Li Zihao, Ji Wenyan, Wang Tian-Xiong, Zhang Yunrui, Li Zhen, Ding Xuesong, Han Bao-Hang, Feng Wei
School of Material Science and Engineering, Tianjin University, Tianjin 300072, China.
CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
ACS Appl Mater Interfaces. 2021 May 19;13(19):22586-22596. doi: 10.1021/acsami.1c04517. Epub 2021 May 5.
Lithium (Li) metal anodes are regarded as prospective anode materials in next-generation secondary lithium batteries due to their ultrahigh theoretical capacities and ultralow potentials. However, inhomogeneous lithium deposition and uncontrollable growth of lithium dendrites always give rise to the low lithium utilization, rapid capacity fading, and poor cycling performance. Herein, we design the lithiophilic covalent organic frameworks (COFs) containing preorganized triazine rings and carbonyl groups as the multifunctional interlayer in lithium metal batteries (LMBs). Triazine rings rich in lone pair electrons can act as the donor attracting Li ions, and carbonyl groups serve as Li-anchoring sites effectively coordinating Li ions. These periodic arranged subunits significantly guide uniform Li ion flux distribution, guarantee smooth Li deposition and less lithium dendrite formation. Consequently, the symmetric batteries with COF interlayers exhibit an extraordinary cycling stability for more than 2450 and 1000 h with ultralow polarization voltage of about 12 and 14 mV at 0.5 and 1.0 mA cm. Coupling with sulfur (S) cathodes and LiFePO (LFP) cathodes, the full cells also demonstrate superb energy density achievement and rate performance. With introducing lithiophilic COFs interlayers, the Li-LFP batteries exhibit high capacity of 150 mAh g and 86% capacity retention after 450 cycles at 0.5 C.
锂（Li）金属负极因其超高的理论容量和超低的电位，被视为下一代二次锂电池中有前景的负极材料。然而，锂的不均匀沉积和锂枝晶的不可控生长总是导致锂利用率低、容量快速衰减和循环性能差。在此，我们设计了含有预组织三嗪环和羰基的亲锂共价有机框架（COF）作为锂金属电池（LMB）中的多功能中间层。富含孤对电子的三嗪环可作为吸引锂离子的供体，羰基作为有效配位锂离子的锂锚定位点。这些周期性排列的亚基显著引导均匀的锂离子通量分布，确保锂的平滑沉积并减少锂枝晶的形成。因此，具有COF中间层的对称电池在0.5和1.0 mA cm下表现出超过2450和1000 h的非凡循环稳定性，极化电压超低，约为12和14 mV。与硫（S）阴极和磷酸铁锂（LFP）阴极耦合，全电池也展示出卓越的能量密度和倍率性能。引入亲锂COF中间层后，Li-LFP电池在0.5 C下循环450次后表现出150 mAh g的高容量和86%的容量保持率。
