In lithium metal batteries, electrolytes containing a high concentration of salts have demonstrated promising cyclability, but their practicality with respect to the cost of materials is yet to be proved. Here we report a fluorinated aromatic compound, namely 1,2‐difluorobenzene, for use as a diluent solvent in the electrolyte to realize the “high‐concentration effect”. The low energy level of the lowest unoccupied molecular orbital (LUMO), weak binding affinity for lithium ions, and high fluorine‐donating power of 1,2‐difluorobenzene jointly give rise to the high‐concentration effect at a bulk salt concentration near 2 m, while modifying the composition of the solid‐electrolyte‐interphase (SEI) layer to be rich in lithium fluoride (LiF). The employment of triple salts to prevent corrosion of the aluminum current collector further improves cycling performance. This study offers a design principle for achieving a local high‐concentration effect with reasonably low bulk concentrations of salts.

green electric transportation due to its low redox potential (−3.04 V vs standard hydrogen electrode) and unprecedented theoretical capacity (3860 mAh g −1 or 2060 mAh mL −1 ). [1] In spite of these advantages, a substantial gap remains before practical application due to vulnerable dendritic growth during repeated Li deposition and stripping. Dendrite growth causes indiscriminate electrolyte decomposition and dead Li, resulting in inferior charge-discharge reversibility and ultimately severe capacity fading.Li dendrite growth has been described by two models. One is the "space charge" model. This model focuses on ion depletion at the electrode-electrolyte interface; as current density increases, an ion depletion layer on the electrode surface is formed and thickens. [2] In this interfacial evolution, Sand's time, an onset point where an ion depletion layer begins to form, serves as a useful descriptor. Above this point, due to Li ion depletion, Li ions tend to lose their homogeneous distribution in the bulk electrolyte and are rather concentrated toward local spots (so-called surface "tips") with higher electron densities. While this model well explains the behaviors of dendrite growth at different current densities, those at low current densities below Sand's time are described limitedly.The other model focuses on the "uniformity" of the solidelectrolyte-interphase (SEI) layer with respect to morphology and composition, without taking current density into consideration. [3] This model relies on a viewpoint that in the nonuniform SEI layer, Li ion transport becomes uneven over the electrode area, which accelerates dendrite growth and consequently destroys the SEI layer. Therefore, from this model's perspective, success in suppressing dendrite growth depends largely on the uniformity and durability of the SEI layer.Based on the consensus regarding the importance of a uniform SEI layer, numerous approaches have been introduced, including artificial SEI layers, [4] LiNO 3 additives, [5] vinylene carbonate additives, [6,7] fluoroethylene carbonate additives, [8] polymer electrolytes, [9] and high-concentration electrolytes (HCEs). [10][11][12][13] In the case of artificial SEI layers, while their effect is noticeable in the early cycling period, inevitable Lithium metal has been hailed as a key enabler of upcoming rechargeable batteries with high energy densities. Nonetheless, uncontrolled dendritic growth and resulting formation of a nonuniform solid-electrolyte-interphase (SEI) layer constitute an ever-challenging obstacle in long-term cyclability and safety. So far, these drawbacks have been addressed mainly by using noncarbonate electrolytes based on their relatively mild decomposition under reductive environments. Here, toluene as a co-solvent of carbonate-based electrolytes for lithium metal anodes is reported. The electron-donating nature of the methyl group of toluene shifts the reduction of toluene prior to that of commonly used carbonate solvents, resulting in a more uniform and rigid SEI layer. Moreove...

To develop better analytical approaches for future global pandemics, it is widely recognized that sensing materials are necessary that enable molecular recognition and sensor assay development on a much faster scale than currently possible. Previously developed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) point-of-care devices are based on the specific molecular recognition using subunit protein antibodies and protein receptors that selectively capture the viral proteins. However, these necessarily involve complex and lengthy development and processing times and are notoriously prone to a loss of biological activity upon sensor immobilization and device interfacing, potentially limiting their use in applications at scale. Here, we report a synthetic strategy for nanoparticle corona interfaces that enables the molecular recognition of SARS-CoV-2 proteins without any antibody and receptor design. Our nanosensor constructs consist of poly(ethylene glycol) (PEG)—phospholipid heteropolymers adsorbed onto near-infrared (nIR) fluorescent single-walled carbon nanotubes (SWCNTs) that recognize the nucleocapsid (N) and spike (S) protein of SARS-CoV-2 using unique three-dimensional (3D) nanosensor interfaces. This results in rapid and label-free nIR fluorescence detection. This antibody-free nanosensor shows up to 50% sensor responses within 5 min of viral protein injections with limit of detection (LOD) values of 48 fM and 350 pM for N and S proteins, respectively. Finally, we demonstrate instrumentation based on a fiber-optic platform that interfaces the advantages of antibody-free molecular recognition and biofluid compatibility in human saliva conditions.

In lithium metal batteries, electrolytes containing a high concentration of salts have demonstrated promising cyclability, but their practicality with respect to the cost of materials is yet to be proved. Here we report a fluorinated aromatic compound, namely 1,2‐difluorobenzene, for use as a diluent solvent in the electrolyte to realize the “high‐concentration effect”. The low energy level of the lowest unoccupied molecular orbital (LUMO), weak binding affinity for lithium ions, and high fluorine‐donating power of 1,2‐difluorobenzene jointly give rise to the high‐concentration effect at a bulk salt concentration near 2 m, while modifying the composition of the solid‐electrolyte‐interphase (SEI) layer to be rich in lithium fluoride (LiF). The employment of triple salts to prevent corrosion of the aluminum current collector further improves cycling performance. This study offers a design principle for achieving a local high‐concentration effect with reasonably low bulk concentrations of salts.

Micrometer‐scale robots capable of navigating enclosed spaces and remote locations are approaching reality. However, true autonomy remains an open challenge despite substantial progress made with externally supervised and manipulated systems. To accelerate the development of autonomous microrobots, alternatives to conventional top‐down lithography are sought. Such additive technologies like printing, coating, and colloidal self‐assembly allow for rapid prototyping and access to novel materials, such as polymers, bio‐ and nanomaterials. On the basis of recent experimental findings that memristive networks can be rapidly printed and lifted off as electronic microparticles, an alternative design paradigm is introduced based on arrays of two‐terminal memristive elements, which enables real‐time use of memory, sensing, and actuation in microrobots. Several memristor‐based designs are validated, each representing a key building block toward robotic autonomy: tracking elapsed time, timestamping a rare event, continuously cataloguing time‐indexed data, and accessing the collected information for a feedback‐controlled response as in a robotic glucose‐responsive insulin. The computational results establish an actionable framework for microrobotic design—tasks normally requiring complex circuits can now be achieved with self‐assembled and printed memristor arrays within microparticles.