Molten Lean-Lithium Infiltrated Into a Lithiophilic 3D Carbon Framework for High-Performance Lithium-Sulfur Cells

The practical deployment of lithium-sulfur electrochemical cells is critically limited by the instability, dendrite growth, and excessive mass of conventional lithium-metal anodes, particularly under lean-lithium and lean-electrolyte conditions. In this research, a molten lean-lithium anode constructed on the first lithiophilic SiO₂-coated 3D conductive carbon framework is reported, which enables uniform lithium infiltration and stable long-term cycling. The 3D architecture ensures homogeneous current distribution and abundant nucleation sites, thereby lowering lithium nucleation overpotential, suppressing dendrite growth, and mitigating volume expansion. Electrochemical characterization confirms enhanced redox kinetics, reduced polarization, and improved Coulombic efficiency. When coupled with a high-loading polysulfide cathode (4 mg cm^-2) and operated under a low electrolyte-to-sulfur ratio (10 µL mg^-1), the lithium-sulfur full cell achieves a high initial capacity of 909 mAh g^-1, attains optimized low effective capacity of the anode to the cathode (N/P) ratio of 4.5, and maintains 500 mAh g^-1 after 200 cycles at a C/10 rate. Even at high rates up to 1C, the cell delivers stable performance with minimal voltage hysteresis and no dendritic failure. As a result, this scalable and cost-effective molten lithium strategy addresses critical challenges of lithium-metal anodes, offering a practical pathway toward high-energy-density lithium-sulfur batteries.