Lu Chengyi, Chao Ming, Wu Yuchen, Lu Jiahao, Liu Yihao, Liu Wenchao, Chen Hong, Xie Haijiao, Zhang Jing, Rummeli Mark H, Yang Ruizhi
College of Energy, Soochow Institute for Energy and Materials Innovations, Soochow University, Suzhou 215006 China.
Beijing Synchrotron Radiation Facility, Institute of High Energy Physics Chinese Academy of Sciences, Beijing 100049 China.
J Colloid Interface Sci. 2025 May;685:255-266. doi: 10.1016/j.jcis.2025.01.135. Epub 2025 Jan 17.
Lithium (Li) metal anodes hold great promise for next-generation secondary batteries with high energy density. Unfortunately, several problems such as Li dendrite growth, low Coulombic efficiency and poor cycle life hinder the commercialization of Li metal anodes. Herein, we design a highly lithiophilic carbon cloth host modified with Sn-doped zinc oxide (ZnO) (ZnSn-CC) directly derived from a bimetallic ZnSn metal-organic framework (ZnSn-MOF), which boosts uniform Li plating/stripping during charge-discharge and effectively protects the Li metal anode. Due to the lithiophilic modification, the cycling reversibility of the host material is increased and the growth of Li dendrites and the generation of "dead Li" are inhibited. As a result, the resultant composite Li metal anode (ZnSn-CC@Li) manages to retain cycling stability for over 1000 h at a current density of 1 mA cm and a specific capacity of 1 mAh cm in a symmetric cell. When paired with the LiFePO (LFP) and LiNiCoMnO (NCM) cathodes, both the assembled ZnSn-CC@Li||LFP and ZnSn-CC@Li||NCM full cell achieve good rate capability and improved cycle life. Density functional theory calculations, in combination with in-situ X-ray diffraction (XRD), in-situ time-lapse optical testing, ex-situ extended X-ray fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) analysis, reveal the origin of the synergetic interaction between Tin (Sn) and Zinc (Zn) atoms upon Sn-doping in ZnO. The improved lithiophilicity can be attributed to the incorporation of Sn atoms, which have a higher coordination number than Zn atoms, into the ZnO lattice, forming joint adsorption sites of multiple oxygen atoms toward Li atoms. The Li nucleation barrier is thereby reduced and the smooth Li deposition is facilitated. The findings provide a new strategy for the rational design of functional host materials based on bimetallic MOFs derivatives toward high-performance and safe Li metal batteries.
锂（Li）金属阳极对于具有高能量密度的下一代二次电池具有巨大潜力。不幸的是，诸如锂枝晶生长、低库仑效率和较差的循环寿命等几个问题阻碍了锂金属阳极的商业化。在此，我们设计了一种用锡掺杂的氧化锌（ZnO）（ZnSn-CC）改性的高度亲锂碳布主体，其直接源自双金属ZnSn金属有机框架（ZnSn-MOF），这促进了充放电过程中锂的均匀沉积/剥离，并有效保护锂金属阳极。由于亲锂改性，主体材料的循环可逆性提高，锂枝晶的生长和“死锂”的产生受到抑制。结果，所得复合锂金属阳极（ZnSn-CC@Li）在对称电池中在1 mA cm的电流密度和1 mAh cm的比容量下能够保持超过1000小时的循环稳定性。当与磷酸铁锂（LFP）和镍钴锰酸锂（NCM）阴极配对时，组装的ZnSn-CC@Li||LFP和ZnSn-CC@Li||NCM全电池均实现了良好的倍率性能和改善的循环寿命。密度泛函理论计算与原位X射线衍射（XRD）、原位延时光学测试、非原位扩展X射线精细结构（EXAFS）和X射线吸收近边结构（XANES）分析相结合，揭示了在ZnO中掺杂锡时锡（Sn）和锌（Zn）原子之间协同相互作用的起源。亲锂性的提高可归因于具有比Zn原子更高配位数的Sn原子掺入ZnO晶格中，形成多个氧原子对Li原子的联合吸附位点。从而降低了锂成核势垒并促进了锂的平滑沉积。这些发现为基于双金属MOF衍生物合理设计用于高性能和安全锂金属电池的功能性主体材料提供了一种新策略。
