Wang Junjie, Wang Yaqing, Yu Ying, Huang Kang, Xu Zhi
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
ACS Appl Mater Interfaces. 2025 Apr 30;17(17):25370-25378. doi: 10.1021/acsami.5c01415. Epub 2025 Apr 15.
Metal-organic frameworks (MOFs) with active sites have been proposed as advanced fillers for fabricating PEO-based composite solid electrolytes. However, there is a great need for the design and synthesis of MOFs with more active sites to further increase the ionic conductivity of solid electrolytes. Herein, rich defect sites are constructed via acid etching to scale up the active sites of MOFs (MIL-88A). The etched MIL-88A (EMIL-88A) materials have more pores and exposed unsaturated metal coordination sites, which can facilitate the dissociation of lithium salt through the metal-anion interaction and lead to an outstanding Li transference number of 0.63. The Fe-O bond formed between metal active sites and PEO can inhibit the crystallization of PEO and provide a fast Li migration pathway, resulting in a high ion conductivity of 4.2 × 10 S cm (60 °C). As a result, assembled Li-Li symmetric batteries show good stability for over 300 h at 0.1 mA cm. The assembled LiFePO full batteries deliver a high reversible capacity of 113.2 mAh g after 250 cycles at 60 °C and 0.5 C. This defect engineering of MOFs offers a promising strategy for PEO-based composite solid electrolytes.
具有活性位点的金属有机框架（MOFs）已被提议作为制造基于聚环氧乙烷（PEO）的复合固体电解质的先进填料。然而，迫切需要设计和合成具有更多活性位点的MOFs，以进一步提高固体电解质的离子电导率。在此，通过酸蚀刻构建丰富的缺陷位点，以扩大MOFs（MIL-88A）的活性位点。蚀刻后的MIL-88A（EMIL-88A）材料具有更多的孔隙和暴露的不饱和金属配位位点，这可以通过金属-阴离子相互作用促进锂盐的解离，并导致出色的锂迁移数为0.63。金属活性位点与PEO之间形成的Fe-O键可以抑制PEO的结晶，并提供快速的锂迁移途径，从而在60°C时产生4.2×10 S cm的高离子电导率。结果，组装的Li-Li对称电池在0.1 mA cm下显示出超过300小时的良好稳定性。组装的LiFePO全电池在60°C和0.5 C下经过250次循环后，提供了113.2 mAh g的高可逆容量。这种MOFs的缺陷工程为基于PEO的复合固体电解质提供了一种有前景的策略。
