Large amplification of triboelectric property by allicin to develop high performance cellulosic triboelectric nanogenerator

Recently, cellulose has grabbed a tremendous attention in the fabrication of triboelectric nanogenerators (TENGs) because of their biodegradability and renewability. However, the weak surface polarity and inadequate surface functional groups severely limit its advancement towards high performance TENGs. This study unveils for the first time the majestic power of allicin extracted from garlic juice, in amplifying the triboelectric property of cellulose nanofibers (CNFs), aiming to develop a renewable high-performance cellulosic triboelectric nanogenerators (TENGs). Allicin was grafted onto CNF using a ‘thiol-ene’ click chemistry. It has been observed that after allicin modification, the CNF film became mechanically and thermally robust. The peak output voltage and current reached to 7.9 V and 5.13 μA, when modified film was used in a TENG, which was ~6.5 times greater than the pristine cellulose based TENG (1.23 V, 0.80 μA). Because of higher surface polarity, electron donating capacity and surface roughness of the modified film, the current density and power density increased from 0.2 to 1.28 µA/cm² and 0.25 to 10.13 µW/cm² i.e 6 and 41 times greater respectively, than the pristine cellulose TENG. Such large electrical enhancements surpasseed many recent reports on cellulose TENG. Furthermore, the allicin grafted TENG showed outstanding stability against humidity, long term cyclic load and environmental aging. These findings clearly demonstrated that tailoring the triboelectric performance by garlic juice could be a major breakthrough in the hunt for durable, high performance self-powered biodegradable TENGs.