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A hindrance to the practical use of sodium-ion batteries is the lack of adequate anode materials. By utilizing the co-intercalation reaction, graphite, which is the most common anode material of lithium-ion batteries, was used for storing sodium ion. However, its performance, such as reversible capacity and coulombic efficiency, remains unsatisfactory for practical needs. Therefore, to overcome these drawbacks, a new carbon material was synthesized so that co-intercalation could occur efficiently. This carbon material has the same morphology as carbon black; that is, it has a wide pathway due to a turbostratic structure, and a short pathway due to small primary particles that allows the co-intercalation reaction to occur efficiently. Additionally, due to the numerous voids present in the inner amorphous structure, the sodium storage capacity was greatly increased. Furthermore, owing to the coarse co-intercalation reaction due to the surface pore structure, the formation of solid-electrolyte interphase was greatly suppressed and the first cycle coulombic efficiency reached 80%. This study shows that the carbon material alone can be used to design good electrode materials for sodium-ion batteries without the use of next-generation materials.

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The performance of free-breathing polymer electrolyte membrane fuel cells (PEMFCs) was studied experimentally and the effect of the cathode separator structure on the cell performance was investigated. The result showed that it is difficult to realize a uniform contact pressure across the cell layers for the open type separator, and this results in higher contact resistance and poorer cell performance than the channel type separator.The channel type separator can maintain a low contact resistance, and the cell performance is strongly affected by the natural convection inside the channel. Optimization of the channel design of the channel type separator achieves good performance and this type of separator is superior for a free-breathing PEMFC. A computational three-dimensional analysis for the free-breathing channel type PEMFC with the different channel depths was performed, and it identified the influence of natural convection.

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Background:The elbow plank is a common exercise that can easily be done at home, but its effects on physical fitness and immunocyte function in elderly people are unknown. This prior study was conducted to analyze the changes in health-related physical fitness and immunocytes in an elderly male subject after performing elbow plank exercises. Methods:The participant was a 61-year-old man who had no experience in performing the elbow plank. Elbow plank exercises were performed for 30 min a day, 5 days a week, for 4 weeks. The intensity of was checked daily with ratings of perceived exertion (RPE). His goal was to reach an RPE between 12 and 14, at which a 1 min rest was given before repeating the process with a progressively higher RPE every 10 min.Results: Compared with pre-values, (1) health related physical fitness factors increased after 4 weeks.(2) Body weight, skeletal muscle mass, and basal metabolic rate increased, whereas body fat mass and fat percentage decreased. (3) Certain variables of complete blood count showed positive changes, while others did not. Specifically, NK cells (CD56) and cytotoxicity were improved. Conclusions:This study confirmed that performing elbow plank exercises improved all factors of physical fitness and the immunocyte function in an elderly male. Therefore, 20.73 min (9.27 min of rest) of plank exercise is recommended for elderly men to prevent deterioration of physical fitness and immunocyte function while staying at home, especially during the COVID-19 pandemic.