Nanoarchitectonics with yttrium role in controlled structural transformations and enhanced electrochemical performance of Y-BiVO4 nanorods for supercapacitor electrode applications

Structural transformations at the nanoscale, along with crystal imperfections introduced by ion doping, plays a critical role in improving electrochemical performance. In this study, a series of Y-doped BiVO₄ samples, with compositions Y_xBi_1-xVO₄ (x = 0, 0.01, 0.03, 0.05), were synthesized and studied for supercapacitor applications. The structural and morphological investigations verified that Y-ion incorporation significantly influences the transition, transforming spherical nanoparticles into rod-like nanostructure. This increases the electrochemical active surface area for higher redox activity. The electrochemical examinations confirmed notable improvements in specific capacitance, with the electrode containing 3 % Y doping achieving a maximum capacitance of 2127 F/g at a scan rate of 5 mV/s, along with excellent retention of 90.9 % after 6000 charge-discharge cycles. This remarkable performance is attributed to the enhanced charge transport and conductivity due to rod-like nanostructure. Power-law analysis (b = 0.68) and Dunn's method (54.93 % capacitive contribution at 100 mV/s scan rate) further substantiate the pseudocapacitive behavior of the material. The low R_s values from EIS and high specific capacitance of 3 % Y-BiVO₄ nanorods as promising candidates for high-performance supercapacitor applications, underscoring its potential to advance energy storage technology.