Machine-Learning-Assisted Aggregation-Induced Emissive Nanosilicon-Based Sensor Array for Point-of-Care Identification of Multiple Foodborne Pathogens.

How timely identification and determination of pathogen species in pathogen-contaminated foods are responsible for rapid and accurate treatments for food safety accidents. Herein, we synthesize four aggregation-induced emissive nanosilicons with different surface potentials and hydrophobicities by encapsulating four tetraphenylethylene derivatives differing in functional groups. The prepared nanosilicons are utilized as receptors to develop a nanosensor array according to their distinctive interactions with pathogens for the rapid and simultaneous discrimination of pathogens. By coupling with machine-learning algorithms, the proposed nanosensor array achieves high performance in identifying eight pathogens within 1 h with high overall accuracy (93.75-100%). Meanwhile, Cronobacter sakazakii and Listeria monocytogenes are taken as model bacteria for the quantitative evaluation of the developed nanosensor array, which can successfully distinguish the concentration of C. sakazakii and L. monocytogenes at more than 103 and 102 CFU mL-1, respectively, and their mixed samples at 105 CFU mL-1 through the artificial neural network. Moreover, eight pathogens at 1 × 104 CFU mL-1 in milk can be successfully identified by the developed nanosensor array, indicating its feasibility in monitoring food hazards.

Review on Layered Manganese-Based Metal Oxides Cathode Materials for Potassium-Ion Batteries: From Preparation to Modification.

Potassium-ion battery is rich in resources and cheap in price, in the era of lithium-ion battery commercialization, potassium-ion battery is the most likely to replace it. Based on the classification and summary of electrode materials for potassium-ion batteries, this paper focuses on the introduction of manganese-based oxide KxMnO2. The layered KxMnO2 has a large layer spacing and can be embedded with large size potassium-ions. This paper focuses on the preparation and doping of manganese-based cathode materials for potassium-ion batteries, summarizes the main challenges of KxMnO2-based cathode materials in the current stage of research and further looks into its future development direction.

Strategies for developing layered oxide cathodes, carbon-based anodes, and electrolytes for potassium ion batteries.

Lithium-ion batteries (LIBs) have become the most popular portable secondary energy storage facilities. However, the limited lithium resource results in possible unsustainable development. Potassium-ion batteries (PIBs) are considered promising alternatives to LIBs because of their high resource availability, low cost, and environmentally friendly features. In this field, high energy density layered cathodes and carbon-based anodes are also the main research objectives. However, compared to the most appealing alternative sodium-ion batteries (SIBs), despite having various theoretical advantages, PIBs exhibit poorer electrochemical performance in practice. Their poor capacity retention and narrow working voltage range seriously limit their applications. The performance of the electrodes is usually considered an important factor for battery performance, life, and safety. To solve these problems, many significant research studies have been carried out in the last decade, achieving numerous breakthroughs. Nevertheless, there are still many drawbacks and unclear mechanisms. In this comprehensive review, we examine the current state of high-performance layered oxide cathodes, electrolytes, and carbon-based anodes, to identify potential candidates for PIBs. Our focus lies on their structural characteristics, interface properties, underlying mechanisms, and modification techniques. The viewpoints of these advanced strategies are integrated, and concise development suggestions and strategies are subsequently proposed.

A dual-mode lateral flow immunoassay by ultrahigh signal-to background ratio SERS probes for nitrofurazone metabolites ultrasensitive detection.

In this work, an ultra-sensitive lateral flow immunoassay (LFIA) with SERS/colorimetric dual signal mode was constructed for the detection of nitrofurazone metabolites, an antibiotic prohibited in animal-origin foods. Au@4-MBN@AgNRs nano-sandwich structural signal tag integrates the unique advantages of high signal-to-background ratio and anti-matrix interference through geometric control of SERS tag and nanoengineering adjustment of chemical composition. Under the optimal conditions, the detection limits of nitrofurazone metabolites by SERS/colorimetric dual-mode LFIA were 20 pg/mL (colorimetric mode) and 0.08 pg/mL (SERS mode). Excitingly, the vLOD of the colorimetric signal improved by a factor of 100 compared to Au NPs-based LFIA. In this study, the proposed dual-mode LFIA was successfully applied to the on-site real-time detection of honey, milk powder, and chicken. It is anticipated that with low background interference and anti-matrix interference output signal, our proposed dual-mode strategy can pave an innovative pathway for the fabrication of a powerful biosensor.

Properties of the "Z"-Phase in Mn-Rich P2-Na0.67 Ni0.1 Mn0.8 Fe0.1 O2 as Sodium-Ion-Battery Cathodes.

P2 layered oxides have attracted more and more attention as cathode materials of high-power sodium-ion batteries (SIBs). During the charging process, the release of sodium ions leads to layer slip, which leads to the transformation of P2 phase into O2 phase, resulting in a sharp decline in capacity. However, many cathode materials do not undergo P2 -O2 transition during charging and discharging, but form a "Z" phase. It is proved that the iron-containing compound Na0.67 Ni0.1 Mn0.8 Fe0.1 O2 formed the "Z" phase of the symbiotic structure of the P phase and O phase during high-voltage charging through ex-XRD and HAADF-STEM. During the charging process, the cathode material undergoes a structural change of P2 -OP4 -O2 . With the increase of charging voltage, the O-type superposition mode increases to form an ordered OP4 phase, and the P2 -type superposition mode disappears after further charging to form a pure O2 phase. 57 Fe-Mössbauer spectroscopy revealed that no migration of Fe ions is detected. The O-Ni-O-Mn-Fe-O bond formed in the transition metal MO6 (M = Ni, Mn, Fe) octahedron can inhibit the elongation of the Mn-O bond and improve the electrochemical activity so that P2-Na0.67 Ni0.1 Mn0.8 Fe0.1 O2 has an excellent capacity of 172.4 mAh g-1 and a coulombic efficiency close to 99% at 0.1C.

Optimization of Synergistic Leaching of Valuable Metals from Spent Lithium-Ion Batteries by the Sulfuric Acid-Malonic Acid System Using Response Surface Methodology.

A new environmentally friendly and economical recycling process for extracting metals from spent lithium-ion batteries (LIBs) using sulfuric acid and malonic acid as leaching agents is proposed. By applying Box-Behnken design (BBD) and response surface methodology (RSM) optimization techniques, the global optimal solution of the maximum leaching rate of metals in spent LIBs is realized. The results show that under the optimal conditions of 0.93 M H2SO4, 0.85 M malonic acid, and a liquid/solid ratio of 61 g·L-1, a temperature of 70 °C and 5 vol % of 30% H2O2, 99.79% Li, 99.46% Ni, 97.24% Co, and 96.88% Mn are recovered within 81 min. The error between the theoretical value and the actual value of the metal leaching rate predicted by the regression model is less than 1.0%. Additionally, the study of leaching kinetics reveals that the leaching process of Li, Ni, Co, and Mn in spent cathode materials was affected by the synergistic effect of interfacial mass transfer and solid product layer diffusion. Economic analysis reveals that evaluation index should be fully considered when formulating recovery processes for different metals. This process can reduce the environmental risks of heavy metal disposal and allow the reuse of metals recovered from spent LIBs.

Ingeniously Designed Yolk-Shell-Structured FeSe2@NDC Nanoboxes as an Excellent Long-Life and High-Rate Anode for Half/Full Na-Ion Batteries.

Thanks to their high conductivity and theoretical capacity, transition metal selenides have demanded significant research attention as prospective anodes for sodium-ion batteries. Nevertheless, their practical applications are hindered by finite cycle life and inferior rate performance because of large volume expansion, polyselenide dissolution, and sluggish dynamics. Herein, the nitrogen-doped carbon (NC)-coated FeSe2 nanoparticles encapsulated in NC nanoboxes (termed FeSe2@NDC NBs) are fabricated through the facile thermal selenization of polydopamine-wrapped Prussian blue precursors. In this composite, the existing nitrogen-doped dual carbon layer improves the intrinsic conductivity and structural integrity, while the unique porous yolk-shell architecture significantly mitigates the volume swelling during the sodium/desodium process. Moreover, the derived Fe-N-C bonds can effectively capture polyselenide, as well as promote Na+ transportation and good reversible conversion reaction. As expected, the FeSe2@NDC NBs deliver remarkable rate performance (374.9 mA h g-1 at 10.0 A g-1) and long-cycling stability (403.3 mA h g-1 over 2000 loops at 5.0 A g-1). When further coupled with a self-made Na3V2(PO4)3@C cathode in sodium-ion full cells, FeSe2@NDC NBs also exhibit considerably high and stable sodium-storage performance.

Asymmetric, Flexible Supercapacitor Based on Fe-Co Alloy@Sulfide with High Energy and Power Density.

Electrode materials with high conductivities that are compatible with flexible substrates are important for preparing high-capacitance electrode materials and improving the energy density of flexible supercapacitors. Here, we report the design and fabrication of a new type of flexible electrode based on nanosheet architectures of a Co-Fe alloy (FeCo-A) coated with ternary metal sulfide composites (FeCo-Ss) on silver-sputtered carbon cloth. The high conductivity of the flexible substrate and the iron-cobalt alloy skeleton enables good electron transmission through the material. In particular, the outer FeCo-S layer has an average thickness of ∼30 nm, providing many active sites. This layer also inhibits the oxidation of the alloy. The electrode material is close to 20 nm thick, which limits inaccessible volumes and promotes high utilization of FeCo-alloy@FeCo-sulfide (FeCo-A-S). The additive-free FeCo-A-S electrode has a high specific capacitance of 2932.2 F g-1 at 1.0 A g-1 and a superior rate capability. All-solid-state supercapacitors based on these electrodes have a high power density of 8000 W kg-1 and a high energy density of 46.1 W h kg-1.

Rational Design of Yolk-Shell ZnCoSe@N-Doped Dual Carbon Architectures as Long-Life and High-Rate Anodes for Half/Full Na-Ion Batteries.

Transition-metal selenides (TMSs) have emerged as prospective anode materials for sodium ion batteries (SIBs), owing to their considerable theoretical capacity and intrinsic high electronic conductivity. Whereas, TMSs still suffer from poor rate capability and inferior cycling stability induced by sluggish kinetics and severe volume changes during de/sodiation processes. Herein, a hierarchical composite consisting of a zinc-cobalt bimetallic selenide yolk and nitrogen-doped double carbon shell (denoted as ZnCoSe@NDC) is engineered and fabricated successfully. The architecture of the as-fabricated material improves the Na-ion storage performance via increasing the electron transfer kinetics, accommodating volume expansion, and mitigating the generation of by-products. As expected, the ZnCoSe@NDC electrode delivers superior sodium storage performance with long cycling stability (344.5 mAh g-1 at 5.0 A g-1 over 2000 long-term cycles) and high-rate performance (319.2 mAh g-1 at 10.0 A g-1 ). Meanwhile, the NVP@C//ZnCoSe@NDC full SIB cells are constructed successfully, retaining 96.3% of its initial capacity at 0.5A g-1 after 200 loops. The outstanding electrochemical performance and the construction of hybrid SIBs will have far-reaching influences on the development of the various rechargeable batteries.

Improving the electrochemical performance of layered cathode oxide for sodium-ion batteries by optimizing the titanium content.

P2-type transition metal oxides are promising cathode materials for sodium-ion batteries. However, due to irreversible phase transition, these batteries exhibit low capacity and poor cycling stability. In this study, highly dense, spherical P2-type oxides Na0.67[Ni0.167Co0.167Mn0.67]1-xTixO2 (0 ≤ x ≤ 0.4) are synthesized by calcining a mixture of Na2CO3, spherical ternary precursor powder Ni0.167Co0.167Mn0.67O2, and different amounts of nanoscale TiO2. High-temperature X-ray diffraction results obtained during calcination reveal 850 °C as the optimum calcination temperature. All materials exhibit high crystallinity without any impurity phases. The initial reversible capacities of the as-prepared samples decrease with increasing Ti substitution; however, these samples attain better cycling stability. When x = 0.2, the sample delivers an initial discharge capacity of 138 mAh g-1 at 20 mA g-1 between 2 and 4.5 V. Even at 100 mA g-1, the sample delivers 101 mAh g-1 reversible capacity in the first cycle with capacity retention of 89.4% after 300 cycles. Moreover, the material shows sloping potential profiles, with the average voltages reaching up to ∼3.8 V. The ex-situ X-ray diffraction (XRD) results of the samples after cycling demonstrate that Ti substitution improves the structural stability. In general, Ti substitution is an effective approach for improving the electrochemical performance of ternary P2-type oxide Na0.67Ni0.167Co0.167Mn0.67O2.