Porous Co3O4 nanowires derived from long Co(CO3)0.5(OH)·0.11H2O nanowires with improved supercapacitive properties

Abstract

Porous Co(3)O(4) nanowires with large aspect ratio have been obtained by annealing long Co(CO(3))(0.5)(OH)·0.11H(2)O precursor nanowires synthesized by a facile hydrothermal method. The results show that the amount of the additive (urea) has an important impact on the morphology of the as-synthesized cobalt-carbonate-hydroxide intermediate, where the uniformity and the overall structure can be controlled by changing the urea concentration. After the heat treatment, the as-obtained phase-pure Co(3)O(4) nanowires with a well retained structure are applied as the electrode material for supercapacitors, and the sample exhibits excellent performance with a high specific capacitance of 240 F g(-1) after 2000 charge/discharge cycles, corresponding to a retention of 98% of the initial capacitance.

NiCo2O4@TiN Core-shell Electrodes through Conformal Atomic Layer Deposition for All-solid-state Supercapacitors

“…Based on their energy storage mechanisms, supercapacitors can generally be classified into two categories: electrical double-layer capacitors (EDLCs) and pseudocapacitors. Carbonaceous materials are often employed in EDLCs to deliver double-layer capacitance through the accumulation of electrostatic charge on the carbon-based electrodes [8,[12][13][14][15][16], while redox-active materials are commonly used in pseudocapacitors to store energy via fast and reversible surface redox reactions [17][18][19][20][21][22]. The growing interest in the latter, which includes conducting polymers and transition metal oxides/hydroxides, is driven by the vastly superior specific capacitance generated by the efficient Faradaic reactions in pseudocapacitors [23][24][25][26].…”

Iodine‐ion‐induced Size‐tunable Co3O4 Nanowires and the Size‐dependent Catalytic Performance for CO Oxidation

“…A prolonged growth time of 12 h, or as much as several days, is needed in the formation of self-assembled structures. [20,27] In contrast, when I À ions were added, Co(OH) 2 -like sheets were formed first (Supporting Information, Figure S2 a, S3). Short nanowires with diameter of 10 nm directly only grew on the edges of the sheets and then, finally, individual nanowires grew orderly without clear lateral fusion.…”

“…Thus the whole evolution process was completed within only 1.5 h, which is significantly faster than anything previously reported. [20,27] According to the hard-soft/ acid-base theory, a Co-I complex is generally stable. Analysis of the X-ray photoelectron spectroscopy (XPS; Figure 2) of Co-(CO 3 Figure S3, we can see the basal spacing of the (0 0 1) planes is larger than that of the standard Co(OH) 2 (Supporting Information, Figure S3).…”

“…[21][22][23][24][25][26] However, to be able to synthesize complex nanostructures of cobalt-based materials, generally high temperature and especially long reaction times are needed. [20,24,27] It was, therefore, necessary to develop a simple and effective method that could to synthesize complex cobalt-based nanostructures on a largescale in a short time. In our strategy, the formation of self-assembled Co(CO 3 ) 0.5 (OH)·0.11 H 2 O structures is faster and strongly depends on the presence of I À ions.…”

“…Shown in Scheme 1 are the differences between the traditional process and I À ions induced self-assembled process and describes how I À ions can change the evolution processes to make the growth faster. In the self-assembled evolution reported previously, [20,27] recrystallization plays a pivotal role in the formation of individual nanocomponents and lateral fusion drives the aggregation of individual nanocomponents in an orderly fashion in the presence [a] Y. …”