This research investigates the potential of salt gradient solar ponds (SGSPs) as a sustainable and effective solution for thermal energy storage. The study examines the design, construction, and performance of SGSP systems that incorporate coal cinder, comparing their performance with traditional SGSPs without coal cinder. A combination of experimental and numerical approaches is used to evaluate the thermal characteristics and energy efficiency of these systems. The findings indicate that the salt gradient solar pond with coal cinder (SGSP-CC) achieves notably higher temperatures across the Upper Convective Zone (UCZ), Non-Convective Zone (NCZ), and Lower Convective Zone (LCZ), with measured temperatures of 42.57°C, 56.8°C, and 69.86°C, respectively. These represent increases of 7.53%, 12.01%, and 15.49% over those in the conventional SGSP (SGSP-C). Additionally, the energy efficiency gains in the UCZ, NCZ, and LCZ for the SGSP-CC are noteworthy, with increases of 38.06%, 39.61%, and 42.73%, respectively, compared to the SGSP-C. The numerical simulations align closely with the experimental data, showing deviations of less than 5% in both temperature distribution and energy efficiency across all zones. This research highlights the potential of SGSPs with reflectors for improved thermal storage efficiency.