Energy production and storage technologies have attracted a great deal of attention for day-to-day applications. In recent decades, advances in lithium-ion battery (LIB) technology have improved living conditions around the globe. LIBs are used in most mobile electronic devices as well as in zero-emission electronic vehicles. However, there are increasing concerns regarding load leveling of renewable energy sources and the smart grid as well as the sustainability of lithium sources due to their limited availability and consequent expected price increase. Therefore, whether LIBs alone can satisfy the rising demand for small- and/or mid-to-large-format energy storage applications remains unclear. To mitigate these issues, recent research has focused on alternative energy storage systems. Sodium-ion batteries (SIBs) are considered as the best candidate power sources because sodium is widely available and exhibits similar chemistry to that of LIBs; therefore, SIBs are promising next-generation alternatives. Recently, sodiated layer transition metal oxides, phosphates and organic compounds have been introduced as cathode materials for SIBs. Simultaneously, recent developments have been facilitated by the use of select carbonaceous materials, transition metal oxides (or sulfides), and intermetallic and organic compounds as anodes for SIBs. Apart from electrode materials, suitable electrolytes, additives, and binders are equally important for the development of practical SIBs. Despite developments in electrode materials and other components, there remain several challenges, including cell design and electrode balancing, in the application of sodium ion cells. In this article, we summarize and discuss current research on materials and propose future directions for SIBs. This will provide important insights into scientific and practical issues in the development of SIBs.

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Sodium-ion batteries: present and future

Passive radiative cooling draws heat from surfaces and radiates it into space as infrared radiation to which the atmosphere is transparent. However, the energy density mismatch between solar irradiance and the low infrared radiation flux from a near-ambient-temperature surface requires materials that strongly emit thermal energy and barely absorb sunlight. We embedded resonant polar dielectric microspheres randomly in a polymeric matrix, resulting in a metamaterial that is fully transparent to the solar spectrum while having an infrared emissivity greater than 0.93 across the atmospheric window. When backed with a silver coating, the metamaterial shows a noontime radiative cooling power of 93 watts per square meter under direct sunshine. More critically, we demonstrated high-throughput, economical roll-to-roll manufacturing of the metamaterial, which is vital for promoting radiative cooling as a viable energy technology.

http://science.sciencemag.org/content/sci/early/2017/02/08/science.aai7899.full.pdf

Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling

Recent developments in phase change materials for energy storage applications: A review

Energy storage technologies, including storage types, categorizations and comparisons, are critically reviewed. Most energy storage technologies are considered, including electrochemical and battery energy storage, thermal energy storage, thermochemical energy storage, flywheel energy storage, compressed air energy storage, pumped energy storage, magnetic energy storage, chemical and hydrogen energy storage. Recent research on new energy storage types as well as important advances and developments in energy storage, are also included throughout.

A review of energy storage types, applications and recent developments

A concentrating solar power (CSP) system converts sunlight into a heat source which can be used to drive a conventional power plant. Thermal energy storage (TES) improves the dispatchability of a CSP plant. Heat can be stored in either sensible, latent or thermochemical storage. Commercial deployment of CSP systems have been achieved in recent years with the two-tank sensible storage system using molten salt as the storage medium. Considerable research effort has been conducted to improve the efficiency of the CSP system and make the cost of electricity comparable to that of the conventional fossil-fuel power plant. This paper provides a comprehensive summary of CSP plants both in operation and under construction. It covers the available technologies for the receiver, thermal storage, power block and heat transfer fluid. This paper also reviews developments in high temperature TES over the past decade with a focus on sensible and latent heat storage. High temperature corrosion and economic aspects of these systems are also discussed.

Review on concentrating solar power plants and new developments in high temperature thermal energy storage technologies

Desulfurization and Autothermal Reforming of Jet-A Fuel to Produce Syngas for Onboard Solid Oxide Fuel Cell Applications


 In this study, a three-dimensional solid oxide fuel cell stack numerical model was developed and validated by experimental data. Five-cell SOFC stacks with different inlet and outlet manifold arrangement were investigated employing the numerical model. The stack polarization curve, current density, temperature, and flow distributions were analyzed. The results show that the effect of different manifold arrangement is almost neglected on the polarization curves and flow distribution. However, the current density and temperature distribution in individual unit of the stack can be influenced by the locations of inlets and outlets in the manifolds. Considering current density and temperature distribution uniformity as well as ease manufacturing and installation, the manifold arrangement with inlets at the top and outlets at the bottom for both fuel and air is recommended for SOFC stacks.

Numerical Simulation of Electrical Performance and Distribution of SOFC Stacks With Different Manifold Arrangement

A heat transfer fluid (HTF) is a major component in the system for concentrating solar power systems (CSP) to make electricity. The HTF carries thermal energy from the solar concentrator to a steam generator. Currently hydrocarbon oils or alkali-nitrate-based eutectic molten-salt mixtures are used as the HTF in CSP systems, but these materials have limited operating temperature range, which limits efficiency. Hydrocarbons are limited to 250 °C and alkali-nitrate salts are stable only below 600 °C. Using abundant inexpensive materials to make an HTF which is stable to 1,300 °C and compatible with a metal housing, like a Hastelloy nickel alloy, is desired. Design rules are given which tell how the desired goals can be met, which leads to mixing abundant ionic chloride salts, like NaCl and KCl, which boil at temperatures higher than 1,400 °C, with low-melting (~200 °C) covalent metal halides, such as AlCl3 or ZnCl2, to give low-melting (m.p. < 250 °C) eutectic mixtures, which are stable at high temperatures. To have negligible corrosion of the metals which house the eutectic, the component eutectic should have more negative reduction potentials than metals in the salt housing. Accordingly, the ternary K–Na–Zn chloride molten-salt mixtures in the alloy metal housing should be stable. However, corrosion of the metal housing is seen, especially at higher temperatures. The corrosion rates of housing alloys in molten salt in the presence of or excluding air have been experimentally determined at different temperatures. Indications are that the corrosion of the metal is not due to the salt itself but dissolved impurities like water and oxygen.

Xinhai Xu

Papers

Desulfurization and Autothermal Reforming of Jet-A Fuel to Produce Syngas for Onboard Solid Oxide Fuel Cell Applications

Numerical Simulation of Electrical Performance and Distribution of SOFC Stacks With Different Manifold Arrangement

Materials Challenges for Concentrating Solar Power

Effect of methanol and ethanol on n-decane pyrolysis process by ReaxFF simulation and experiment validation

Desulfurization of Liquid Phase Jet-A Fuel by Selective Adsorption at Room Temperature