Piezoceramics are extensively utilized in electronic devices such as sensors, actuators, and capacitors. Nevertheless, most piezoceramic devices used in commercial applications are constructed from Pb-based materials, which pose toxicity and threaten human health. Some studies focused on lead-free piezoceramics, including BNT, KNN, BT, BF, ST, and their solid solutions. The BNT-ST ceramics exhibit the most favorable qualities in terms of strain generated by an electric field, even when the electric field applied is minimal. Thus, our study discovers a novel piezoceramic system called Pb-free Al2O3-modified BNT-ST. The samples are synthesized using a traditional solid-phase reaction technique. The specimens are subjected to sintering at a temperature of 1150 ℃ for 2 h under atmospheric conditions. The study examines the impact of Al2O3 on the crystal structure and polarization-electric field loops of BNT-ST piezoelectric ceramics. The pure BNT-ST sample shows a tetragonal structure and the addition of Al2O3 only increases their tetragonality. More notably, pure BNT-ST ceramic shows a small energy storage density of 0.088 J/cm3 and a low energy storage efficiency of 10%. The addition of Al2O3 increases the energy capabilities of the BNT-ST sample. The BNT-ST:0.03Al2O3 sample shows the largest energy storage density of 0.319 J/cm3 and an energy storage efficiency of 46%. The results confirm the potential of Al2O3 dopant in the energy enhancement of Bi-based piezoceramics.