Radical Covalent Organic Frameworks Associated with Liquid Na‐K toward Dendrite‐Free Alkali Metal Anodes

Liquid sodium‐potassium (Na‐K) alloy has the characteristics of high abundance, low redox potential, high capacity, and no dendrites, which has become an ideal alternative material for potassium/sodium metal anodes. However, the high surface tension of liquid sodium potassium alloy at room temperature makes it inconvenient in practical use. Here, the Na‐K as reducing agent treats with hydrazone linkages of covalent organic frameworks (COFs) and obtain the carbon‐oxygen radical COFs (COR‐Tf‐DHzDM‐COFs). The preparation method solves the problems that the preparation process of the traditional Na‐K composite anode is complex and has high cost. The structures of the COR‐Tf‐DHzDM‐COFs are characterized by X‐ray diffraction （XRD), fourier transform infrared (FT‐IR), electron paramagnetic resonance (EPR), and solid‐state NMR measurements. It is the first time that carbon‐oxygen radical COFs from bulk COFs are constructed by one‐step method and the operation is flexible, convenient, and high rate of quality, which is suitable for big production and widely used. The cycle stability of the composite Na‐K anode is improved, which provides a new idea for the design of high‐performance liquid metal anode.