Energies

2026 KiB

Open AccessReview

Electrolytes and Interphasial Chemistry in Li Ion Devices

by Kang Xu

Energies 2010, 3(1), 135-154; https://doi.org/10.3390/en3010135 - 26 Jan 2010

Cited by 77 | Viewed by 15575

Since its appearance in 1991, the Li ion battery has been the major power source driving the rapid digitalization of our daily life; however, much of the processes and mechanisms underpinning this newest battery chemistry remains poorly understood. As in any electrochemical device, the major challenge comes from the electrolyte/electrode interfaces, where the discontinuity in charge distribution and extreme disequality in electric forces induce diversified processes that eventually determine the kinetics of Li⁺ intercalation chemistry. This article will summarize the most recent efforts on the fundamental understanding of the interphases in Li ion devices. Emphasis will be placed on the formation chemistry of the so-called “SEI” on graphitic anode, the effect of solvation sheath structure of Li⁺ on the intercalation energy barrier, and the feasibility of tailoring a desired interphase. Biologically inspired approaches to an ideal interphase will also be briefly discussed. Full article

(This article belongs to the Special Issue Lithium-ion Batteries)

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977 KiB

Open AccessReview

Single-Chamber Solid Oxide Fuel Cell Technology—From Its Origins to Today’s State of the Art

by Melanie Kuhn and Teko W. Napporn

Energies 2010, 3(1), 57-134; https://doi.org/10.3390/en3010057 - 15 Jan 2010

Cited by 85 | Viewed by 14612

Abstract

In single-chamber solid oxide fuel cells (SC-SOFCs), both anode and cathode are situated in a common gas chamber and are exposed to a mixture of fuel and oxidant. The working principle is based on the difference in catalytic activity of the electrodes for the respective anodic and cathodic reactions. The resulting difference in oxygen partial pressure between the electrodes leads to the generation of an open circuit voltage. Progress in SC-SOFC technology has enabled the generation of power outputs comparable to those of conventional SOFCs. This paper provides a detailed review of the development of SC-SOFC technology. Full article

(This article belongs to the Special Issue Fuel Cells)

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934 KiB

Open AccessArticle

Continuous Low Cost Transesterification Process for the Production of Coconut Biodiesel

by Gajendra Kumar, D. Kumar, Shailandra Singh, S. Kothari, Sumit Bhatt and Chandra P. Singh

Energies 2010, 3(1), 43-56; https://doi.org/10.3390/en3010043 - 15 Jan 2010

Cited by 39 | Viewed by 12516

Abstract

Biodiesel, or alkyl ester, is an alternative renewable, biodegradable, and non-toxic diesel fuel produced by the catalytic transesterification of vegetable oil. Here we characterize a system for continuous transesterification of vegetable oil using five continuous stirring tank reactors (5CSTRs). We tested residence times of 16–43min, stirring speeds of 200–800rpm, a catalyst concentration (KOH) of 0.25–1 wt% of oil (in gram), different total flow rates of the oil and MeOH, and on the production performance of the 5 stage continuous reactor for transesterification of vegetable oil. Using a molar ratio of oil:methanol of 1:7 and a reaction temperature of 65 °C, we show that a high stirring speed increased the reaction rate, but an excessive stir speed decreased the reaction rate and conversion to biodiesel. Furthermore, a higher catalyst percentage significantly increased the reaction rate and production capacity. A catalyst percentage of 1 wt% of oil gave the best conversion; 99.04 ± 0.05%. The resulting biodiesel esters were characterized for their physical and fuel properties including density, viscosity, iodine volume, acid volume, cloud point, pure point, gross heat of combustion, and volatility. The purity and conversion of the biodiesel was analyzed by HPLC. Full article

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833 KiB

Open AccessReview

Enzymatic Biofuel Cells—Fabrication of Enzyme Electrodes

by Eileen Hao Yu and Keith Scott

Energies 2010, 3(1), 23-42; https://doi.org/10.3390/en3010023 - 11 Jan 2010

Cited by 114 | Viewed by 16822

Abstract

Enzyme based bioelectronics have attracted increasing interest in recent years because of their applications on biomedical research and healthcare. They also have broad applications in environmental monitoring, and as the power source for portable electronic devices. In this review, the technology developed for fabrication of enzyme electrodes has been described. Different enzyme immobilisation methods using layered structures with self-assembled monolayers (SAM) and entrapment of enzymes in polymer matrixes have been reviewed. The performances of enzymatic biofuel cells are summarised. Various approaches on further development to overcome the current challenges have been discussed. This innovative technology will have a major impact and benefit medical science and clinical research, healthcare management, energy production from renewable sources. Full article

(This article belongs to the Special Issue Fuel Cells)

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446 KiB

Open AccessArticle

The Effect of Wind Power Installations on Coastal Tourism

by Meredith Blaydes Lilley, Jeremy Firestone and Willett Kempton

Energies 2010, 3(1), 1-22; https://doi.org/10.3390/en3010001 - 08 Jan 2010

Cited by 78 | Viewed by 16167

Abstract

We surveyed more than 1,000 randomly sampled, out-of-state tourists at Delaware, USA beaches in 2007. After providing respondents with wind turbine project photo-simulations at several distances, we inquired about the effect development would have on visitation. Approximately one-quarter stated that they would switch beaches if an offshore wind project was located 10 km from the coast, with avoidance diminishing with greater distance from shore. Stated avoidance is less than: avoidance with a fossil fuel power plant located the same distance inland; attraction to a beach with offshore wind turbines; and the percentage stating they would likely pay to take a boat tour. Full article

(This article belongs to the Special Issue Wind Energy)

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Energies, Volume 3, Issue 1 (January 2010) – 5 articles , Pages 1-154

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