A three-dimensional MnO₂/graphene hybrid as a binder-free supercapacitor electrode

Abstract

Highly aligned manganese dioxide (MnO 2 ) nanowall arrays electrodeposited onto Ti sheets are used as substrates to grow graphene (GR) through chemical vapor deposition (CVD), thus forming three-dimensional (3D) MnO 2 /GR hybrid composite.Furthermore, 3D MnO 2 /GR hybrid with different structures and properties has been prepared at different temperatures. The as-prepared hybrid materials could be directly used as supercapacitor electrodes without any binder and conductive additive, and fully maintain the high conductivity and high specific area of GR, large pseudocapacitance of MnO 2 nanowall arrays. In aqueous electrolytes, the hybrids show a high specific capacitance of ~326.33 F g -1 with good cycling stability at the scan rate of 200 mV s -1 and high energy density of 23.68 Wh kg -1 while maintaining high power density of 7270 W kg -1 . The preparation method provides a novel road to fabricate 3D graphene-based composite materials, and the so obtained hybrid electrode demonstrates its potential applications in supercapacitors.

MnO2 decorated on carbon sphere intercalated graphene film for high-performance supercapacitor electrodes

“…226.9 F g -1 and 162.9 F g -1 at 1 A g -1 , 2 A g -1 , 5 A g -1 and 10 A g -1 , respectively, the values are comparable to the previous studies, as shown in Table 1 [27][28][29][30][31][32][33][34][35]. Our 4-µm thick MCG flexible films with a packing density of 0.87 g cm -3 , which leads to a significant gravimetric capacitance of 277.8 F cm -3 , which is much higher than previously reports.…”

Retracted: A concise review on the elastomeric behavior of electroactive polymer materials

“…These authors practiced this scheme in later work altering the silicone matrix employed 5 . The grafting of dipole of N ‐allyl‐ N ‐methyl‐ p ‐nitro aniline to two silicone polymers commercially used (Sylgard 184 from Dow corning and elastosil RT 625 from Wacker) in the concentration range from 0 to 10.7 wt% enhanced the dielectric permittivity from ε = 2.84 to ε = 6.5 for sylgard 184 and from ε = 3.17 to ε = 5.57 for elastosil RT 625 69 and reduced the Young's modulus for sylgard 184 from Y = 2490 to 850 kPa and for elastosil RT 625 from Y = 303 to Y = 142 kPa 69 . The samples with greater dipole behavior values in both silicones demonstrated increased electromechanical efficiency compared to ordinary silicones, although in both cases breakdown value decreased.…”

Birnessite based nanostructures for supercapacitors: challenges, strategies and prospects

“…Carbon based nanomaterials possess lots of advanced properties, including high specic surface area, abound electrochemically active sites, light weight and high electronic conductivity, and were deemed as the most perfect supplementary materials for birnessite based electrode structures. 73,90 Three main kinds of carbon materials, including graphene, [91][92][93][94][95] carbon nanotubes [96][97][98][99][100][101] and porous carbon, [102][103][104] are widely investigated in view of their good electrical conductivity and excellent mechanical/electrochemical stability.…”