Urea-Linked Covalent Organic Framework as a Li-Ion Guided Channel Enabling Ultra-Stable Lithium Metal Anode in Carbonate-Based Electrolyte.

Lithium (Li) metal exhibits great potential for achieving high-energy-density rechargeable batteries. However, the practical application of Li metal anodes is severely hindered by the uncontrollable growth of lithium dendrites as well as the instability of the spontaneously generated solid electrolyte interphase (SEI), causing safety concerns and lifespan issues. Herein, we customize a novel urea-linked covalent organic framework (COF-531) as an interfacial Li-ion guided channel. The COF-531 is constructed utilizing a highly dynamic urea-linkage, which balances the low reactivity of N-rich melamine (MA), and could simultaneously provide abundant lithiophilic N sites and crystallinity ordered ion channels. This structure is able to promote efficient Li de-solvation and transport, leading to uniform deposition via inhibiting dendrites growth. As a result, the COF@Li anode exhibits remarkable cycling performance under high current density (10 mA cm over 11500 h and 20 mA cm over 6000 h in the symmetric Li cells, and 1013 mAh g after 500 cycles under 8.4 A g in a COF@Li || S-in-CMK-3 cell), setting a new benchmark for long-cycle performance in carbonate-based electrolyte. Remarkably, the COF-531 can be produced at a low-cost (∼58.6 USD kg) on a kilogram scale. This work addresses a critical bottleneck in the commercialization of Li-metal batteries.