NiCo2S4 Nanoparticles Decorated Carbon-Rich Carbon Nitride Nanosheets for Indoor Light-Active Photo-Rechargeable Hybrid Zinc-Ion Battery

Abstract Photorechargeable storage devices are an emerging field for storing solar energy as a charge. In this work, a hybrid hierarchical nanomaterial made of carbon-rich carbon nitride nanosheets (CCN) and NiCo2S4 nanodots (NCS) is prepared for a photoactive electrode. Optoelectronic studies suggest that the prepared CCN has excellent surface properties, broad visible-light absorbance, and good conductivity, whereas NCS has a higher density of redox-active sites, thereby improving light-induced storage performance. A suitable bandgap with aligned band positions between the counterparts enables efficient charge separation in the pristine materials. The fabricated NCS@CCN-based photoelectrode is evaluated for a photorechargeable hybrid zinc-ion battery in 3 E and 2 E configurations. The electrode shows a maximum specific capacity of 15.56 and 19.44 mAh g−1 under dark and light conditions, respectively (scan rate of 25 mV s−1), and a maximum 93.34% photoinduced capacity increment is observed at 200 mV s−1. Furthermore, the photo-assisted storage performance of the fabricated device is demonstrated using an indoor light source. The photo-induced enhancement in specific capacitance (%) ranges from 64.46% to 83.92%. Even after 500 cycles of CV and GCD, the device shows a retention capacitance of 73%. Furthermore, the possible energy storage mechanisms on the photocathode are investigated in detail.