Green treatment of waste Crops: Porous and natural channel corn stalk electrode modified by orange peel for high-performance vanadium redox flow batteries

Electrodes in vanadium redox flow batteries (VRFBs) are inextricably linked to the versatility of VRFBs. Subsequent research revealed that batteries using bio-based modified carbon-felt (CF) exhibit extreme polarization. The research process ignored the polluting of the production process of the CF. In this study, the corn stalks were pre-treated with ligninase and hemicellulase to obtain channel corn stalks (CCS) with a low polarization effect. Orange peels were then used as the carbon source, sugar was used to activate the slurry, in which the CCS was modified by orange peel electrode (CCS500-14). It was shown in several ways that CCS500-14 enhances the diffusion effect on VO2+ ions with coefficients consistently in the range of 10−12-10−10cm2s−1. CCS500-14 has a specific capacitance of 413 F/g at 1 A/g, and after the current density is expanded by 30 times achieves 285 F/g, 69 % of the original. The VRFB cell with CCS500-14 achieve energy efficiency of 87.64 % in 500 cycles at 100 mA cm−2, significantly higher than the CF-based VRFB cell (79 %). This study demonstrates that the use of orange peel carbon-modified corn stalk electrode is practicable in the application of advanced VRFB energy storage systems, providing a new idea for replacing the CF electrode.