Supercapacitive Properties of Tuberose‐Structured Sr _(1−x) Bi _x ( <scp>OH</scp> ) ₂ Thin Films Grown via <scp>SILAR</scp> Method

ABSTRACT This study presents a simple method for synthesizing tuberose‐structured Sr (1−x) Bi x (OH) 2 thin films (x = 0, 0.02, 0.05, and 0.07) on stainless steel (SS) utilizing the successive ionic layer adsorption and reaction (SILAR) for supercapacitive electrodes. The Bi incorporation modulated the crystallinity and surface microstructure of Sr(OH) 2 , thereby enhancing the active surface area and redox activity. In particular, the x = 0.07 sample exhibited a smaller size structure that enabled efficient ion transport and electrolyte diffusion, delivering a specific capacity of 330 C g −1 at 1.5 mA, along with an energy density of 7.75 Wh kg −1 , and a power density of 4176 W kg −1 in a 1 M Na 2 SO 4 electrolyte, as illustrated by the Ragone plot while retaining ~60% of its capacity after 2500 charge–discharge cycles. The enhanced electrochemical behavior is mostly due to synergistic effects of Bi doping, which improve electrical conductivity and redox activity. Overall, these findings point to Sr (1−x) Bi x (OH) 2 as a viable, inexpensive and eco‐friendly electrode material for pseudocapacitor applications.