Boosting capacitive performance of manganese oxide nanorods by decorating with three-dimensional crushed graphene

Abstract

This work reports the rational design of MnOx nanorods on 3D crushed reduced graphene oxide (MnOx/C-rGO) by chemical reduction of Ni-incorporated graphene oxide (GO) followed by chemical etching to remove Ni. The resulting MnOx/C-rGO composite synergistically integrates the electronic properties and geometry structure of MnOx and 3D C-rGO. As a result, MnOx/C-rGO shows a significantly higher specific capacitance (Csp) of 863 F g−1 than MnOx/2D graphene sheets (MnOx/S-rGO) (373 F g−1) and MnOx (200 F g−1) at a current density of 0.2 A g−1. Furthermore, when assembled into symmetric supercapacitors, the MnOx/C-rGO-based device delivers a higher Csp (288 F g−1) than MnOx/S-rGO-based device (75 F g−1) at a current density of 0.3 A g−1. The superior capacitive performance of the MnOx/C-rGO-based symmetric device is attributed to the enlarged accessible surface, reduced lamellar stacking of graphene, and improved ionic transport provided by the 3D architecture of MnOx/C-rGO. In addition, the MnOx/C-rGO-based device exhibits an energy density of 23 Wh kg−1 at a power density of 113 Wkg−1, and long-term cycling stability, demonstrating its promising potential for practical application. Graphical Abstract

Wrinkled Flower-Like rGO intercalated with Ni(OH)2 and MnO2 as High-Performing Supercapacitor Electrode

“…The synergistic effect of the MnO 2 and Ni­(OH) 2 decoration in between the rGO layers is mainly responsible for the improved C sp of the ternary hybrid. During the electrochemical process, the presence of pseudocapacitive nanoparticles induces extra energy storing capability by performing the redox reactions shown in eqs and . , Those reactions offer adsorption and desorption of protons and electrolyte cations (Na + of Na 2 SO 4 ) on the Ni­(OH) 2 and MnO 2 , respectively. Hence, it can be demonstrated that the growth of Ni­(OH) 2 and MnO 2 in between the rGO surface facilitates better charge storing capability than pristine rGO …”

“…A disk-shaped graphite plate as a current collector and Whatman filter paper (pore size, 11 μm) as a separator was used. The symmetrical two-electrode cell setup and electrode fabrication process are described in our earlier works. − The specific capacitance ( C sp ), energy density ( E ), and power density ( P ) values of the symmetrical two-electrode system as employed were from the GCD results using the following eqs –: …”

A Facile Fabrication of Ordered Mesoporous Carbons Derived from Phenolic Resin and Mesophase Pitch via a Self-Assembly Method

“…Figure 2 a displays the small-angle XRD patterns of the MCs and OMCs prepared with different amounts of mesophase pitch. The SAXS spectra of MC-meso-10 and OMC-meso-10 exhibited the typical low-angle peaks at 2θ = 0.50° and 0.75°, respectively, indicating an ordered mesoporous structure [ 22 , 23 ]. In particular, the OMC-meso-10 showed sharp intensity, implying a more ordered mesopore structure, whereas the OMC-meso-20 showed rather broad peak due to the weak long-range ordering of its mesopore structure [ 22 , 23 , 24 ].…”

“…The SAXS spectra of MC-meso-10 and OMC-meso-10 exhibited the typical low-angle peaks at 2θ = 0.50° and 0.75°, respectively, indicating an ordered mesoporous structure [ 22 , 23 ]. In particular, the OMC-meso-10 showed sharp intensity, implying a more ordered mesopore structure, whereas the OMC-meso-20 showed rather broad peak due to the weak long-range ordering of its mesopore structure [ 22 , 23 , 24 ]. Meanwhile, the wide-angle XRD patterns of the MCs and OMCs ( Figure 2 b) exhibited broad diffraction peaks at 2θ = 23.5° and 43.2°, corresponding to the (002) and (101) reflections of amorphous carbon, respectively, suggesting that the carbons prepared at a low carbonization temperature of 600 °C had lower crystallinity and thus lower graphitization [ 24 , 25 , 26 , 27 ].…”

Nitrogen-Doped Porous MXene (Ti3C2) for Flexible Supercapacitors with Enhanced Storage Performance

“…Carbon materials, such as graphene (G) [ 14 ], activated carbon (AC) [ 15 ], and carbon nanotubes (CNTs) [ 16 ], have excellent electrical conductivity but limited mass capacitance due to the electrochemical double layer capacitance (EDLC). Transition metal oxides (TMOs) such as MoO 3 [ 17 ], MnO x [ 18 ], V 2 O 5 [ 19 ], and RuO 2 [ 20 ] usually possess incredibly high theoretical specific capacitances. However, sluggish kinetics and poor electrical conductivity lead to severe capacitance fading and jeopardize the commercialization of FSCs.…”