Comparative Study of the Supercapacitive Performance of Three Ferrocene-Based Structures: Targeted Design of a Conductive Ferrocene-Functionalized Coordination Polymer as a Supercapacitor Electrode.

As redox-active based supercapacitors are known as highly desirable next-generation supercapacitor electrodes, the targeted design of two ferrocene-functionalized (Fc(COOH) ₂ ) clusters based on coinage metals, [(PPh ₃ ) ₂ AgO ₂ CFcCO ₂ Ag(PPh ₃ ) ₂ ] ₂ ⋅7 CH ₃ OH (SC ₁ : super capacitor) and [(PPh ₃ ) ₃ CuO ₂ CFcCO ₂ Cu(PPh ₃ ) ₃ ]⋅3 CH ₃ OH (SC ₂ ), is reported. Both structures are fully characterized by various techniques. The structures are utilized as energy storage electrode materials, giving 130 F g ^-1 and 210 F g ^-1 specific capacitance at 1.5 A g ^-1 in Na ₂ SO ₄ electrolyte, respectively. The obtained results show that the presence of Cu ^I instead of Ag ^I improves the supercapacitive performance of the cluster. Further, to improve the conductivity, the PSC ₂ ([(PPh ₃ ) ₂ CuO ₂ CFcCO ₂ ] _∞ ), a polymeric structure of SC ₂ , was synthesized and used as an energy storage electrode. PSC ₂ displays high conductivity and gives 455 F g ^-1 capacitance at 3 A g ^-1 . The PSC ₂ as a supercapacitor electrode presents a high power density (2416 W kg ^-1 ), high energy density (161 Wh kg ^-1 ), and long cycle life over 4000 cycles (93 %). These results could lead to the amplification of high-performance supercapacitors in new areas to develop real applications and stimulate the use of the targeted design of coordination polymers without hybridization or compositions with additive materials.
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