There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Redox‐Based Resistive Switching Memories – Nanoionic Mechanisms, Prospects, and Challenges

Electrochemical energy storage technology is based on devices capable of exhibiting high energy density (batteries) or high power density (electrochemical capacitors). There is a growing need, for current and near-future applications, where both high energy and high power densities are required in the same material. Pseudocapacitance, a faradaic process involving surface or near surface redox reactions, offers a means of achieving high energy density at high charge–discharge rates. Here, we focus on the pseudocapacitive properties of transition metal oxides. First, we introduce pseudocapacitance and describe its electrochemical features. Then, we review the most relevant pseudocapacitive materials in aqueous and non-aqueous electrolytes. The major challenges for pseudocapacitive materials along with a future outlook are detailed at the end.

https://hal.archives-ouvertes.fr/hal-01171774/document

Pseudocapacitive oxide materials for high-rate electrochemical energy storage

Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

This article propounds a new strategy of preparing graphene by reducing GO with stannous ions for the synthesis of SnO2/graphene composites. As anode materials for lithium ion batteries, the composites showed good performance. This opens a new approach for the synthesis of graphene/metal-oxide composites with excellent properties.

Fast synthesis of SnO2/graphene composites by reducing graphene oxide with stannous ions

Currently, tremendous attention has been paid to the rational design and synthesis of unique core/shell heterostructures for high-performance supercapacitors. In this work, the unique ZnO@Co3O4 core/shell heterostructures on nickel foam are successfully synthesized through a facile and cost-effective hydrothermal method combined with a short post annealing treatment. Mesoporous Co3O4 nanowires are multidirectional growing on the rhombus-like ZnO nanorods. In addition, the growth mechanism for such unique core/shell heterostructures is also proposed. Supercapacitor electrodes based on the ZnO@Co3O4 and Co3O4 heterostructures on nickel foam are thoroughly characterized. The ZnO@Co3O4 electrode exhibits high capacitance of 1.72 F cm–2 (857.7 F g–1) at a current density of 1 A g–1, which is higher than that of the Co3O4 electrode. Impressively, the capacitance of the ZnO@Co3O4 electrode increases gradually from 1.29 to 1.66 F cm–2 (830.8 F g–1) after 6000 cycles at a high current density of 6 A g–1, indicatin...

High-Performance Supercapacitor Electrode Based on the Unique ZnO@Co3O4 Core/Shell Heterostructures on Nickel Foam

Mass production of single-crystalline CdS nanobelts is achieved by thermal evaporation of CdS powders with the presence of Au catalyst. The as-synthesized CdS nanobelts are usually hundreds of nanometers to tens of micrometers in width, tens of nanometers in thickness, and several hundreds of micrometers in length. CdS nanobelts have a pronounced increase in conductance of up to four orders of magnitude upon exposure to white light, and also very fast response time about 1–3 s. The photoconductivity mechanism of CdS nanobelts is discussed. The results demonstrate the potential of fabricating nanosized photoconductors and optical switches using the integrity of a single CdS nanobelt.

CdS nanobelts as photoconductors

Construction of desirable NiCo2S4 nanotube arrays on nickel foam substrate for pseudocapacitors with enhanced performance

Transition metal nitrates, carbonates, hydroxides, hydroxyoxides, and so forth are often used as solid precursors to synthesize their respective nanostructured metal-oxides after chemical/thermal conversion. However, synthesis of submicrometer uniform crystalline particles of this class of compound intermediates remains as a challenging but less studied area in nanomaterials research. In this work, we report a polyol process for controlled growth of cobalt carbonate (CoCO3). A preparative investigation on morphogenesis of CoCO3 crystals has been carried out, and three types of highly uniform CoCO3 products (i.e., peanut-like, capsule-like, and rhombus crystals) in the submicrometer region have been synthesized at 200 °C under batch conditions. Uniform particles of tricobalt tetroxide (Co3O4) have also been obtained at 300 °C from the CoCO3 submicrometer crystals after thermal transformation in laboratory air. The Co3O4 powder products possess mesoporosity and essentially preserve the pristine morphologies...

Taihong Wang

Papers

Fast synthesis of SnO2/graphene composites by reducing graphene oxide with stannous ions

High-Performance Supercapacitor Electrode Based on the Unique ZnO@Co3O4 Core/Shell Heterostructures on Nickel Foam

CdS nanobelts as photoconductors

Construction of desirable NiCo2S4 nanotube arrays on nickel foam substrate for pseudocapacitors with enhanced performance

Morphogenesis of Highly Uniform CoCO3 Submicrometer Crystals and Their Conversion to Mesoporous Co3O4 for Gas-Sensing Applications