Recycling waste plastics into hydrogen and carbon nanotube composites toward sustainable energy generation and storage

Abstract In this study, post-consumer low-density polyethylene packaging waste was converted via plasma-assisted and conventional thermal pyrolysis, respectively. A perovskite-type La0.6Ca0.4Co0.2Fe0.8O3−δ pre-catalyst was employed to simultaneously generate hydrogen and carbon nanomaterials. The plasma-thermal catalytic process demonstrated superior conversion efficiency for both gaseous and solid products compared to the two-stage thermal catalytic approach. To evaluate the potential of the synthesized carbon nanotube composites for low-grade energy storage applications, the metal oxide–carbon composites obtained from both synthesis methods were employed as a host for sulfur cathodes in lithium–sulfur batteries. Electrochemical analysis demonstrated comparable cycling stability between the two approaches, with initial discharge capacities of 296 and 291 mAh g−¹, which stabilized at 125 and 112 mAh g−¹ after 50 cycles at a 0.05 C (1C = 1675 mAh g−¹) rate for the plasma-thermal and thermal catalytic processes, respectively. These results highlight the feasibility of directly incorporating the derived carbon nanotube composites into energy storage technologies, offering a potentially sustainable route for large-scale plastic waste valorization and advanced material development.