Hierarchical nanostructures of polypyrrole@MnO2 composite electrodes for high performance solid-state asymmetric supercapacitors

Abstract

A solid-state high performance flexible asymmetric supercapacitor (ASC) was fabricated. Its anode is based on organic-inorganic materials, where polypyrrole (PPy) is uniformly wrapped on MnO2 nanoflowers grown on carbon cloth (CC), and its cathode is made of activated carbon (AC) on CC. The ASC has an areal capacitance of 1.41 F cm(-2) and an energy density of 0.63 mW h cm(-2) at a power density of 0.9 mW cm(-2). An energy storage unit fabricated using multiple ASCs can drive a light-emitting diode (LED) segment display, a mini motor and even a toy car after full charging. The high-performance ASCs have significant potential applications in flexible electronics and electrical vehicles.

A facile one-step approach to hierarchically assembled core–shell-like MnO2@MnO2 nanoarchitectures on carbon fibers: An efficient and flexible electrode material to enhance energy storage

“…MnO 2 NSs with controllable shapes and sizes have been synthesized using different growth methods [32][33][34]. In particular, three-dimensional (3D) flower shaped and hierarchical core-shell-like MnO 2 NSs synthesized by assembling 1D or 2D building blocks (such as nanosheets, nanoparticles, and nanowires) have shown significant enhancement in energy storage properties [35][36][37][38]. Because of their high specific surface area, high porosity, and 3D structures, hierarchical MnO 2 pseudocapacitive materials provide additional electroactive sites with shorter diffusion pathways for ions and electrons.…”

Materials and fabrication of electrode scaffolds for deposition of MnO2 and their true performance in supercapacitors

“…[168,172], well-ordered whisker-like arrays [173], nanorods arrays [170], worm-like amorphous nanowires [171] and nanoflowers [79]. However, the micrometers scale CMFs lack of enough surface area, which leads to thick MnO 2 active layer thus poor MnO 2 utilization in most cases.…”

“…200 mm) [66] and carbon nanofoam paper (230 mm) [46] could afford high MnO 2 mass loading while maintain a reasonable good specific capacitance performance and rate capability. Besides, combining MnO 2 with conducting polymer, like PPy [78,79], to form coreeshell hybrid structures could also achieve high specific capacitances at relatively high MnO 2 mass loadings. Another advantage of architecture-designed MnO 2 when compared with commercial activated carbon electrodes is the high 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64volume normalized capacitance.…”

“…Besides enhancing the electrical conductivity of the electrodes and providing pseudocapacitance, the intermediate conductive polymer shell could also act as sacrificing material for conformal in-situ deposition of MnO 2 [78,82,110,127], while the conductive polymer outer layer could protect the MnO 2 active phase from dissolution in acidic gel electrolyte [79,169]. Thanks to its excellent electrical conductivity, chemical stability and good mechanical flexibility, PEDOT has also been directly employed as a scaffold material [67e69, 190,191].…”

Electropolymerized Polypyrrole Nanocoatings on Carbon Paper for Electrochemical Energy Storage

“…cyclic voltammetry, CV) methods have been developed. [23] PPy films supported on platinum [24] and tantalum sheets from pulse current polymerization, [25] or on stainless steel from galvanostatic and potentiodynamic electropolymerization, [26] have been reported. [20][21][22] Recently, PPy films on different substrates have attained remarkable attention for electrochemical capacitor applications because of their fast electrochemical switching, good redox reversibility, and high pseudoapacitance values.…”