Sodium-ion batteries (SIBs) are reviving and flourishing during last decade, with great potential to be practically applied in large-scale energy storage markets. The rapid progress of SIBs research is primarily focused on electrode, while electrolytes as another indispensable component in SIBs attracts less attention. Indeed, the improvement of electrode performance is arguably correlated with the electrolyte optimization. In conventional lithium-ion batteries (LIBs), ether-based electrolytes are historically supposed to be less practical owing to the insufficient passivation of both anodes and cathodes. As an important class of aprotic electrolytes, ethers have revived with the emerging Li-S and Li-O 2 batteries in recent years, and are even booming in the wave of SIBs. Etherbased electrolytes are unique to enabling these new battery chemistries in terms of producing stable ternary graphite intercalation compound, modifying anode solid electrolyte interphases, reducing the solubility of intermediates, and decreasing polarization. Better still, ether-based electrolytes are compatible with specific inorganic cathodes and could catalyze the assembly of full SIBs prototypes. Furthermore, ether-based solvents are the dominating electrolytes in the research of Na-S and Na-O 2 batteries. This research news article aims to summarize the recent critical reports on ether-based electrolytes in sodium-based batteries, to unveil the uniqueness of ether-based electrolytes to advancing diverse electrode materials, and to shed light on the viability and challenges of etherbased electrolytes in future sodium-based new battery chemistries.

Understanding the atomistic origin of defects in two-dimensional transition metal dichalcogenides, their impact on the electronic properties, and how to control them is critical for future electronics and optoelectronics. Here, we demonstrate the integration of thermochemical scanning probe lithography (tc-SPL) with a flow-through reactive gas cell to achieve nanoscale control of defects in monolayer MoS 2. The tc-SPL produced defects can present either p-or n-type doping on demand, depending on the used gasses, allowing the realization of field effect transistors, and p-n junctions with precise sub-μm spatial control, and a rectification ratio of over 10 4. Doping and defects formation are elucidated by means of X-Ray photoelectron spectroscopy, scanning transmission electron microscopy, and density functional theory. We find that p-type doping in HCl/H 2 O atmosphere is related to the rearrangement of sulfur atoms, and the formation of protruding covalent S-S bonds on the surface. Alternatively, local heating MoS 2 in N 2 produces n-character.

A large effort is underway to investigate the properties of two-dimensional (2D) materials for their potential to become building blocks in a variety of integrated nanodevices. In particular, the ability to understand the relationship between friction, adhesion, electric charges and defects in 2D materials is of key importance for their assembly and use in nano-electro-mechanical and energy harvesting systems. Here, we report on a new oscillatory behavior of nanoscopic friction in continuous polycrystalline MoS2 films for an odd and even number of atomic layers, where odd layers show higher friction and lower work function. Friction force microscopy combined with Kelvin probe force microscopy and X-ray photoelectron spectroscopy demonstrates that an enhanced adsorption of charges and OH molecules is at the origin of the observed increase in friction for 1 and 3 polycrystalline MoS2 layers. In polycrystalline films with an odd number of layers, each crystalline nano-grain carries a dipole due to the MoS2 piezoelectricity, therefore charged molecules adsorb at the grain boundaries all over the surface of the continuous MoS2 film. Their displacement during the sliding of a nano-size tip gives rise to the observed enhanced dissipation and larger nanoscale friction for odd layer-numbers. Similarly, charged adsorbed molecules are responsible for the work function decrease in odd layer-number.