Self-templated Synthesis of Nickel Silicate Hydroxide/Reduced Graphene Oxide Composite Hollow Microspheres as Highly Stable Supercapacitor Electrode Material

Abstract

Nickel silicate hydroxide/reduced graphene oxide (Ni3Si2O5(OH)4/RGO) composite hollow microspheres were one-pot hydrothermally synthesized by employing graphene oxide (GO)-wrapped SiO2 microspheres as the template and silicon source, which were prepared through sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO2 substrate microspheres. The composition, morphology, structure, and phase of Ni3Si2O5(OH)4/RGO microspheres as well as their electrochemical properties were carefully studied. It was found that Ni3Si2O5(OH)4/RGO microspheres featured distinct hierarchical porous morphology with hollow architecture and a large specific surface area as high as 67.6 m2 g–1. When utilized as a supercapacitor electrode material, Ni3Si2O5(OH)4/RGO hollow microspheres released a maximum specific capacitance of 178.9 F g−1 at the current density of 1 A g−1, which was much higher than that of the contrastive bare Ni3Si2O5(OH)4 hollow microspheres and bare RGO material developed in this work, displaying enhanced supercapacitive behavior. Impressively, the Ni3Si2O5(OH)4/RGO microsphere electrode exhibited outstanding rate capability and long-term cycling stability and durability with 97.6% retention of the initial capacitance after continuous charging/discharging for up to 5000 cycles at the current density of 6 A g−1, which is superior or comparable to that of most of other reported nickel-based electrode materials, hence showing promising application potential in the energy storage area.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-017-2094-9) contains supplementary material, which is available to authorized users.

Facile One‐Pot Synthesis of Yolk‐Shell Structured Ni Doped Mesoporous Silica and Its Application in Enzyme‐Free Glucose Sensor

“…During any practical experiments, other easily oxidative species like ascorbic acid (AA), uric acid (UA) dopamine (DA) usually co‐exist with glucose in human blood and interfere in the oxidation of glucose by non‐enzymatic method . The interference test was also carried out with our sample which proves exclusive response of our sample for glucose only.…”

“…On the contrary, for Ni 2p core level electron a pair of several predominant peaks appear near binding energy values ca . 856.8 and 874.3 eV, along with two satellite peaks at ∼862.9 and 880.6 eV (Figure (c)) . These corresponds to the binding energy of Ni 2p 3/2 and Ni 2p 1/2 states, respectively, whereas satellite peaks indicate the spin‐orbit doublets with the BE separation of ∼18.1 eV.…”

Monodispersed Silica@Nickel Silicate Hydroxide Core–Shell Spheres for Supercapacitor Electrodes

“…The corresponding specific capacitance is calculated to be 356.7, 269.8, 202.2, 147.8, and 113.3 F g −1 at the current density of 0.5, 1, 2, 5, and 10 A g −1 , respectively. In addition, compared with other metal silicate compounds as electrodes, the SiNiOH core–shell microspheres display a higher specific capacitance of 269.8 F g −1 at a current density of 1.0 A g −1 .…”

“…A pair of redox peak of all CV curves is distinctly observed which represents the reversible faradaic reaction of nickel ions in alkaline electrolyte. A possible redox reaction is proposed as:…”

“…Among the various electrical energy storage devices used in portable and microelectronic systems, supercapacitors have gained much attention and have turned into hot spots in the electrochemistry field due to their prominent competitiveness in charge–discharge rate, power density, and cycle stability . According to the charge storage mechanisms, the faradic capacitance derived from the reversible redox reactions is much higher when compared with the electrical double‐layer capacitance .…”