Strategies to enhance the electrochemical performance of strontium-based electrode materials for battery-supercapacitor applications

Abstract

• Sonochemical approach was employed for synthesis of sulfides-based electrode materials. • The optimized electrodes show excellent specific capacity and rate capability. • Hybrid device (SrS//AC) was assembled revealing remarkable energy density (44.39 Whkg -1 ). • Capacitive and diffusive contribution was investigated through Dunn’s model. Asymmetric supercapacitors (SCs) have gained peculiar attention in energy storage domain. However, they still lack to accommodate high specific energy (E s ) and power density (P s ) demands. Therefore, the performance enhancement of supercapacitors by utilizing various electrode materials with superior electrochemical activities is desired. Herein, we have studied various strontium-based materials for asymmetric device applications. Initially, strontium oxide (SrO), phosphide (Sr 3 P 2 ), and sulfides (SrS) were sonochemically synthesized. The structural, morphological, and elemental study were performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). At first, three electrode system was used to execute electrochemical testing, which revealed SrS to hold prime performance compared to SrO and Sr 3 P 2 . The SrS sample obtained high specific capacity (Q s ) of 451.7 C/g (3 mV/s) and 202.5 C/g (0.5 A/g). The electrochemical analysis of the aforementioned SrS electrode was further investigated in two electrode configuration with activated carbon (AC). The device exhibited 44.39 Wh/kg E s and P s of 595 W/kg and attained power of 8400 W/kg while having E s of 12.9 Wh/kg with significant capacity retention of 89.6% over 5000 cycles. Furthermore, a simulation approach was scrutinized to verify the capacitive and diffusive contributions. The results obtained predicts strontium sulfides to be efficient materials for asymmetric supercapacitor applications.