Lu Xiao-Meng, Wang Haichao, Sun Yiwen, Xu Yi, Sun Weiwei, Wu Yang, Zhang Yifan, Yang Chao, Wang Yong
Department of Chemical Engineering, School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, 200444, Shanghai, People's Republic of China.
Sino-European School of Technology of, Shanghai University, 99 Shangda Road, 200444, Shanghai, People's Republic of China.
Angew Chem Int Ed Engl. 2024 Oct 7;63(41):e202409436. doi: 10.1002/anie.202409436. Epub 2024 Sep 6.
The appearance of disordered lithium dendrites and fragile solid electrolyte interfaces (SEI) significantly hinder the serviceability of lithium metal batteries. Herein, guided by theoretical predictions, a multi-component covalent triazine framework with partially electronegative channels (4C-TATF-CTF) is incorporated as a protective layer to modulate the interface stability of the lithium metal batteries. Notably, the 4C-TATF-CTF with optimized electronic structure at the molecular level by fine-tuning the local acceptor-donor functionalities not only enhances the intermolecular interaction thereby providing larger dipole moment and improved crystallinity and mechanical stress, but also facilitates the beneficial effect of lithiophilic sites (C-F bonds, triazine cores, C=N linkages and aromatic rings) to further regulate the migration of Li and achieve a uniform lithium deposition behavior as determined by various in-depth in/ex situ characterizations. Due to the synergistic effect of multi-component organic functionalities, the 4C-TATF-CTF modified full cells perform significantly better than the common two/three-component 2C-TA-CTF and 3C-TF-CTF electrodes, delivering an excellent capacity of 116.3 mAh g (capacity retention ratio: 86.8 %) after 1000 cycles at 5 C and improved rate capability. This work lays a platform for the prospective molecular design of improved organic framework relative artificial SEI for highly stable lithium metal batteries.
无序锂枝晶和脆弱的固体电解质界面（SEI）的出现严重阻碍了锂金属电池的实用性。在此，在理论预测的指导下，引入一种具有部分电负性通道的多组分共价三嗪框架（4C-TATF-CTF）作为保护层来调节锂金属电池的界面稳定性。值得注意的是，通过微调局部受体-供体官能团在分子水平上具有优化电子结构的4C-TATF-CTF不仅增强了分子间相互作用，从而提供更大的偶极矩并改善结晶度和机械应力，而且还促进了亲锂位点（C-F键、三嗪核、C=N键和芳环）的有益作用，以进一步调节Li的迁移并实现均匀的锂沉积行为，这由各种深入的原位/非原位表征所确定。由于多组分有机官能团的协同作用，4C-TATF-CTF修饰的全电池的性能明显优于常见的二元/三元2C-TA-CTF和3C-TF-CTF电极，在5C下1000次循环后具有116.3 mAh g的优异容量（容量保持率：86.8%），并提高了倍率性能。这项工作为用于高稳定性锂金属电池的改进有机框架相对人工SEI的前瞻性分子设计奠定了平台。
