Ultra-efficient and stable Janus interface to construct high-performance sulfide-based all-solid-state lithium metal batteries

All-solid-state lithium metal batteries (ASSLMBs) are expected to replace traditional lithium-ion batteries due to their excellent safety and high energy density. However, the poor interfacial stability between lithium metal and solid electrolyte is a major obstacle. Here, we design a stable interface with “dredging+blocking” dual protection. The interface is composed of a composite lithium anode and a functionalized electrolyte. During lithium-ion plating/stripping, the composite lithium anode of the hybrid SEI interface has a good electron/ion conductive network to ensure the rapid transmission of electrons in the lithium anode, enhance the bulk diffusion of lithium, and play a role in “dredging” the distribution of lithium ions. When lithium dendrites further grow along the interparticle space of the electrolyte, especially at high current density, the functional electrolyte can be used as a second protective line. By reacting with lithium metal, consuming lithium, and further forming a stable interface, it plays a role in “blocking” lithium dendrite growth. Therefore, the symmetrical battery achieves a stable cycle (1400 h, 0.5 mA cm⁻²) and an ultra-high critical current density (5.2 mA cm⁻²). ASSLMBs achieve long-cycle performance (700 cycles, 70 % capacity retention) and good rate performance in a wide temperature range. This dual modification strategy significantly enhances lithium metal compatibility, offering a viable path for the development of high-performance ASSLMBs.