3D-Printed Nitrogen-Doped Carbon Interlayers for Spatially Modulating Lithium-Sulfur Reactions

The practical commercialization of lithium-sulfur (Li-S) batteries mainly confronts two fundamental obstacles associated with sulfur cathode: sluggish sulfur redox conversion kinetics and the detrimental polysulfide shuttling phenomenon. As an "external" optimization strategy, the functional interlayers demonstrate considerable promise for enhancing battery performance through sophisticated spatial-chemical multidimensional working mechanisms. Herein, a nitrogen-doped 3D carbon (3D-NC) functional interlayer is designed and fabricated by using direct ink writing (DIW) 3D printing technology. The precisely engineered 3D architecture provides abundant sulfur with active sites and establishes continuous 3D electron-conductive networks, effectively mitigating polysulfide migration while simultaneously optimizing sulfur conversion reaction kinetics. The resulting Li-S battery with a sulfur mass loading of 3.0 mg cm^-2 delivers a specific exceptional capacity of 955.4 mA h g^-1 at 0.2 C with outstanding capacity retention of 90.2% per cycle over 100 cycles. Furthermore, under the high sulfur mass loading of 8.3 mg cm^-2 and lean electrolyte dosage of 5.0 µL mg^-1, the Li-S battery still achieves a remarkable areal capacity of 6.0 mA h cm^-2 and favorable lifespan.