Structural and electrochemical investigation of benzimidazole picolinic acid derivatives for sustainable energy storage applications.

Supercapacitors are widely employed in electric vehicles and portable electronics due to their rapid charge-discharge capability, high power density, and energy efficiency; however, many still depend on non-renewable materials. This study reports the synthesis and comprehensive characterization of benzimidazole picolinic acid (BPEP) as a sustainable, high-performance electrode material for supercapacitors. Optical and electrical analyses reveal significant π → π* and n → π* transitions, with prominent UV-visible absorption peaks at 282 nm (experimental) and 294 nm (theoretical). BPEP exhibits excellent light absorption, achieving 99% light-harvesting efficiency at 300 nm and an extinction coefficient of 2250, underscoring its strong optical potential. Frontier Molecular Orbital (FMO) analysis indicates a band gap of 3.9 eV, reflecting notable chemical hardness and thermal stability. Additionally, the negative chemical potential (μ = -4.377 eV) and high electrophilicity index (ω = 5.249 eV) suggest enhanced chemical reactivity and stability that key attributes for energy storage. Electrochemical impedance analysis reveals a maximum specific capacitance of 125.45 F/g at a scan rate of 10 mV/s, confirming efficient charge storage behavior. Vibrational analysis and optimized geometry further affirm the structural integrity of BPEP. Collectively, these results highlight the optical, topological, and electrochemical merits of BPEP, establishing it as a promising eco-friendly candidate for next-generation supercapacitor electrodes.