Three-Dimensional Printed Microarchitected Hierarchically Porous Biodegradable PLA/S/CNT Nanocomposite Electrodes for High-Performance Lithium–Sulfur Batteries

The commercialization of lithium–sulfur (Li–S) batteries requires high-sulfur-loading cathodes with robust electrochemical stability and practical areal capacities. Here, we report a scalable robocasting-based 3D-printing strategy to fabricate thick, self-standing sulfur/carbon nanotube (S/CNT) cathodes using a biodegradable polylactic acid (PLA) binder. This additive manufacturing approach enables precise control of sulfur loading and electrode architecture by simply adjusting the number of printed layers, achieving loadings up to 17 mg cm⁻². The engineered 3D porous framework facilitates efficient electron and Li⁺ transport across multiple length scales while mitigating polysulfide shuttling, thereby ensuring high sulfur utilization even at elevated electrode thicknesses (100–300 µm). The optimized cathodes deliver an initial capacity of 1096 mAh g⁻¹ at 6 mg cm⁻² with 96% capacity retention over 100 cycles at 0.5 C. At higher loadings of 11 and 17 mg cm⁻², the cells achieve remarkable areal capacities up to 9.2 mAh cm⁻² while maintaining 93%–95% capacity retention. By integrating sustainable materials with architected electrode design, this work establishes a viable pathway toward environmentally friendly, high-energy-density Li–S batteries with practical sulfur loadings and scalable manufacturing potential.