Upcycled waste-to-carbon nanosphere/MoS2 hybrid electrodes coupled with sodium alginate gel electrolytes for advanced energy storage

In this study, sodium alginate (SA)-based lyotropic liquid crystal (LLC) gel electrolyte was designed and integrated with laser-derived carbon nanosphere (CNS)/molybdenum disulfide (MoS 2 ) hybrid electrodes to achieve enhanced electrochemical performance in supercapacitors. The SA-LLC gel electrolyte was optimized at different concentrations, and the formation of ordered micellar domains and their thermal stability were confirmed through polarized optical microscopy (POM) and dynamic light scattering (DLS). The unique self-assembled structure of the LLC gel facilitated efficient ion conduction and stable electrode-electrolyte interfaces. Complementarily, the CNS, derived from onion peel via laser-induced carbonization, provided high conductivity and porosity, hydrothermally synthesized MoS 2 exhibited distinctive nanosheet-like nanoflakes offering abundant redox-active sites. The optimized device, employing a 1:2 CNS/MoS 2 ratio and 25% SA-LLC gel electrolyte, achieved a specific capacitance of 548.7 F / g at 1 A / g , a maximum energy density of 15.2 Wh k g ⁻ 1 , and a power density of 33 kW k g ⁻ 1 , while maintaining a Coulombic efficiency of 85.4% after 5000 cycles. This study highlights the pivotal role of the SA-LLC gel electrolyte in enabling efficient ion transport and mechanical flexibility, offering a green and versatile platform for next-generation high-performance supercapacitors. • The SA-based LLC gel electrolyte was developed, characterized by ordered micellar structures and robust thermal stability, as confirmed by POM and DLS analyses. • The CNS/MoS₂ hybrid electrodes integrate conductive porous carbon nanospheres with Mo S 2 nanoflakes exhibiting nanosheet-like growth, which is abundant in redox-active sites. • The optimal electrode ratio of 1:2 CNS/MoS₂, combined with a 25% SA-LLC gel, yielded superior ion transport and interface stability. • The device demonstrated high performance, achieving 548.7 F/g at 1 A/g, an energy density of 15.2 Wh/kg, a power density of 33 kW/kg, and an efficiency of 85.4% after 5000 cycles. • This system presents a sustainable, flexible, and efficient platform for next-generation supercapacitors utilizing environmentally friendly materials.