锂箔）在≈1.5 mA cm⁻²下表现出220次循环的优异稳定性，是采用传统QSE电池的5倍。配备LiFePO₄的LMB可以稳定运行约8300小时。这项工作展示了一种提高QSE离子电导率的有吸引力的概念，也为开发具有高循环稳定性和安全性的先进LMB迈出了重要一步。
