Manipulating metal growth in hollow ionic-electronic conductor for anode-free lithium metal batteries

Anode-free lithium metal batteries (AFLMBs) demonstrate promising high energy density yet suffer from irregular Li deposition, parasitic reactions, and severe volume expansion. The current anode modulation strategies such as tailored solid electrolyte interphase (SEI) and lithiophilic host architectures can hardly simultaneously resolve all above issues, especially at high-capacity Li deposition. Here, we design a Li-rich, hollow ionic-electronic conductor (HIEC) interlayer, which integrates metallic Li encapsulation and interfacial protection, thus guiding highly reversible thick Li deposition (5 milliampere-hours per square centimeter). In addition, the built-in electron-deficient domains in the HIEC facilitate the formation of the hierarchical SEI and further mitigate active Li corrosion. These synergistic effects of the interlayer enable stable cycling in batteries under both anode-less and anode-free configurations, attaining >99% coulombic efficiency under industrial-level cathode loading and lean electrolyte conditions. This study highlights the significance of interlayers in integrating the SEI and host functions and provides a viable and scalable solution for energy-dense batteries.