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The electronic and electrochemical investigations of a Na-adsorbed BC2N/Blue phosphorene van der Waals heterostructure show that it may operate as a promising anode material for sodium-ion batteries.

Extreme precipitation drives a series of natural disasters such as floods, flash floods, landslides, or crop losses. These disasters directly impact people's lives, their homes, and their food security. Located at the edge of the subtropics, on the northern edge of the Sahara desert, Morocco is particularly vulnerable to extreme precipitation. Indeed, between 1951 and 2015, Morocco experienced more than 35 major floods, which resulted in significant material and human losses. Understanding the spatio-temporal characteristics of extreme precipitation is key to better predicting and mitigating the risks associated with extreme precipitation events (EPEs). Yet, the spatio-temporal distribution and physical drivers of extreme precipitation in Morocco remain poorly understood. To address this gap, we apply temporal and spatial clustering methods to precipitation data from the ERA5 database as well as from observational databases to identify the main drivers of EPEs in Morocco. We find that Morocco exhibits five spatially coherent regions in terms of EPE timing, corresponding to mixed influences of large-scale extratropical and tropical weather systems. Indeed, EPEs in northern regions are caused by weather patterns similar to the negative phase of the North Atlantic Oscillation (NAO), associated with strong upper air flow enhanced by Greenland blocking and Rossby wave breaking (RWB). By contrast, extreme precipitation in southern regions is associated with tropical-extratropical interactions. There, EPEs are linked to an intense water vapor transport from the tropics and a relatively weak upper air flow.

Blue phosphorene (Blu-Pn) is a new phosphorene allotrope capable of hosting a substantial amount of sodium (Na) atoms. However, it has been reported to exhibit low electrical conductivity, chemical sensitivity, and structural stability, thus limiting its utility as an anode material for Na-ion batteries (NIBs). In this work, we introduce BC

Rechargeable Potassium and Sodium-ion batteries started to receive a vast amount of attention in recent years against their Lithium-ion counterparts. However, the development of a high-performing anode material for these ion batteries is still to be explored. In this work, we conduct a first-principles study on the adsorption and diffusion behaviors of Potassium (K) and Sodium (Na) in a Graphene/Phosphorene (G/P) van der Waals nano-heterostructure, in order to assess its suitability as an anode for both K-ion and Na-ion batteries. We investigate the electrochemical properties of the system, including binding energies, band structure, ion diffusivity out-side and in-side the G/P system, as well as the heterostructure’s stability at a high metallic coverage. The calculated binding energies for K and Na are −2.69 eV and −2.42 eV, respectively, which are strong enough to prevent metallic clustering during the cycling. The diffusion of K/Na within G/P’s regions shows strong directional anisotropy with a low diffusion barrier of 0.04 eV for K and 0.05 eV for Na along the zigzag direction. We also observe that the addition of K/Na atoms into the G/P system turns its semi-metallic nature into a metallic one. Moreover, we demonstrate that the intercalation of K/Na atoms within the G/P structure give low operating potentials of approximately 0.29 V for K and 0.58 V for Na. Thus, the nano-heterostructure can provide a theoretical storage capacity of 433 mAh/g and 580 mAh/g respectively for K and Na. Finally, the thermal stability of a fully potassiated/sodiated G/P system at room temperature is revealed by the ab-initio Molecular-Dynamics (AIMD) calculations. Considering all these properties, we conclude that the G/P nano-heterostructure can be considered as a good candidate for negative-electrode-materials for both K- and Na-ion batteries.