Computational Investigation of Carbon Based Anode Materials for Li- and Post-Li- Ion Batteries.

Due to its negligible capacity with respect to sodium intercalation, graphite is not suited as anode material for sodium ion batteries. Hard carbon materials, on the other hand, provide reasonably high capacities at low insertion potential, making them a promising anode materials for sodium (and potassium) ion batteries. The particular nanostructure of these functionalized carbon-based materials has been found to be crucially linked to the material performance. However, there is still a lack of understanding with respect to the functional role of structural units, such as defects, for intercalation and storage. To overcome these problems, the intercalation of Li, Na, and K in graphitic model structures with distinct defect configurations has been investigated by density functional theory. The calculations confirm that defects are able to stabilize intercalation of larger alkali metal contents. At the same time, it is shown that a combination of phonon and band structure calculations are able to explain characteristic Raman features typically observed for alkali metal intercalation in hard carbon, furthermore allowing for the quantification of the alkali metal intercalation inbetween the layers of hard carbon anodes.

The short- and long-term impacts of climate change on the irrigated barley yield in Iran: an application of dynamic ordinary least squares approach.

Given the extensive impacts of climate change on the agricultural sector and their interactions, the climate change is known as one of the main factors influencing agricultural production. The present study aims to explore the short- and long-term impacts of climate change on the yield of irrigated barley in 28 Iranian provinces over the 1999-2015 period. The research uses panel data and dynamic ordinary least squares (DOLS) method. The study also estimated the threshold levels of temperature and rainfall which confirmed an inverted U-shaped relationship between climate change variables and irrigated barley yield. The threshold levels of temperature and rainfall are estimated to be 15.48 °C and 239 mm, respectively; beyond these threshold levels, the increase in temperature and rainfall have negative impact on barley yield in Iran. The long-term elasticity of temperature shows that the yield will be reduced with the increase in temperature in the long run. Same is the case with the precipitation and barley yield. The findings of the study suggest the need of a comprehensive national climate change policy and alignment of sectoral policies with it mitigate and adapt the climate change and global warming. Moreover, it also provided the guidelines for the government and policy-makers to introduce the use of modern eco-friendly and resource saving technologies such as water-saving methods of irrigation, use of fertilizer in required quantities, and improved seeds use. The government should also introduce the climate change awareness programs especially for farmers.