Sustainable hierarchical porous carbon from sugarcane bagasse for high-performance zinc-ion hybrid supercapacitors

The growing demand for sustainable and high-performance energy storage systems has driven interest in bio-derived carbon materials, particularly for use in zinc ion hybrid supercapacitors (ZIHSCs). In this study, sugarcane bagasse was utilized as a low-cost and renewable precursor for the synthesis of activated carbon, with its structure significantly enhanced through a templating method using magnesium oxide. The resulting modified sugarcane bagasse-derived activated carbon (SAC) exhibited a highly porous and more ordered carbon framework. These structural improvements enabled superior ionic diffusion and electrical conductivity, making the material highly effective as a ZIHSC cathode. The modified SAC-based ZIHSC system achieved an impressive specific capacitance of 482 F/g and a specific capacity of 268 mAh/g at a current density of 1 A/g. Moreover, it demonstrated excellent cycling stability with 80 % capacity retention over 1000 cycles and nearly ideal charge transfer and reversibility. Compared with previously reported ZIHSC technologies, this system offers a compelling alternative for next-generation energy storage solutions, highlighting the potential of agricultural waste valorization in sustainable device development.