In view of the burgeoning demand for energy storage stemming largely from the growing renewable energy sector, the prospects of high (>300 °C), intermediate (100-200 °C) and room temperature (25-60 ...°C) battery systems are encouraging. Metal sulfur batteries are an attractive choice since the sulfur cathode is abundant and offers an extremely high theoretical capacity of 1672 mA h g
−1
upon complete discharge. Sodium also has high natural abundance and a respectable electrochemical reduction potential (−2.71 V
vs.
standard hydrogen electrode). Combining these two abundant elements as raw materials in an energy storage context leads to the sodium-sulfur battery (NaS). This review focuses solely on the progress, prospects and challenges of the high and intermediate temperature NaS secondary batteries (HT and IT NaS) as a whole. The already established HT NaS can be further improved in terms of energy density and safety record. The IT NaS takes advantage of the lower operating temperature to lower manufacturing and potentially operating costs whilst creating a safer environment. A thorough technical discussion on the building blocks of these two battery systems is discussed here, including electrolyte, separators, cell configuration, electrochemical reactions that take place under the different operating conditions and ways to monitor and comprehend the physicochemical and electrochemical processes under these temperatures. Furthermore, a brief summary of the work conducted on the room temperature (RT) NaS system is given seeking to couple the knowledge in this field with the one at elevated temperatures. Finally, future perspectives are discussed along with ways to effectively handle the technical challenges presented for this electrochemical energy storage system.
This comprehensive review focuses on the progress, prospects and challenges of the high and intermediate NaS secondary batteries (HT and IT NaS) as a whole.
Providing an efficacious plasma facing surface between the extreme plasma heat exhaust and the structural materials of nuclear fusion devices is a major challenge on the road to electricity ...production by fusion power plants. The performance of solid plasma facing surfaces may become critically reduced over time due to progressing damage accumulation. Liquid metals, however, are now gaining interest in solving the challenge of extreme heat flux hitting the reactor walls. A key advantage of liquid metals is the use of vapour shielding to reduce the plasma exhaust. Here we demonstrate that this phenomenon is oscillatory by nature. The dynamics of a Sn vapour cloud are investigated by exposing liquid Sn targets to H and He plasmas at heat fluxes greater than 5 MW m
. The observations indicate the presence of a dynamic equilibrium between the plasma and liquid target ruled by recombinatory processes in the plasma, leading to an approximately stable surface temperature.Vapour shielding is one of the interesting mechanisms for reducing the heat load to plasma facing components in fusion reactors. Here the authors report on the observation of a dynamic equilibrium between the plasma and the divertor liquid Sn surface leading to an overall stable surface temperature.
A steady-state high-flux H or He plasma beam was balanced against the pressure of a Sn vapor cloud for the first time, resulting in a self-regulated heat flux intensity near the liquid surface. A ...temperature response of the liquid surface characterized by a decoupling from the received heating power and significant cooling of the plasma in the neutral Sn cloud were observed. The plasma heat flux impinging on the target was found to be mitigated, as heat was partially dissipated by volumetric processes in the vapor cloud rather than wholly by surface effects. These results motivate further exploration of liquid metal solutions to the critical challenge of heat and particle flux handling in fusion power plants.
Journal of Physics D: Applied Physics published the first Plasma Roadmap in 2012 consisting of the individual perspectives of 16 leading experts in the various sub-fields of low temperature plasma ...science and technology. The 2017 Plasma Roadmap is the first update of a planned series of periodic updates of the Plasma Roadmap. The continuously growing interdisciplinary nature of the low temperature plasma field and its equally broad range of applications are making it increasingly difficult to identify major challenges that encompass all of the many sub-fields and applications. This intellectual diversity is ultimately a strength of the field. The current state of the art for the 19 sub-fields addressed in this roadmap demonstrates the enviable track record of the low temperature plasma field in the development of plasmas as an enabling technology for a vast range of technologies that underpin our modern society. At the same time, the many important scientific and technological challenges shared in this roadmap show that the path forward is not only scientifically rich but has the potential to make wide and far reaching contributions to many societal challenges.
Research highlights ▶ An outcome instrument with sound clinimetric properties to evaluate changes in frailty is needed. ▶ Frailty level is not equivalent to the sum of its’ components. ▶ Most frailty ...instruments do not include factors in multiple dimensions. ▶ For most frailty instruments only construct validity has been studied. ▶ The Frailty Index seems to be the most suitable instrument to evaluate effect of intervention. ▶ There is a need for more consistency and transparency in frailty research.
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