Hydrogen-Bonded Organic Framework as Superior Separator with High Lithium Affinity C═N Bond for Low N/P Ratio Lithium Metal Batteries

Lithium dendrite and side reactions are two major challenges for lithium metal anode. Here, the highly lithophilic triazine ring in the hydrogen-bonded organic framework is recommended to accelerate the desolvation process of lithium ions. Among them, the formation of Li-N bonds between lithium ions and the triazine ring in CAM reduces the diffusion energy barrier of Li+ crossing the SEI interface and the desolvation energy barrier of Li+ exiting from the solvent sheath so that the rapid and homogeneous deposition of lithium-ion can be achieved. Meanwhile, the lithium-ion migration coefficient can be as high as 0.70. CAM separator is used to assemble lithium metal batteries with nickel-rich cathodes (NCM 622). When N/P = 8 and 5, the capacity retention rates of Li-NCM 622 full cell are 78.2% and 80.5% after 200 and 110 cycles, respectively, and the Coulomb efficiency can be maintained at 99.5%, showing excellent cycle stability.