Composite quasi-solid electrolytes usually suffer from reduced safety performance due to the presence of liquid plasticizers and an inherently unsafe polymer matrix. Adding inorganic fillers is an effective strategy to improve the safety performance of quasi-solid electrolytes, but excessive content may block ion transport channels, leading to a decrease in electrochemical performance. Therefore, it is proposed to construct a multi-phase synergistic non-flammable composite quasi-solid electrolyte (MS-NCQE) by combining an intrinsically safe porous composite framework with a Li+ conductive polymer through in-situ solidification technique. Thanks to multi-phase synergistic mechanism, a porous composite framework consisting of ceramic powder as well as a non-flammable polymer matrix enables MS-NCQE to exhibit significantly improved safety properties. At the same time, due to the interaction between the third-phase Li+ conductive polymer and ceramic powder, MS-NCQE presents excellent lithium ion transport performance (6.59×10−4 S cm−1 at 25°C) and dendrite resistance (0.1 mA cm−2; 3000 h). Further, the as-prepared LiFePO4|Li and LiNi0.83Co0.12Mn0.05O2|Li batteries display outstanding cycling performance. In particular, the capacity retention rate of the LiFePO4|Li battery is approximately 98% after 300 cycles at 0.5 C, and its average Coulombic efficiency is higher than 99.8%. In addition, the pouch cell can work normally and safely under different abuse conditions. This work provides new insights into the design of composite quasi-solid electrolytes with high safety and excellent electrochemical properties.

Solid-state lithium metal batteries are one of the most promising options for next-generation batteries pursuing high-energy density and high-safety. However, the inevitable volatilization of lithium compounds during sintering leads to low relative density and low ionic conductivity of solid-state electrolytes. Herein, the dynamic lithium-compensation mechanism is proposed to facilitate the densification of Ta-substituted garnet-type electrolyte (Li6.5La3Zr1.5Ta0.5O12 (LLZT)) through the reversible manipulating of Li2O atmosphere. Li2ZrO3 is used as mother powder additive, which reacts with Li2O in sintering atmosphere and forms Li6Zr2O7. Li2ZrO3/Li6Zr2O7 buffer pair manipulates the sintering Li2O atmosphere, which is vital for LLZT, within the Li2O partial pressure range corresponding to Li2ZrO3 and Li6Zr2O7. Furthermore, the reversibility mechanism of buffer pair for Li2O absorption and release is revealed. The obtained LLZT exhibits a relative density of over 96

Nickel-rich layered oxide cathode material LiNixCoyMnzO2 (NCM) has emerged as a promising candidate for next-generation lithium-ion batteries (LIBs). These cathode materials possess high theoretical specific capacity, fast electron/ion transfer rate, and high output voltage. However, their potential is impeded by interface instability, irreversible phase transition, and the resultant significant capacity loss, limiting their practical application in LIBs. In this work, a simple and scalable approach is proposed to prepare gradient cathode material (M-NCM) with excellent structural stability and rate performance. Taking advantage of the strong coordination of Ni2+ with ammonia and the reduction reaction of KMnO4, the elemental compositions of the Ni-rich cathode are reasonably adjusted. The resulted gradient compositional design plays a crucial role in stabilizing the crystal structure, which effectively mitigates Li/Ni mixing and suppresses unwanted surficial parasitic reactions. As a result, the M-NCM cathode maintains 98.6% capacity after 200 cycles, and a rapid charging ability of 107.5 mAh g-1 at 15 C. Furthermore, a 1.2 Ah pouch cell configurated with graphite anode demonstrates a lifespan of over 500 cycles with only 8% capacity loss. This work provides a simple and scalable approach for the in situ construction of gradient cathode materials via cooperative coordination and deposition reactions.

A paper-based electrochemical chip with multiple channels was developed for rapid and ultrasensitive detection of multiple heavy metals by using an aptamer competition strategy. Automatic screen printing was used to create microfluidic patterns on the chip, where liquid is self-driven by capillary force without pump assistance from central to the detection areas. When target ions are present in samples, the methylene blue-modified aptamers dissociate from their complementary sequences immobilized on the chip, resulting in a change in the electrochemical signal. Under optimized experimental conditions, the multi-channel paper-based platform demonstrates a wide linear relationship ranging from 10 pmol/L to 1000 nmol/L. The detection limits for Pb2+, Cd2+, AsO2-, and Hg2+ were as low as 1.55 pmol/L, 0.84 pmol/L, 1.18 pmol/L and 1.63 pmol/L (3 sigma), respectively, indicating excellent selectivity. The sensor was successfully utilized to detect four distinct heavy metal ions in crab meat with a recovery rate between 84.79 % and 101.55 %.

Adapting solid-state Li-metal batteries is an attractive way to pursue higher energy density and safety compared to liquid-based ones. With high ionic conductivity and excellent stability with Li, Ta-doped Li7La3Zr2O12 (LLZTO) is an effective option. However, the poor solid-solid interface contact induced by the lithiophobic Li2CO3 layer hinder its practical application. Herein, a versatile strategy is proposed based on the hydrolysis of sodium tetrafluoroborate (NaBF4), aiming to convert the Li2CO3 into multifunctional hybrid layer containing LiF, LiBO2, and NaF. Among them, LiF and LiBO2 serve as the primary Li ion conductors, the introduction of NaF with high surface energy not only enhances the interface wettability, but also further elevates the critical dendrite strength against Li dendrites. All three components serve as excellent electronic insulators, suppressing electron invasion at the interface and preventing Li dendrite growth in the solid electrolyte. As expected, the interfacial impedance of the NaBF4 treated symmetric cell is reduced to 6.0 omega cm2, the critical current density (CCD) comes to 2.0 mA cm-2, and cycles over 3000 h at 0.3 mA cm-2 and 1500 h at 0.5 mA cm-2 respectively. Besides, the modified SSBs matched with LiFePO4 or LiNi0.6Co0.2Mn0.2O2 cathode show great long-term cycling and rate performance. A new strategy based on BF4- hydrolysis is proposed for the Garnet/Li interface. This strategy includes high modulus and Lipophilic NaF to inhibit dendrite growth, and high ion conductivities LiF and LiBO2 to regulate lithium-ion deposition at the interface. Multiple types of functional products cooperate with each other to achieve a stable and low interface resistance interface. image

The solid-state batteries (SSBs) with Li anode present one of the most promising energy storage systems due to their enhanced energy density and safety. However, interfacial problems between Li anode and solid-state electrolyte hinder the advancement of SSBs. Among them, insufficient solid-solid interfacial contact is the main issue, which causes large resistance and hinders Li+ diffusion, leading to current distribution unevenness and lithium dendrites growth. To meet these challenges, a silver/carbon interlayer composed of ultrafine Ag nanoparticles (approximate to 5 nm) grown on COOH-CNTs (nano-Ag@COOH-CNTs) is constructed. In which, nano-Ag is designed to guide homogeneous Li deposition, while CNTs substrate bonds with Li6.5La3Zr1.5Ta0.5O12 (LLZTO) electrolyte by reactions between & horbar;COOH groups and LLZTO alkaline surface, thus transforming loose physical solid-solid contact to chemical bonding contact. In addition, nano-Ag is immobilized by CNTs, avoiding the migration of Li+ implanted nano-Ag during cycling. Therefore, nano-Ag@COOH-CNTs interlayer can boost Li+ transport at LLZTO/Li interface and inhibit Li dendrites, achieving an ultra-low interfacial resistance of 0.25 Omega cm(2), a high critical current density of 1.7 mA cm(-2) and a long cycling over 2155 h at 0.5 mA cm(-2). The modified SSBs with LiNi0.83Co0.12Mn0.05O2 cathode cycles stably over 500 cycles. Moreover, high-loading SSBs operate stably for 85 cycles.

As one of the most promising sodium-ion cathodes, O3-type transition metal layered oxides (NaxTMO2) with high specific capacity and low cost have received intensive attention. However, they still face the issues of slow Na+ transfer kinetics and undesirable phase transitions. In this study, we report a novel Al and Cu dual substitution strategy to prepare a NaNi1/3Fe1/3Mn1/3O2 cathode using a spray drying method. Specifically, Al serves to stabilize the TM-O layer structure, mitigating adverse phase transitions, while Cu contributes additional capacity and enhances air stability. Consequently, the NaNi0.32Fe0.32Mn0.32Al0.02Cu0.02O2 cathode exhibits enlarged Na+ transfer channels, modulated particle morphology and strengthened layer framework. With the enhanced structure, the John-Teller distortion, adverse phase transitions of O'3 and OP2, and intragranular fatigue cracks are effectively suppressed, leading to improved cycle and air stability. The NaNi0.32Fe0.32Mn0.32Al0.02Cu0.02O2 cathode can maintain 81% of its initial specific capacity at 1C rate after 200 cycles and can obtain a specific capacity of 113 mAh/g even at 5C rate. Furthermore, we find that strengthened Na+ transport kinetics promote homogenous Na+ distribution, which can reduce the formation of unstable interphases to achieve more reversible phase transition. This work helps to better unveil the relationship between Na+ transfer kinetics and phase transition, provides new insight for designing high-performance sodium-ion cathodes.

Ultrathin composite solid‐state electrolytes (CSSEs) demonstrate great promise in high‐energy‐density solid‐state batteries due to their ultrathin thickness and good adaptability to lithium metal anodes. However, uncontrolled dendrite growth and performance deterioration caused by the aggregation of inorganic powder restrict the practical application of ultrathin CSSEs. Herein, a flexible, self‐supporting Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZO) ceramic skeleton is prepared by the tape‐casting method. Subsequently, a 12 µm‐thick CSSE with a 3D interconnection structure is achieved through in situ UV curing of ethoxylated trimethylolpropane triacrylate (ETPTA) in a ceramic skeleton (CS‐CSSE). This design includes a sintered LLZO ceramic, which can avoid the uneven distribution of the inorganic phase and regulate ion migration. Meanwhile, the cross‐linked ETPTA polymer electrolyte contributes to lower interfacial impedance. In addition, the continuous two‐phase interface can also provide a fast transmission channel for Li + . As a result, CS‐CSSE demonstrates superior Li + transference number (0.83) and ionic conductivity (1.19 × 10 ‐3 S cm ‐1 ) at 25 °C. As‐prepared Li|LiNi 0.83 Co 0.12 Mn 0.05 O 2 batteries exhibit high discharge specific capacities of 185.4 mAh g ‐1 at 0.1 C and average coulombic efficiency greater than 99%. The pouch cells exhibit high energy densities of 376 Wh Kg ‐1 and 1186 Wh L ‐1 . This work provides new insights into the application of ceramics to high‐energy‐density solid‐state batteries.

Frequency-mixing technology has been widely used to precisely identify magnetic nanoparticles in applications of quantitative biomedical detection in recent years. Examples include immune adsorption, lateral flow assays (LFAs), and biomagnetic imaging. However, the signals of magnetic response generated by adjacent magnetic samples interfere with each other owing to the small spacing between them in applications involving multi-sample detection (such as the LFA and multiplexing detection). Such signal interference prevents the biosensor from obtaining characteristic peaks related to the concentration of adjacent biomarkers from the magnetic response signals. Mathematical and physical models of the structure of sensors based on frequency-mixing techniques were developed. The theoretical model was verified and its key parameters were optimized by using simulations. A new frequency-mixing magnetic sensor structure was then designed and developed based on the model, and the key technical problem of signal crosstalk between adjacent samples was structurally solved. Finally, standard cards with stable magnetic properties were used to evaluate the performance of the sensor, and strips of the gastrin-17 (G-17) LFA were used to evaluate its potential for use in clinical applications. The results show that the minimum spacing between samples required by the optimized sensor to accurately identify them was only about 4-5 mm, and the minimum detectable concentration of G-17 was 11 pg mL-1 . This is a significant reduction in the required spacing between samples for multiplexing detection. The optimized sensor also has the potential for use in multi-channel synchronous signal acquisition, and can be used to detect synchronous magnetic signals in vivo.

Promoting the interfacial Li + transport and suppressing detrimental lithium dendrites are the main challenges for developing practical solid‐state lithium metal batteries. In this respect, interface rationalizing to synergize the enhancement of ion transport and suppression of lithium dendrites is of paramount significance. Herein, a novel strategy is demonstrated to address those issues by a designed multifunctional composite interlayer. The photocrosslinkable polymer is introduced in a scalable elastic skeleton, which promotes the migration and diffusion of Li + . Moreover, adding perfluoropolyether in the interlayer benefits to regulating the formation of LiF‐rich interface, sufficiently suppress the growth of lithium dendrites. Benefitting from the elasticity, high Li + conductivity and the lithium dendrites suppression capability, the interlayer can significantly improve the interfacial performance of the solid electrolyte/lithium interface, thus leading to the greatly enhanced electrochemical performance of solid‐state lithium metal batteries. A high critical current density of 3.6 mA cm −2 and a long cycling life at 1.0 mA cm −2 for >400 h are achieved for the symmetric cells. Besides, when used in a pouch‐type full cell coupled with LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode, a high charged capacity of 3.25 mAh cm −2 can be maintained through 20 cycles, demonstrating its great potentials for practical application.

Garnet-type electrolyte have received a lot of attention due to its high ionic conductivity, wide electro-chemical window, excellent thermal stability and lithium metal stability, which can match high-voltage cathode and lithium metal anode to promote the safety and energy density of the batteries. The preparation of solid electrolytes frequently necessitates high-temperature solid-state reaction method. However, this method would cause volatile lithium compounds, restricting the practical preparation and application of electrolytes. Herein, the impact of Li2CuO2 (LCO) as a sintering additive on the sintering behavior of Ta-doped garnet-type electrolyte (Li6.5La3Zr1.5Ta0.5O12, LLZT) is investigated. LCO plays an auxiliary sintering role to reduce the sintering temperature, and the internal Li2O atmosphere that is provided by LCO helps densification of LLZT. The relative density of LLZT-0.5 LCO is 96.07 %, and its Li-ion conductivity is 3.6 x 10-4 S cm-1. Li symmetric and full batteries show excellent cycling performance. This facile and effective strategy of utilizing sintering additive for low temperature sintering could offer useful ideas for the low-cost fab-rication of LLZT. (c) 2022 Elsevier B.V. All rights reserved.

Solid-state lithium metal batteries (SSLMBs) have caught research interest for their desirable safety and energy density. However, low density, poor uniformity of the solid-state electrolytes (SSEs), and dendrite penetration through the SSEs are the major problems that hinder the progress in SSLMB's development. Herein, a co-doping strategy is proposed for garnet-type electrolyte by utilizing a well-designed lithium rich additive Li2WO4 (LWO) doping into Li6.5La3Zr1.5Ta0.5O12 (LLZT). LWO addition yields a denser and more uniform material by acting as a sintering aid and providing an inner Li2O atmosphere. W substitutes the Zr element and forms Ta and W-doped LLZO, and second phase, which broadens the sintering temperature range of LLZT and avoids abnormal grain growth (AGG). With 2 wt% LWO, LLZT-2LWO has an ionic conductivity of 0.6 mS/cm and a relative density of 98.67%. Moreover, the critical current density (CCD) of LLZT-2LWO reaches 1.0 mA cm2. LLZT-2LWO achieves long cycling stability for 300 h at 0.5 mA cm-2 , showing an excellent dendrite-suppression capability. The full cell matched with LiNi0.6Co0.2Mn0.2O2 and sulfur cathode displays high discharge capacity and cycling stability. This modification strategy has high efficiency and is conducive to large-scale production, which opens a new opportunity for SSLMBs.(c) 2022 Elsevier Ltd. All rights reserved.

In recent years, point-of-care testing (POCT) has become a topical issue. Lateral flow immunoassay strategies based on magnetic nanoparticles (MNPs) are important POCT elements due to their sensitive quantification of biological materials via MNP magnetic field measurement. In this study, we designed a magnetic flux sensor for use in immunomagnetic biosensing platforms, incorporating a mathematical model and computer simulation strategy. The system used field programmable gate array (FPGA) as the control chip, synthesized excitation signals and excited coils to generate excitation magnetic fields. Also, the stepping motor was controlled to drive the test strip at a uniform speed through the sensor detection area. A differential configuration strategy was used for sensor pick-up coils to assess MNP influence on the magnetic flux, which was insensitive to background magnetic interference and common-mode noise. These factors significantly enhanced the signal-to-noise ratio of the sensor. The magnetic flux sensor structure was optimized, and response magnetic field characteristics of MNP on test strips analyzed using finite element analysis (FEA) simulations. System performance was evaluated by testing human chorionic gonadotropin (HCG), which demonstrated a linear performance, with a limit of detection of 0.0098 mIU/mL. This system may be used to identify other target analytes in different application settings.

Solid‐state lithium metal batteries (SSLMBs) are attracting increasing attentions as one of the promising next‐generation technologies due to their high‐safety and high‐energy density. Their practical application, however, is hindered by lithium dendrite growth and propagation in solid‐state electrolytes (SSEs). Herein, an in situ grain boundary modification strategy relying on the reaction between Li 2 TiO 3 (LTO) and Ta‐substituted garnet‐type electrolyte (LLZT) is developed, which forms LaTiO 3 along with lesser amounts of LTO/Li 2 ZrO 3 at the grain boundaries (GBs). The second phases of LTO/Li 2 ZrO 3 inhibit abnormal grain growth. The presence of LaTiO 3 at the GBs reduces electronic conductivity and improves mechanical strength, which can hinder dendrite formation and block lithium dendrite penetration through the LLZT. Moreover, the adjacent grains by LaTiO 3 build a continuous Li + transport path, providing a homogeneous Li + flux throughout the whole LLZT‐4LTO. As a result, symmetric cells of Li | LLZT‐4LTO | Li shows a high critical current density of 1.8 mA cm −2 and a long cycling stability up to 2000 h at 0.3 mA cm −2 . Moreover, the high‐voltage full cells demonstrate remarkable cycling stability and rate performance. It is believed that this novel grain boundary modification strategy can shed light on the constructing of high‐performance SSEs for practical SSLMBs.

In this study, we developed a novel magnetic lateral flow assay based on iron oxide decorated with platinum probes (Fe3O4@Pt) for dual-mode detection of gastrin-17 (G-17), which is one of the main biomarkers for early gastric cancer diagnosis. The probe material exhibits both magnetic properties and peroxidase activity. The peroxidase activity enhances the intensity of the brownish coloring of the Fe3O4@Pt probes on the test strip, with a limit of detection of 10 pg mL(-1) using the naked eye, which is remarkable for colorimetric lateral flow assays. The magnetic property allows the simple separation and enrichment of the sample, and the signal can be read using a magnetic assay reader for quantitative detection. The linear range for G-17 using the magnetic signal was determined as 10 pg mL(-1) to 2200 pg mL(-1), and the calculated limit of detection was as low as 3.365 pg mL(-1), thereby covering the reference range for G-17. Serum samples were used to validate the test strip, which exhibited high sensitivity, high specificity, and consistency with the results obtained by the enzyme-linked immunosorbent assay method. The entire inspection process using this method can produce results within 35 min and it is simple to operate without requiring strict experimental conditions. This dual-mode lateral flow test strip provides a simple, rapid, and quantitative strategy for detecting G-17, and it may also be valuable in other portable diagnostic applications.

Nanomaterials, especially superparamagnetic nanomaterials, have recently played essential roles in point-of-care testing due to their intrinsic magnetic, electrochemical, and optical properties. The inherent superparamagnetism of magnetic nanoparticles makes them highly sensitive for quantitative detection. Among the various magnetic detection technologies, frequency mixing technology (FMT) technology is an emerging detection technique in the nanomedical field. FMT sensors have high potential for development in the field of biomedical quantitative detection due to their simple structure, and they are not limited to the materials used. In particular, they can be applied for large-scale disease screening, early tumor marker detection, and low-dose drug detection. This review summarizes the principles of FMT and recent advances in the fields of immunoadsorption, lateral flow assay detection, magnetic imaging, and magnetic nanoparticles recognition. The advantages and limitations of FMT sensors for robust, ultrasensitive biosensing are highlighted. Finally, the future requirements and challenges in the development of this technology are described. This review provides further insights for researchers to inspire the future development of FMT by integration into biosensing and devices with a broad field of applications in analytical sensing and clinical usage.

Solid‐state batteries (SSBs) promise high energy density and strong safety due to using nonflammable solid‐state electrolytes (SSEs) and high‐capacity Li metal anode. Ta‐substituted Li7La3Zr2O12 (LLZT) SSE possesses superior ionic conductivity and stability with Li metal, yet the interfacial compatibility and lithium dendrite hazards still hinder its applications. Herein, an interfacial engineering is demonstrated by facile acid‐salt (AS) treatment on LLZT, constructing a 3D cross‐linking LiF‐LiCl (CF) network. Such structure facilitates Li wetting via capillary permeation. Notably, CF as electronically insulting phases block the electrons through the interface and ulteriorly suppress the dendrite formation. The assembled Li symmetric cell exhibited a low interfacial impedance (11.6 Ω cm2) and high critical current densities (CCDs) in the time‐constant mode, 1.8 mA cm−2 at 25 °C and 3.6 mA cm−2 at 60 °C, respectively. Meanwhile, by exploring the capacity‐constant mode of CCD measurement, the concept of critical areal capacity (CAC) is first proposed, obtaining its values of ≈0.5 mAh cm−2 at 25 °C and 1.2 mAh cm−2 at 60 °C. Moreover, the safety‐enhanced hybrid SSBs matched with LiFePO4 and LiNi0.6Co0.2Mn0.2O2 deliver a remarkable rate and cycling performances, validating the feasibility of this interfacial engineering in various SSB systems.

Microfluidic paper-based analytical devices (μPADs) have developed rapidly in recent years, because of their advantages, such as small sample volume, rapid detection rates, low cost, and portability. Due to these characteristics, they can be used for in vitro diagnostics in the laboratory, or in the field, for a variety of applications, including food evaluation, disease screening, environmental monitoring, and drug testing. This review will present various detection methods employed by μPADs and their respective applications for the detection of target analytes. These include colorimetry, electrochemistry, chemiluminescence (CL), electrochemiluminescence (ECL), and fluorescence-based methodologies. At the same time, the choice of labeling material and the design of microfluidic channels are also important for detection results. The construction of novel nanocomponents and different smart structures of paper-based devices have improved the performance of μPADs and we will also highlight some of these in this manuscript. Additionally, some key challenges and future prospects for the use of μPADs are briefly discussed.

Recently, lateral flow assay (LFA) for nucleic acid detection has drawn increasing attention in the point-of-care testing fields. Due to its rapidity, easy implementation, and low equipment requirement, it is well suited for use in rapid diagnosis, food authentication, and environmental monitoring under source-limited conditions. This review will discuss two main research directions of lateral flow nucleic acid tests. The first one is the incorporation of isothermal amplification methods with LFA, which ensures an ultra-high testing sensitivity under non-laboratory conditions. The two most commonly used methodologies will be discussed, namely Loop-mediated Isothermal Amplification (LAMP) and Recombinase Polymerase Amplification (RPA), and some novel methods with special properties will also be introduced. The second research direction is the development of novel labeling materials. It endeavors to increase the sensitivity and quantifiability of LFA testing, where signals can be read and analyzed by portable devices. These methods are compared in terms of limits of detection, detection times, and quantifiabilities. It is anticipated that future research on lateral flow nucleic acid tests will focus on the integration of the whole testing process into a microfluidic system and the combination with molecular diagnostic tools such as clustered regularly interspaced short palindromic repeats to facilitate a rapid and accurate test.

Microfluidic paper-based analytical devices (uPADs) have been widely used in point-of-care testing owing to their simple operation, low volume of the sample required, and the lack of the need for an external force. To obtain accurate semi-quantitative or quantitative results, uPADs need to respond to the challenges posed by differences in reaction conditions. In this paper, multi-layer uPADs are fabricated by the imprinting method for the colorimetric detection of C-Reactive Protein (CRP). Different lighting conditions and shooting angles of scenes are simulated in image acquisition, and the detection-related performance of uPADs is improved by using a machine learning algorithm. The You Only Look Once (YOLO) model is used to identify the areas of reaction in uPADs. This model can observe an image only once to predict the objects present in it and their locations. The YOLO model trained in this study was able to identify all the reaction areas quickly without incurring any error. These reaction areas were categorized by classification algorithms to determine the range of risk of CRP concentration. Multi-layer perceptron, convolutional neural network, and residual network algorithms were used for the classification tasks, where the latter yielded the highest accuracy of 96%.