Reversible Mn2+/Mn4+ and Mn4+/Mn6+ double-electron redoxes in heterostructure MnS2/MnSe2@HCMs boost high energy storage for hybrid supercapacitors

Abstract

Rational design of electrode materials to refine the specific capacitance, long cycle stability, and energy density of supercapacitors is urgently needed. Herein, using the Mn-based metal organic framework (Mn-MOF) as the precursor, S, Se co-doped hollow porous carbon microspheres encapsulating heterogeneous MnS2/MnSe2 nano-particles (denoted as MnS2/MnSe2@HCMs) have been successfully prepared by a one-step sulfide/selenide reaction. The synergistic effect of reversible Mn2+/Mn4+ and Mn4+/Mn6+ double-electron redoxes improves the electrochemical properties. The lattice defects and defect-induced charge carriers at the interface of the heterostructure promote the adsorption and diffusion of electrolyte ions and improve the conductivity of the electrode. Additionally, the existence of outer S, Se co-doped hollow porous carbon skeleton effectively alleviates volume expansion and improves the wettability of the electrode. Consequently, the MnS2/MnSe2@HCMs electrode presents remarkable specific capacity and cycling stability. Furthermore, the assembled hybrid supercapacitor delivers distinguished energy density, outstanding power density, and long cycle life, presenting a power density range of 1584.6–4732.7 W·kg−1 within an energy density range of 80.9–53.9 Wh·kg−1, and a capacitance retention rate of 80.1% after 10,000 cycles at a current density of 10 A·g−1. This work has created a new idea for designing heterostructure materials, and the prepared materials have significant potential for various applications.