Exploring unique properties of polypyrrole reinforced molybdenum disulfide electrodes for aqueous aluminum ion capacitors

Abstract

Polypyrrol (PPy) as a highly conductive polymer displays remarkable pseudocapacitive properties. This paper focuses on the electrodeposition of PPy on conductive carbon cloth (CC) as a substrate with MoS₂ nanosheets as an intermediate layer. The electrodeposition of PPy was carried out at a constant pressure for 150 s, 300 s, 450 s, and 600 s at 0.75 V and compared with pristine substrate. Then the PPy@MoS₂/CC electrode was electrochemically tested in 1 M AlCl₃ electrolyte exhibiting capacitance of 659 F g⁻¹, 815 F g⁻¹, 464 F g⁻¹, and 363 F g⁻¹, respectively, compared to 595 F g⁻¹ for pristine substrate. Many different types of tests have demonstrated that the successfully deposited PPy@MoS₂ material displays a wrinkled structure. Further, using electrochemical methods and additional techniques, the impact of cation size on the performance of electrodes was analyzed using 1 M AlCl₃, 1 M MgCl₂, 1 M KCl, and 1 M NaCl electrolytes. The specific capacitance of PPy@MoS₂/CC electrode (PPy deposited for 300 s) was found to be 815 F g⁻¹ in 1 M AlCl₃, 758 F g⁻¹ in 1 M KCl, 649 F g⁻¹ in 1 M NaCl, and 670 F g⁻¹ in 1 M MgCl₂ electrolytes at 2 A g⁻¹. Finally, the symmetric device PPy@MoS₂/CC//PPy@MoS₂/CC displays a maximum energy density of 26.39 Wh Kg⁻¹ at 500 W Kg⁻¹ and a long lifespan of 10,000 cycles.