Dataset Information

3D Hierarchical Co-Al Layered Double Hydroxides with Long-Term Stabilities and High Rate Performances in Supercapacitors.

ABSTRACT: Three-dimensional (3D) flower-like Co-Al layered double hydroxide (Co-Al-LDH) architectures composed of atomically thin nanosheets were successfully synthesized via a hydrothermal method in a mixed solvent of water and butyl alcohol. Owing to the unique hierarchical structure and modification by butyl alcohol, the electrochemical stability and the charge/mass transport of the Co-Al-LDHs was improved. When used in supercapacitors, the obtained Co-Al-LDHs deliver a high specific capacitance of 838 F g^-1 at a current density of 1 A g^-1 and excellent rate performance (753 F g^-1 at 30 A g^-1 and 677 F g^-1 at 100 A g^-1), as well as excellent cycling stability with 95% retention of the initial capacitance even after 20,000 cycles at a current density of 5 A g^-1. This work provides a promising alternative strategy to enhance the electrochemical properties of supercapacitors.

SUBMITTER: Zai J

PROVIDER: S-EPMC6223799 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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3D Hierarchical Co-Al Layered Double Hydroxides with Long-Term Stabilities and High Rate Performances in Supercapacitors.

Zai Jiantao J Liu Yuanyuan Y Li Xiaomin X Ma Zi-Feng ZF Qi Rongrong R Qian Xuefeng X

Nano-micro letters 20161227 2

Three-dimensional (3D) flower-like Co-Al layered double hydroxide (Co-Al-LDH) architectures composed of atomically thin nanosheets were successfully synthesized via a hydrothermal method in a mixed solvent of water and butyl alcohol. Owing to the unique hierarchical structure and modification by butyl alcohol, the electrochemical stability and the charge/mass transport of the Co-Al-LDHs was improved. When used in supercapacitors, the obtained Co-Al-LDHs deliver a high specific capacitance of 838 ...[more]

PMID: 30460317

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Project description:Layered double hydroxides (LDHs) are an ideal platform to host catalytic metal centers for water oxidation (WO) owing to the high accessibility of water to the interlayer region, which makes all centers potentially reachable and activated. Herein, we report the syntheses of three iridium-doped zinc-aluminum LDHs (Ir-LDHs) nanomaterials (1-3, with about 80 nm of planar size and a thickness of 8 nm as derived by field emission scanning electron microscopy and powder X-ray diffraction studies, respectively), carried out in the confined aqueous environment of reverse micelles, through a very simple and versatile procedure. These materials exhibit excellent catalytic performances in WO driven by NaIO4 at neutral pH and 25 °C, with an iridium content as low as 0.5 mol % (∼0.8 wt %), leading to quantitative oxygen yields (based on utilized NaIO4, turnover number up to ∼10,000). Nanomaterials 1-3 display the highest ever reported turnover frequency values (up to 402 min-1) for any heterogeneous and heterogenized catalyst, comparable only to those of the most efficient molecular iridium catalysts, tested under similar reaction conditions. The boost in activity can be traced to the increased surface area and pore volume (>5 times and 1 order of magnitude, respectively, higher than those of micrometric materials of size 0.3-1 μm) estimated for the nanosized particles, which guarantee higher noble metal accessibility. X-ray absorption spectroscopy (XAS) studies suggest that 1-3 nanomaterials, as-prepared and after catalysis, contain a mixture of isolated, single octahedral Ir(III) sites, with no evidence of Ir-Ir scattering from second-nearest neighbors, excluding the presence of IrO2 nanoparticles. The combination of the results obtained from XAS, elemental analysis, and ionic chromatography strongly suggests that iridium is embedded in the brucite-like structure of LDHs, having four hydroxyls and two chlorides as first neighbors. These results demonstrate that nanometric LDHs can be successfully exploited to engineer efficient WOCs, minimizing the amount of iridium used, consistent with the principle of the noble-metal atom economy.

Dataset Information

3D Hierarchical Co-Al Layered Double Hydroxides with Long-Term Stabilities and High Rate Performances in Supercapacitors.

Publications

3D Hierarchical Co-Al Layered Double Hydroxides with Long-Term Stabilities and High Rate Performances in Supercapacitors.

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