Three-dimensional (3D) porous frameworks have attracted considerable interest as lithium-metal electrodes for nextgeneration rechargeable batteries. The high surface areas and large pore volumes of 3D frameworks are beneficial for reducing local current densities and suppressing volume changes. However, uneven Li plating on top of the framework electrode (top growth) has yet to be resolved. To enable the bottom-up Li growth while suppressing the top growth, herein, we propose a rational design of 3D framework electrodes with an interfacial activity gradient (IAG) based on a kinetics-based mechanistic analysis. A simulation demonstrates that an IAG design promotes the bottom-up Li growth, which is experimentally proven using model architectures. The IAG-Cu framework shows considerable improvements in morphological stability and reversibility during high-capacity Li storage, compared to the Cu framework with a uniform interfacial activity. This work provides fundamental insight into the design of 3D frameworks to boost the cycling stability of Li-metal batteries.

Lithium (Li) metal is regarded as the most attractive anode material for high-energy Li batteries, but it faces unavoidable challenges-uncontrollable dendritic growth of Li and severe volume changes during Li plating and stripping. Herein, a porous carbon framework (PCF) derived from a metal-organic framework (MOF) is proposed as a dual-phase Li storage material that enables efficient and reversible Li storage via lithiation and metallization processes. Li is electrochemically stored in the PCF upon charging to 0 V versus Li/Li + (lithiation), making the PCF surface more lithiophilic, and then the formation of metallic Li phase can be induced spontaneously in the internal nanopores during further charging below 0 V versus Li/Li + (metallization). Based on thermodynamic calculations and experimental studies, it is shown that atomically dispersed zinc plays an important role in facilitating Li plating and that the reversibility of Li storage is significantly improved by controlled nanostructural engineering of 3D porous nanoarchitectures to promote the uniform formation of Li. Moreover, the MOF-derived PCF does not suffer from macroscopic volume changes during cycling. This work demonstrates that the nanostructural engineering of porous carbon structures combined with lithiophilic element coordination would be an effective approach for realizing high-capacity, reversible Li-metal anodes.

The synergistic surface tailoring of three-dimensional Cu frameworks achieved via Ag-induced activation and Al2O3-induced passivation leads to a significant improvement in the Li plating–stripping efficiency and cycling performance.