Sb₂S₃ Nanorods for Photoenhanced Li-Ion Batteries: A Synergetic Balance Between Energy Harvesting and Storage

Photobattery technology using a single active material for simultaneous solar energy harvesting and storage presents a significant leap in solar energy storage for low-power IoT (Internet of Things) applications. However, most of the photobatteries rely either on conventional photovoltaic or battery material to achieve bifunctionality, leading to mismatch between solar absorption and electrochemical stability, thus ultimately compromising overall device performance. This study demonstrates the use of low-cost sol-gel synthesized antimony sulphide (Sb₂S₃) nanorods (NRs) as the active material for stable two-electrode Lithium-ion photobattery, which shows excellent optical (E_g≈1.80 eV, direct), optoelectronic (photocurrent ≈4 µA cm⁻²) and electrochemical attributes (specific capacity ≈715 mAh g⁻¹, 200 mA g⁻¹). Photoelectrochemical measurements show enhanced kinetics with increase in sites for Li-ions under illumination, resulting in 40.16% enhancement in specific capacity at 1000 mA g⁻¹. Additionally, a galvanostatic photoconversion and storage efficiency of ≈24.53% at 2200 mA g⁻¹ is recorded under white LED illumination (12 mW cm⁻²). The demonstrated photobattery successfully powered a commercial thermo-hygrometer continuously for 7 days. These attributes highlight the potential of Sb₂S_3-based photobatteries to drive low-power off-grid IoT devices and offer advanced energy solutions aligned with a sustainable future.