Evaluation of d-block metal sulfides as electrode materials for battery-supercapacitor energy storage devices

Abstract

Transition metal sulfides are among the most favored materials for energy storage applications. In this work, an innovative approach to synthesize three distinct samples of manganese sulfide was realized. The three samples were synthesized via sonochemical, hydrothermal and electrodeposition techniques, respectively. At first the elemental and morphological results were obtained for the samples. To evaluate the energy storage capabilities, electrochemical testing was accomplished, employing galvanostatic charging/discharging, cyclic voltammetry, and electro-impedance spectroscopy. A battery-supercapacitor device was assembled by the amalgamation of the superior performing sample with activated carbon in a single device. The device displayed a 127.5 Wh kg−1 energy density and 2550 W kg−1 power density at 3 A g−1, respectively, with a retained capacity of 89.12 % after 1000 cycles. In addition to the electrochemical results, a simulation approach was introduced to extract the capacitive and diffusive contribution of the fabricated device through Dunn's model. The showcased device performance supports the conception of electro-synthesizing materials for energy storage applications.