COMMUNICATION (1 of 7)between safety and performance has been a challenge due to the use of intrinsically flammable organic electrolyte materials. In addition to the high level of recent interest in all-solid-state LIBs, [5][6][7][8] an alternative is to develop battery technologies that use aqueous electrolytes which are intrinsically safe. [9][10][11] Among candidate anode materials for aqueous batteries, Zn is the most active metal that is stable in water and also has one of the highest specific capacities. As an anode Zn has roughly three times the volumetric capacity (5854 mAh cm −3 ) compared to Li (2062 mAh cm −3 ). [12,13] When paired with an oxygen cathode, the theoretical volumetric energy density of a Zn-air battery (4400 Wh L −1 ) approaches that of a Li-S battery (5200 Wh L −1 ). Additional advantages of the Zn-air cell compared to the Li-S cell are that Zn is much more economical than Li [14][15][16] and the battery is safer due to absence of flammable organic liquid, making Zn-based batteries attractive candidates for electric vehicles and large-scale energy storage. There has been recent progress on rechargeable Zn anode materials in neutral or mildly acidic conditions that eliminate concerns of ZnO passivating the Zn surface. [17][18][19] In order for Zn-based aqueous batteries to have higher specific energy than state-of-the-art LIBs, however, an oxygen cathode must be used, [16] which favors alkaline electrolytes (e.g., KOH) to facilitate the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Although developing efficient ORR and OER electrocatalysts could lower the polarization and improve the round trip energy efficiency of Zn-air batteries, their reversibility is mainly limited by the Zn anode, which has received far less attention. [20][21][22][23][24][25] A deeply rechargeable zinc anode in lean alkaline electrolyte (a cell utilizing the minimum amount of electrolyte) is a critical step toward zinc air battery that has not been achieved yet. A few attempts have been made before. [26][27][28] However, to the best of our knowledge, all of the electrochemical data in past reports were obtained in beaker cells (Figure 1) with ZnO saturated electrolyte or a low depth of discharge (DOD), which raises several problems: (1) the amount of electrolyte exceeds the amount of electrode materials by ≈1000 times, which lowers the overall energy density and covers the problem of As an alternative to lithium-ion batteries, Zn-based aqueous batteries feature nonflammable electrolytes, high theoretical energy density, and abundant materials. However, a deeply rechargeable Zn anode in lean electrolyte configuration is still lacking. Different from the solid-to-solid reaction mechanism in lithium-ion batteries, Zn anodes in alkaline electrolytes go through a solid-solute-solid mechanism (Zn-Zn (OH) 4 2− -ZnO), which introduces two problems. First, discharge product ZnO on the surface prevents further reaction of Zn underneath, which leads to low utilization of active material and poor rec...

Wearable strain sensors that detect joint/muscle strain changes become prevalent at human–machine interfaces for full-body motion monitoring. However, most wearable devices cannot offer customizable opportunities to match the sensor characteristics with specific deformation ranges of joints/muscles, resulting in suboptimal performance. Adequate wearable strain sensor design is highly required to achieve user-designated working windows without sacrificing high sensitivity, accompanied with real-time data processing. Herein, wearable Ti3C2Tx MXene sensor modules are fabricated with in-sensor machine learning (ML) models, either functioning via wireless streaming or edge computing, for full-body motion classifications and avatar reconstruction. Through topographic design on piezoresistive nanolayers, the wearable strain sensor modules exhibited ultrahigh sensitivities within the working windows that meet all joint deformation ranges. By integrating the wearable sensors with a ML chip, an edge sensor module is fabricated, enabling in-sensor reconstruction of high-precision avatar animations that mimic continuous full-body motions with an average avatar determination error of 3.5 cm, without additional computing devices.

No abstract

An innovative anode material of lithium-ion battery, Li3VO4/Ti3C2Tx, was synthesized. The overall three-dimensional electronic and ionic transport pathways were formed in anode, which promoted both electron and ion transport during the lithiation and delithiation processes.

A deeply rechargeable zinc anode material with nanoscale pomegranate-structured was designed and synthesized for the high energy aqueous batteries.

Rechargeable batteries using aqueous electrolyte have intrinsically low flammability and are promising alternatives to lithium ion batteries for mid-and large-scale energy storages. Among aqueous battery anode materials, zinc metal stands out because of the highest energies (5846 Ah/L volumetric capacity, 3 times the amount of a lithium metal anode) and an operating potential near the lower limit of water stability window. However, the rechargeability of Zn anodes is hindered by passivation and dissolution problems associated with the solid-solute-solid transformation during cycling. Here we solve both problems simultaneously by designing a distinctive nanostructured zinc anode in which 100 nm ZnO nanoparticles are wrapped and segmented by graphene oxide (GO) sheets. The small size of primary ZnO nanoparticles prevents passivation, while the GO wrap and segmentation confine soluble Zn(OH) 4 2− intermediates from escaping. This lasagna-like nanostructured Zn anode measured a high volumetric capacity of 2308 Ah/L and achieved a remarkable capacity retention of 86% after 150 cycles. In contrast, the open-structured ZnO nanoparticle anode, without the protection of GO, completely died after 90 cycles.

Solid polymer electrolytes (SPEs) have the potential to enhance the safety and energy density of lithium batteries. However, poor interfacial contact between the lithium metal anode and SPE leads to high interfacial resistance and low specific capacity of the battery. In this work, we present a novel strategy to improve this solid–solid interface problem and maintain good interfacial contact during battery cycling by introducing an adaptive buffer layer (ABL) between the Li metal anode and SPE. The ABL consists of low molecular-weight polypropylene carbonate , poly­(ethylene oxide) (PEO), and lithium salt. Rheological experiments indicate that ABL is viscoelastic and that it flows with a higher viscosity compared to PEO-only SPE. ABL also has higher ionic conductivity than PEO-only SPE. In the presence of ABL, the interface resistance of the Li/ABL/SPE/LiFePO4 battery only increased 20% after 150 cycles, whereas that of the battery without ABL increased by 117%. In addition, because ABL makes a good solid–solid interface contact between the Li metal anode and SPE, the battery with ABL delivered an initial discharge specific capacity of >110 mA·h/g, which is nearly twice that of the battery without ABL, which is 60 mA·h/g. Moreover, ABL is able to maintain electrode–electrolyte interfacial contact during battery cycling, which stabilizes the battery Coulombic efficiency.

An ideal anti‐counterfeiting technology is desired to be unclonable, nondestructive, mass‐producible, and accompanied with fast and robust authentication under various external influences. Although multiple anti‐counterfeiting technologies have been reported, few meet all of the above‐mentioned features. Herein, a mechanically driven patterning process is reported to produce higher dimensional Ti3C2Tx MXene topographies in a scalable yet unclonable manner, which can be used as anti‐counterfeiting tags. By using a high‐speed confocal laser microscopy, the complex topographies can be extracted within one minute and then reconstructed into 3D physical unclonable function (PUF) keys. Meanwhile, a Siamese neural network model and a feature‐tracking software are built to achieve a pick‐and‐check strategy, enabling highly accurate, robust, disturbance‐insensitive tag authentication in practical exploitations. The 3D PUF key‐based anti‐counterfeiting technology features with several advances, including ultrahigh encoding capacities (≈10144 000‐107 800 000), fast processing times (<1 min), and high authentication accuracy under various external disturbances, including tag rotations (≈0°‒360°), tag dislocation(s) in x(y) directions (≈0%‒100%), tag shifts in z‐direction (≈0%‒28%), tag tilts (≈0°‒5°), differences in contrasts (20%‒60%) and laser power (6.0‒9.0 µW). The anti‐counterfeiting technology promises information security, encoding capacity, and authentication efficiency for the manufacturer‐distributor‐customer distribution processes.