Preparation of N-doped porous biocarbon with high surface area via controlled-burning for Zn-ion hybrid supercapacitor applications

Abstract

A novel strategy has been developed for synthesizing high-surface area nitrogen-doped biocarbon derived from rotten wood, tailored for efficient zinc-ion hybrid supercapacitor applications. By employing a Borax-K₂CO₃ system that enables controlled combustion in an air environment, the intrinsic interconnected channels and pores of natural wood are effectively preserved and further enhanced. This molten salt system not only prevents the collapse of the inherent porous structure but also promotes additional pore formation through activation. Consequently, a porous biocarbon with a hierarchical structure is produced, achieving an impressive specific surface area of 2196 m²·g⁻¹ . The optimized biocarbon material (RW-15) was integrated into a zinc-ion hybrid supercapacitor, delivering a notable capacitance of 175 F·g⁻¹ at 0.5 A·g⁻¹ . Additionally, the device retained 97 % of its initial capacitance over 10,000 cycles and achieved a notable energy density of 79 Wh·kg⁻¹ within a wide operating voltage window of 1.8 V. This work presents a sustainable, cost-effective, and scalable method for producing advanced porous carbon materials, offering strong potential for next-generation energy storage technologies.