Seeing Through Muddy Water: Laser-Induced Graphene for Portable Tomography Imaging.

Due to its outstanding physical and chemical properties, graphene synthesized by laser scribing on polyimide (PI) offers excellent opportunities for photothermal applications, antiviral and antibacterial surfaces, and electrochemical storage and sensing. However, the utilization of such graphene for imaging is yet to be explored. Herein, using chemically durable and electrically conductive laser-induced graphene (LIG) for tomography imaging in aqueous suspensions is proposed. These graphene electrodes are designed as impedance imaging units for four-terminal electrical measurements. Using the real-time portable imaging prototypes, the conductive and dielectric objects can be seen in clear and muddy water with equivalent impedance modeling. This low-cost graphene tomography measurement system offers significant advantages over traditional visual cameras, in which the suspended muddy particles hinder the imaging resolution. This research shows the potential of applying graphene nanomaterials in emerging marine technologies, such as underwater robotics and automatic fisheries.

In situ Electrical Impedance Tomography for Visualizing Water Transportation in Hygroscopic Aerogels.

The global water crisis demands immediate attention, and atmospheric water harvesting (AWH) provides a viable alternative. However, studying the real-time subtle relationship between water absorption, diffusion, and internal structure for hygroscopic materials is challenging. Herein, a dynamic visualization technique is proposed that utilizes an in situ electrical impedance tomography (EIT) system and a precise reconstruction algorithm to achieve real-time monitoring of the water sorption process within aerogels from an internal microstructural perspective. These results can be inferred that composites' pore sizes affecting the kinetics of their moisture absorption. In addition, the diffusion path of moisture absorption and the distribution of stored moisture inside aerogels exhibit intrinsic self-selective behavior, where the fiber skeleton of the aerogel plays a crucial role. In summary, this work proposes a generic EIT-based technique for the in situ and dynamic monitoring of the hygroscopic process, pointing to an entirely new approach regarding research on AWH materials.

Multifunctional laser-induced graphene circuits and laser-printed nanomaterials toward non-invasive human kidney function monitoring.

Faced with the increasing prevalence of chronic kidney disease (CKD), portable monitoring of CKD-related biomarkers such as potassium ion (K+), creatinine (Cre), and lactic acid (Lac) levels in sweat has shown tremendous potential for early diagnosis. However, a rapidly manufacturable portable device integrating multiple CKD-related biomarker sensors for ease of sweat testing use has yet to be reported. Here, a portable electrochemical sensor integrated with multifunctional laser-induced graphene (LIG) circuits and laser-printed nanomaterials based working electrodes fabricated by fully automatic laser manufacturing is proposed for non-invasive human kidney function monitoring. The sensor comprises a two-electrode LIG circuit for K+ sensing, a three-electrode LIG circuit with a Kelvin compensating connection for Cre and Lac sensing, and a printed circuit board based portable electrochemical workstation. The working electrodes containing Cu and Cu2O nanoparticles fabricated by two-step laser printing show good sensitivity and selectivity toward Cre and Lac sensing. The sensor circuits are fabricated by generating a hydrophilic-hydrophobic interface on a patterned LIG through laser. This sensor recruited rapid laser manufacturing and integrated with multifunctional LIG circuits and laser-printed nanomaterials based working electrodes, which is a potential kidney function monitoring solution for healthy people and kidney disease patients.

High-Throughput Automatic Laser Printing Strategy toward Cost-effective Portable Integrated Urea Tele-Monitoring System.

A portable sweat urea sensing system is a promising solution to satisfy the booming requirement of kidney function tele-monitoring. However, the complicated manufacturing route and the cumbersome electrochemical testing system still need to be improved to develop the urea point-of-care testing (POCT) and tele-monitoring devices. Here, a universal technical route based on a high-throughput automatic laser printing strategy for fabricating the portable integrated urea monitoring system is proposed. This integrated system includes a high-performance laser-printed urea sensing electrode, a planar three-electrode system, and a self-developed wireless mini-electrochemical workstation. A precursor donor layer is activated by laser scribing and in situ transferred into functional nanoparticles for the drop-on-demand printing of the urea sensing electrode. The obtained electrodes show high sensitivity, low detection limit, fast response time, high selectivity, good average recovery, and long-term stability for urea sensing. Additionally, a laser-induced graphene circuit-based miniature planar three-electrode system and a wireless mini-electrochemical workstation are designed for sensing data collection and transmitting, achieving real-time urea POCT and tele-monitoring. This scalable method provides a universal solution for high-throughput and ultra-fast fabrication of urea-sensing electrodes. The portable integrated urea monitoring system is a competitive option to achieve cost-effective POCT and tele-monitoring for kidney function.

Regulating Lithium Transfer Pathway to Avoid Capacity Fading of Nano Si Through Sub-Nano Scale Interfused SiOx /C Coating.

Si nanoparticles (NPs) are considered as a promising high-capacity anode material owing to their ability to prevent mechanical failure from drastic volume change during (de)lithiation. However, upon cycling, a quick capacity fading is still observed for Si NPs, and the underlying mechanism remains elusive. In this contribution, it is demonstrated that the quick capacity fading is mainly caused by the generation of dead (electrochemically inert) Si with blocked electron conductivity in a densely composited Si/SEI (solid electrolyte interface) hybrid. This is due to the combined influence of electrolyte-related side reactions and the accompanied agglomeration of Si NPs. A compact, sub-nano scale interfused SiOx /C composite coating onto the Si NPs is constructed, and a highly stabilized electrochemistry is achieved upon long cycling. The SiOx /C coating with electron/ion dual transport paths and robust mechanical flexibility enables a fast and stable lithium ion/electron dual diffusion pathway towards the encapsulated Si. With fast reaction kinetics, stable SEI, and an antiagglomeration feature, the obtained Si@SiOx /C composite demonstrates a stable high capacity. This work unravels new perspectives on the capacity fading of Si NPs and provides an effective encapsulating method to remedy the structure degradation and capacity fading of nano Si.

Laser-Induced Transfer of Functional Materials.

Patterning is crucial for the large-scale application of functional materials. Laser-induced transfer is an emerging patterning method for additively depositing functional materials to the target acceptor. With the rapid development of laser technologies, this laser printing method emerges as a versatile method to deposit functional materials in either liquid or solid format. The emerging applications such as solar interfacial evaporation, solar cells, light-emitting diodes, sensors, high-output synthesis, and other fields are rising fields benefiting from laser-induced transfer. Following a brief introduction to the principles of laser-induced transfer, this review will comprehensively deliberate this novel additive manufacturing method, including preparing the donor layer and the applications, advantages, and limitations of this technique. Finally, perspectives for handling current and future functional materials using laser-induced transfer will also be discussed. Non-experts in laser technologies can also gain insights into this prevailing laser-induced transfer process, which may inspire their future research.

Optimization Algorithm of Moving Object Detection Using Multiscale Pyramid Convolutional Neural Networks.

Object detection and recognition is a very important topic with significant research value. This research develops an optimised model of moving target identification based on CNN to address the issues of insufficient positioning information and low target detection accuracy (convolutional neural network). In this article, the target classification information and semantic location information are obtained through the fusion of the target detection model and the depth semantic segmentation model. The classification and position portion of the target detection model is provided by the simultaneous fusion of the image features carrying various information and a pyramid structure of multiscale image features so that the matched image fusion characteristics can be used by the target detection model to detect targets of various sizes and shapes. According to experimental findings, this method's accuracy rate is 0.941, which is 0.189 higher than that of the LSTM-NMS algorithm. Through the migration of CNN and the learning of context information, this technique has great robustness and enhances the scene adaptability of feature extraction as well as the accuracy of moving target position detection.

Cu-Sn Aerogels for Electrochemical CO2 Reduction with High CO Selectivity.

This work reports the synthesis of CuxSny alloy aerogels for electrochemical CO2 reduction catalysts. An in situ reduction and the subsequent freeze-drying process can successfully give CnxSny aerogels with tuneable Sn contents, and such aerogels are composed of three-dimensional architectures made from inter-connected fine nanoparticles with pores as the channels. Density functional theory (DFT) calculations show that the introduction of Sn in Cu aerogels inhibits H2 evolution reaction (HER) activity, while the accelerated CO desorption on the catalyst surface is found at the same time. The porous structure of aerogel also favors exposing more active sites. Counting these together, with the optimized composition of Cu95Sn5 aerogel, the high selectivity of CO can be achieved with a faradaic efficiency of over 90% in a wide potential range (-0.7 V to -1.0 V vs. RHE).

Constructing Sub 10 nm Scale Interfused TiO2/SiOx Bicontinuous Hybrid with Mutual-Stabilizing Effect for Lithium Storage.

TiO2 has been considered as a promising intercalation lithium-ion-battery (LIB) anode material owing to its robust cyclability. However, it suffers from low capacity. Herein, we construct a sub 10 nm scale interfused TiO2/SiOx hybrid with a bicontinuous structure, in which bridged TiO2 nanoparticles (over 80 wt %) are densely packed within a wormlike SiOx network, through the simple oxidation of MAX Ti3SiC2 ceramic. State-of-the-art in situ microscopy characterization unravels a "mutual-stabilizing" effect from the interfused TiO2/SiOx hybrid upon lithiation. That is to say, the two interpenetrated active components restrain the volume expansion of each other with the stress being relieved through abundant interfaces. Meanwhile, the stress generated from one phase functioned as the compressive force on the other phase and vice versa, offsetting the overall volume effect and synergistically reinforcing the structure integrity. Benefiting from the "mutual-stabilizing" effect, the TiO2/SiOx composite manifests a high and stable specific capacity (∼671 mAh g-1 after 580 cycles at 0.1 A g-1) with a low volume expansion of ∼14% even in an extended potential window of 0.01-3.0 V (vs Li+/Li). The concept of mutual-stabilizing effect, in principle, applies to a wide class of interfused bicontinuous hybrids, providing insight into the design of LIB anode materials with high capacity and longevity.

Electrospinning metal Phosphide/Carbon nanofibers from Phytic Acid for hydrogen evolution reaction catalysts.

This paper reports a general electrospinning method to prepare various metal phosphide/carbon nanofibers composite for electrochemical hydrogen evolution reaction (HER) catalysts. An earth-abundant organic acid-phytic acid is successfully incorporated into a conventional electrospinning precursor as the phosphorus source, and continuous nanofibers can be obtained through spinning. After heat treatment, metal phosphide/carbon composite nanofibers can be obtained, with fine phosphide nanoparticles well dispersed on the surface of an interconnected carbon backbone network. Such fibrous structures offer fast charge transfer pathways and enlarged active surface area, which are beneficial for electrocatalysts. As a result, enhance HER catalytic activity can be achieved.

Polyol Solvation Effect on Tuning the Universal Growth of Binary Metal Oxide Nanodots@Graphene Oxide Heterostructures for Electrochemical Applications.

Tuning the uniformity and size of binary metal oxide nanodots on graphene oxide (BMO NDs@GO) is significant but full of challenges in wet-chemistry, owing to the difficulties of controlling the complicated cation/anion co-adsorption, heterogeneous nucleation, and overgrowth processes. Herein, the aim is to tune these processes by understanding the functions of various alcohol solvents for NDs growth on GO. It is found that the polyol solvation effect is beneficial for obtaining highly uniform BMO NDs@GO. Polyol shell capped metal ions exhibit stronger hydrogen-bond interactions with the GO surface, leading to a uniform cation/anion co-adsorption and followed heterogeneous nucleation. The polyol-solvated ions with large diffusion energy barrier drastically limit the ion diffusion kinetics in liquids and at the solid/liquid interface, resulting in a slow and controllable growth. Moreover, the synthesis in polyol systems is highly controllable and universal, thus eleven BMO and polynary metal oxide NDs@GO are obtained by this method. The synthetic strategy provides improved prospects for the manufacture of inorganic NDs and their expanding electrochemical applications.