Lithium metal batteries (LMBs) represent the favorable option for the new-generation high-energy-density batteries. Nevertheless, LMBs utilizing the merchant separators consistently encounter some issues including the irregular development of lithium dendrites, bulk fluctuation of lithium anode, and excessive electrolyte consumption. In this study, we innovatively coat the double-side of commercial polypropylene (PP) separator with an electrostatically assembled composite of CoMo-layered double hydroxide (CoMo-LDH) hollow polyhedra and high crystallinity graphitic carbon nitride to enhance the electrochemical properties of separator. The CoMo-LDH has a certain effect on accommodating the bulk variation throughout Li deposition/stripping procedure. Additionally, the triazine-based structure of graphitic carbon nitride synthesized by the molten salt assisted approach introduces Cl– to regulate the ion selectivity in separator and promotes the uniform plating of Li+. Satisfactorily, it is demonstrated that the double-modified PP (DMP) separator exhibits a significantly improved ionic conductivity (1.11 mS cm–1) and Li+ transference number (0.75) compared to conventional PP separator. In-situ puncture experiment of lithium dendrites reveals that the DMP separator withstands a lithium deposition capacity of 17 mAh cm–2. Furthermore, the DMP-equipped Li//LFP full-cell delivers a primary discharge capacity of 149 mAh g–1 and maintains 96.6% for the capacity retaining rate after 100 cycles at 0.2 C. Fortunately, after 500 cycles at 1 C, a retention rate of 94.1% is still achieved. Meantime, Li//NCM523 full-cell assembled with DMP separator exhibits a good electrochemical performance at 0.2 C. This work exhibits the universality and practicality of DMP separator as well as offers a dependable solution for restraining the development of lithium dendrites for LMBs. Furthermore, this solution would also be used to other alkali metal anodes.

中文翻译：

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巧妙的双改良策略制备锂金属电池“六边形战士”隔膜


锂金属电池 （LMB） 是新一代高能量密度电池的有利选择。然而，使用商用隔膜的 LMB 一直遇到一些问题，包括锂枝晶的不规则发展、锂负极的体积波动和电解液消耗过多。在这项研究中，我们创新性地用 CoMo 层状双氢氧化物 （CoMo-LDH） 空心多面体和高结晶度石墨氮化碳的静电组装复合材料涂覆商用聚丙烯 （PP） 隔膜的双面，以增强隔膜的电化学性能。CoMo-LDH 对适应整个 Li 沉积/剥离过程中的本体变化具有一定的影响。此外，通过熔盐辅助方法合成的石墨氮化碳的三嗪基结构引入了 Cl– 以调节隔膜中的离子选择性，并促进 Li+ 的均匀电镀。令人满意的是，与传统的 PP 隔膜相比，双重改性的 PP （DMP） 隔膜表现出显着改善的离子电导率 （1.11 mS cm–1） 和 Li+ 迁移数 （0.75）。锂枝晶的原位穿刺实验表明，DMP 隔膜可承受 17 mAh cm–2 的锂沉积容量。此外，配备 DMP 的 Li//LFP 全电池提供 149 mAh g–1 的一次放电容量，并在 0.2 C 下循环 100 次后保持 96.6% 的容量保持率。幸运的是，在 1 C 下循环 500 次后，仍实现了 94.1% 的保留率。同时，与 DMP 隔膜组装的 Li//NCM523 全电池在 0.2 C 下表现出良好的电化学性能。 这项工作展示了 DMP 隔膜的通用性和实用性，并为抑制 LMB 锂枝晶的发展提供了可靠的解决方案。此外，该溶液还将用于其他碱金属阳极。