Rational Design of Hierarchically Engineered Interfaces for High-Energy-Density and Long-Cycle-Life Anode-Free Lithium Metal Batteries

Anode-free lithium metal batteries (AFLBs) represent a transformative approach toward next-generation energy storage systems by eliminating the conventional lithium-containing anode, thereby maximizing gravimetric and volumetric energy densities. Despite their promise, practical deployment of AFLBs is impeded by critical challenges, including uncontrolled Li dendrite growth, severe volume fluctuations during plating/stripping, parasitic side reactions, and the formation of an unstable solid electrolyte interphase (SEI). These interrelated issues lead to low Coulombic efficiency, rapid capacity fade, and safety hazards, hindering long-term cyclability. This proposal aims to establish a unified materials design framework to simultaneously address these interfacial instabilities through hierarchical engineering of the anode-side interface. We propose a multi-scale strategy integrating three-dimensional (3D) lithiophilic current collectors, artificial protective interlayers with tailored ion transport channels, and synergistically optimized electrolytes to regulate Li nucleation, suppress dendritic growth, and stabilize the electrode/electrolyte interface. Specifically, we will design porous Cu architectures functionalized with lithiophilic metal alloys (e.g., Sn, Au) or carbon-based coatings to reduce local current density and promote uniform Li deposition. Concurrently, we will engineer ultrathin composite interphases incorporating inorganic LiF-rich domains and polymer matrices to enhance mechanical robustness and ionic conductivity. Coupled with localized high-concentration electrolytes or fluorinated solvents, this integrated interface design is expected to yield dense, dendrite-free Li plating with minimized side reactions. Advanced in situ/operando characterizations, including cryo-TEM and X-ray tomography, will be employed to elucidate dynamic Li deposition behaviors and SEI evolution. The proposed work will not only advance the fundamental understanding of interfacial regulation in anode-free systems but also provide scalable design principles for developing safe, high-energy, and durable AFLBs, paving the way for their commercialization in electric vehicles and portable electronics.