1. Setting the Scope of the Challenge 6474 1.1. The Need for Solar Energy Supply and Storage 6474 1.2. An Imperative for Discovery Research 6477 1.3. Scope of Review 6478 2. Large-Scale Centralized Energy Storage 6478 2.1. Pumped Hydroelectric Energy Storage (PHES) 6479 2.2. Compressed Air Energy Storage (CAES) 6480 3. Smaller Scale Grid and Distributed Energy Storage 6481 3.1. Flywheel Energy Storage (FES) 6481 3.2. Superconducting Magnetic Energy Storage 6482 4. Chemical Energy Storage: Electrochemical 6482 4.1. Batteries 6482 4.1.1. Lead-Acid Batteries 6483 4.1.2. Alkaline Batteries 6484 4.1.3. Lithium-Ion Batteries 6484 4.1.4. High-Temperature Sodium Batteries 6484 4.1.5. Liquid Flow Batteries 6485 4.1.6. Metal-Air Batteries 6485 4.2. Capacitors 6485 5. Chemical Energy Storage: Solar Fuels 6486 5.1. Solar Fuels in Nature 6486 5.2. Artificial Photosynthesis and General Considerations of Water Splitting 6486

Solar Energy Supply and Storage for the Legacy and Nonlegacy Worlds

A detailed investigation has been carried out of the structure and electrochemical activity of electrodeposited Ni-Fe films for the oxygen evolution reaction (OER) in alkaline electrolytes. Ni-Fe films with a bulk and surface composition of 40% Fe exhibit OER activities that are roughly 2 orders of magnitude higher than that of a freshly deposited Ni film and about 3 orders of magnitude higher than that of an Fe film. The freshly deposited Ni film increases in activity by as much as 20-fold during exposure to the electrolyte (KOH); however, all films containing Fe are stable as deposited. The oxidation of Ni(OH)2 to NiOOH in Ni films occurs at potentials below the onset of the OER. Incorporation of Fe into the film increases the potential at which Ni(OH)2/NiOOH redox occurs and decreases the average oxidation state of Ni in NiOOH. The Tafel slope (40 mV dec(-1)) and reaction order in OH(-) (1) for the mixed Ni-Fe films (containing up to 95% Fe) are the same as those for aged Ni films. In situ Raman spectra acquired in 0.1 M KOH at OER potentials show two bands characteristic of NiOOH. The relative intensities of these bands vary with Fe content, indicating a change in the local environment of Ni-O. Similar changes in the relative intensities of the bands and an increase in OER activity are observed when pure Ni films are aged. These observations suggest that the OER is catalyzed by Ni in Ni-Fe films and that the presence of Fe alters the redox properties of Ni, causing a positive shift in the potential at which Ni(OH)2/NiOOH redox occurs, a decrease in the average oxidation state of the Ni sites, and a concurrent increase in the activity of Ni cations for the OER.

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An Investigation of Thin-Film Ni–Fe Oxide Catalysts for the Electrochemical Evolution of Oxygen

Advances in electrocatalysis at solid-liquid interfaces are vital for driving the technological innovations that are needed to deliver reliable, affordable and environmentally friendly energy. Here, we highlight the key achievements in the development of new materials for efficient hydrogen and oxygen production in electrolysers and, in reverse, their use in fuel cells. A key issue addressed here is the degree to which the fundamental understanding of the synergy between covalent and non-covalent interactions can form the basis for any predictive ability in tailor-making real-world catalysts. Common descriptors such as the substrate-hydroxide binding energy and the interactions in the double layer between hydroxide-oxides and H---OH are found to control individual parts of the hydrogen and oxygen electrochemistry that govern the efficiency of water-based energy conversion and storage systems. Links between aqueous- and organic-based environments are also established, encouraging the 'fuel cell' and 'battery' communities to move forward together.

Energy and fuels from electrochemical interfaces

Increasing energy demands and environment awareness have promoted extensive research on the development of alternative energy conversion and storage technologies with high efficiency and environmental friendliness. Among them, water splitting is very appealing, and is receiving more and more attention. The critical challenge of this renewable-energy technology is to expedite the oxygen evolution reaction (OER) because of its slow kinetics and large overpotential. Therefore, developing efficient electrocatalysts with high catalytic activities is of great importance for high-performance water splitting. In the past few years, much effort has been devoted to the development of alternative OER electrocatalysts based on transition-metal elements that are low-cost, highly efficient, and have excellent stability. Here, recent progress on the design, synthesis, and application of OER electrocatalysts based on transition-metal elements, including Co, Ni, and Fe, is summarized, and some invigorating perspectives on the future developments are provided.

Transition-Metal (Co, Ni, and Fe)-Based Electrocatalysts for the Water Oxidation Reaction

This article reviews recent significant advances in the field of water splitting. Catalysts play very important roles in two half reactions of water splitting - water reduction and water oxidation. Considering potential future applications, catalysts made of cheap and earth abundant element(s) are especially important for economically viable energy conversion. This article focuses only on catalysts made of cobalt (Co), nickel (Ni) and iron (Fe) elements for water reduction and water oxidation. Different series of catalysts that can be applied in electrocatalytic and photocatalytic water spitting are discussed in detail and their catalytic mechanisms are introduced. Finally, the future outlook and perspective of catalysts made of earth abundant elements will be discussed.

Catalysts made of earth-abundant elements (Co, Ni, Fe) for water splitting: Recent progress and future challenges

Sol-gel derived spinel MxCo3−xO4 (M=Ni, Cu; 0≤x≤1) films and oxygen evolution ☆

A new method for topology identification, bad data detection and state estimation (SE) is proposed in this paper. The method utilizes fuzzy clustering and pattern matching for this purpose. The proposed approach is very efficient and accurate for simple SE and to aid in improving the accuracy and time performance for conventional weighted least squares state estimator (WLSE). In this method, a fuzzy pattern vector is generated based on the analog measurement vector (telemetry data) received. The topology identification and gross errors are detected from difference between the fuzzy pattern vector and the analog measurement data. The gross errors and topology errors in the measurement data are detected and corrected by using the fuzzy pattern vector which can directly be used as good measurement data for SE. The effectiveness of the proposed method is demonstrated on IEEE 14-bus, IEEE 57-bus, practical 75-bus Indian system and IEEE 118-bus systems. The SE results obtained by proposed method are also compared with ANN models reported in the literatures.

Topology identification, bad data processing, and state estimation using fuzzy pattern matching

Cloud computing is an upcoming technology, which has been recently introduced in the field of IT for delivering services that are hosted over the Internet. It is an amalgamation of Grid computing, Utility computing, Autonomic computing, and utilizes the concept of virtualization. It provides on demand service to the users for accessing resources, information, and software as per their needs. With increased popularity, there has been a tremendous increase in the demands of services by the users, which can be fulfilled by effective load balancing techniques. Load balancing allows even distribution of workload across various nodes in the cloud and aims to provide efficient utilization of resources, improving the system performance, minimizing the resource consumption resulting in low energy usage. In this paper, load balancing techniques proposed by researchers have been discussed and studied and a comparative analysis is being provided based on certain parameters.

Load Balancing in Cloud—A Systematic Review

Preparation of electrodeposited thin films of nickel-iron alloys on mild steel for alkaline water electrolysis. Part I: studies on oxygen evolution

LaNiO3 electrodes were prepared, in the form of thin films on platinum by the methods of spray pyrolysis and sequential coating of mixed metal nitrate solutions followed by thermal decomposition. The films were adherent and of p-type semiconducting. Cyclic voltammetric studies indicated the formation of a quasireversible surface redox couple, Ni(iii)/Ni(ii), on these films before the onset of oxygen evolution in 1 m KOH. The anodic Tafel slopes were ∼40 and ∼65 mV decade−1, on the sprayed LaNiO3 film and on the film obtained by a layer method, respectively. The reaction order with respect to OH− was found to be 2.2 on the sprayed oxide film and 1.2 on the layer film. The sprayed oxide film was found to be electrocatalytically more active. It is suggested that the oxygen evolution reaction proceeds on both the film electrodes via the formation of the physisorbed H2O2 as an intermediate in the rate determining step.

J. P. Pandey

Papers

Sol-gel derived spinel MxCo3−xO4 (M=Ni, Cu; 0≤x≤1) films and oxygen evolution ☆

Topology identification, bad data processing, and state estimation using fuzzy pattern matching

Load Balancing in Cloud—A Systematic Review

Preparation of electrodeposited thin films of nickel-iron alloys on mild steel for alkaline water electrolysis. Part I: studies on oxygen evolution

Preparation and characterization of thin films of LaNiO3 for anode application in alkaline water electrolysis