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Lithium–air batteries are considered to be a potential alternative to lithium-ion batteries for transportation applications, owing to their high theoretical specific energy1. So far, however, such systems have been largely restricted to pure oxygen environments (lithium–oxygen batteries) and have a limited cycle life owing to side reactions involving the cathode, anode and electrolyte2,3,4,5. In the presence of nitrogen, carbon dioxide and water vapour, these side reactions can become even more complex6,7,8,9,10,11. Moreover, because of the need to store oxygen, the volumetric energy densities of lithium–oxygen systems may be too small for practical applications12. Here we report a system comprising a lithium carbonate-based protected anode, a molybdenum disulfide cathode2 and an ionic liquid/dimethyl sulfoxide electrolyte that operates as a lithium–air battery in a simulated air atmosphere with a long cycle life of up to 700 cycles. We perform computational studies to provide insight into the operation of the system in this environment. This demonstration of a lithium–oxygen battery with a long cycle life in an air-like atmosphere is an important step towards the development of this field beyond lithium-ion technology, with a possibility to obtain much higher specific energy densities than for conventional lithium-ion batteries. 

Abstract Van der Waals interactions in 2D materials have enabled the realization of nanoelectronics with high‐density vertical integration. Yet, poor energy transport through such 2D–2D and 2D–3D interfaces can limit a device's performance due to overheating. One long‐standing question in the field is how different encapsulating layers (e.g., contact metals or gate oxides) contribute to the thermal transport at the interface of 2D materials with their 3D substrates. Here, a novel self‐heating/self‐sensing electrical thermometry platform is developed based on atomically thin, metallic Ti₃C₂MXene sheets, which enables experimental investigation of the thermal transport at a Ti₃C₂/SiO₂interface, with and without an aluminum oxide (AlO_x) encapsulating layer. It is found that at room temperature, the thermal boundary conductance (TBC) increases from 10.8 to 19.5 MW m⁻²K⁻¹upon AlO_xencapsulation. Boltzmann transport modeling reveals that the TBC can be understood as a series combination of an external resistance between the MXene and the substrate, due to the coupling of low‐frequency flexural acoustic (ZA) phonons to substrate modes, and an internal resistance between ZA and in‐plane phonon modes. It is revealed that internal resistance is a bottle‐neck to heat removal and that encapsulation speeds up the heat transfer into low‐frequency ZA modes and reduces their depopulation, thus increasing the effective TBC. 

Abstract The optimization of traditional electrocatalysts has reached a point where progress is impeded by fundamental physical factors including inherent scaling relations among thermokinetic characteristics of different elementary reaction steps, non‐Nernstian behavior, and electronic structure of the catalyst. This indicates that the currently utilized classes of electrocatalysts may not be adequate for future needs. This study reports on synthesis and characterization of a new class of materials based on 2D transition metal dichalcogenides including sulfides, selenides, and tellurides of group V and VI transition metals that exhibit excellent catalytic performance for both oxygen reduction and evolution reactions in an aprotic medium with Li salts. The reaction rates are much higher for these materials than previously reported catalysts for these reactions. The reasons for the high activity are found to be the metal edges with adiabatic electron transfer capability and a cocatalyst effect involving an ionic‐liquid electrolyte. These new materials are expected to have high activity for other core electrocatalytic reactions and open the way for advances in energy storage and catalysis.