Tailoring Bismuth Antimonate nanocomposites with barium and calcium for superior electrochemical properties in supercapacitors

Abstract

This study employs a dual substitution strategy on Bismuth Antimonate to improve its performance as an electrode material for supercapacitors. Nanocomposites were synthesized by incorporating Barium (Ba²⁺) and Calcium (Ca²⁺) into Bismuth Antimonate in three different ratios, labeled as B₁C₁BiSO, B₁C₂BiSO, and B₂C₁BiSO. The simple solid-state method used for the preparation yielded nanocomposites with closely packed spherical nanostructures, resulting in a porous architecture that facilitates electrolyte access to the active surface areas. The incorporation of Ba²⁺ and Ca²⁺ creates additional active sites, significantly boosting the electrochemical results of BiSO. Notably, the B₁C₂BiSO electrode achieves a capacitance of 573 F/g at 1 A/g in a three-electrode setup, retaining 88 % of its original capacitance after 5000 cycles—surpassing the performance of other samples. Additionally, we developed an asymmetric supercapacitor device (B₁C₂BiSO||AC) with activated carbon for the negative electrode. This device delivers a capacitance of 117.5 F/g at 1 A/g and maintains 76.25 % capacity retention over 15,000 cycles. This strategy proves to be a capable approach to advance the energy storage capabilities of asymmetric supercapacitor devices.