Designing Thin and Lightweight 3D Metallized Current Collectors With Functional Interfaces for High-Energy-Density Lithium-Sulfur Batteries

Lithium-sulfur batteries (LSBs) are highly advantageous for electric vehicles and portable electronics due to their high energy density. However, traditional metal foil current collectors pose many challenges in LSBs. On the anode side, the non-lithiophilic nature of copper foil leads to random lithium dendrite growth, increasing the risk of short circuits. On the cathode side, the electrochemical inertness and limited interfacial contact of aluminum foil cause slow polysulfide conversion under high sulfur loading, thus restricting cycling stability. Meanwhile, these heavy metal foils also reduce the overall energy density of the battery. Herein, we present an effective strategy to develop thin and lightweight 3D metallized current collectors (Ag@PEI-PP and Ni@PEI-PP) with functional interfaces for high-energy-density LSBs. These metallic collectors are made by cold-pressing polypropylene melt-blown fabrics and then applying metal coatings using a polymer-assisted deposition process. Compared to metal foil collectors, they possess an extremely light mass and excellent flexibility. The Ag@PEI-PP boosts the average Coulombic efficiency of lithium metal to 99.88% during cycling by enabling rapid lithium nucleation and uniform deposition. The Ni@PEI-PP maintains a high capacity retention rate of 99.88% per cycle over 200 cycles by speeding up the conversion of polysulfide and lithium sulfide. Based on the entire Li-S cell, including the current collector, active materials, and separator, the assembled LSB achieves high gravimetric (586 Wh kg⁻¹) and volumetric (472 Wh L⁻¹) energy densities. This metallic collector design provides an effective solution to improve the energy density and cycling stability of LSBs.