GaNb₁₁O₂₉ Nanowebs as High-Performance Anode Materials for Lithium-Ion Batteries

M–Nb–O compounds have been considered as promising anode materials for lithium-ion batteries (LIBs) because of their high capacities, safety, and cyclic stability. However, very limited M–Nb–O anode materials have been developed thus far. Herein, GaNb₁₁O₂₉ with a shear ReO₃ crystal structure and a high theoretical capacity of 379 mAh g^–1 is intensively explored as a new member in the M–Nb–O family. GaNb₁₁O₂₉ nanowebs (GaNb₁₁O₂₉-N) are synthesized based on a facile single-spinneret electrospinning technique for the first time and are constructed by interconnected GaNb₁₁O₂₉ nanowires with an average diameter of ∼250 nm and a large specific surface area of 10.26 m² g^–1. This intriguing architecture affords good structural stability, restricted self-aggregation, a large electrochemical reaction area, and fast electron/Li⁺-ion transport, leading to a significant pseudocapacitive behavior and outstanding electrochemical properties of GaNb₁₁O₂₉–N. At 0.1 C, it shows a high specific capacity (264 mAh g^–1) with a safe working potential (1.69 V vs Li/Li⁺) and the highest first-cycle Coulombic efficiency in all of the known M–Nb–O anode materials (96.5%). At 10 C, it exhibits a superior rate capability (a high capacity of 175 mAh g^–1) and a durable cyclic stability (a high capacity retention of 87.4% after 1000 cycles). These impressive results indicate that GaNb₁₁O₂₉-N is a high-performance anode material for LIBs

Microfluidic Device for Efficient Airborne Bacteria Capture and Enrichment

Highly efficient capture and enrichment is always the key for rapid analysis of airborne pathogens. Herein we report a simple microfluidic device which is capable of fast and efficient airborne bacteria capture and enrichment. The device was validated with <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Mycobacterium smegmatis</i>. The results showed that the efficiency can reach close to 100% in 9 min. Compared with the traditional sediment method, there is also great improvement with capture limit. In addition, various flow rate and channel lengths have been investigated to obtain the optimized condition. The high capture and enrichment might be due to the chaotic vortex flow created in the microfluidic channel by the staggered herringbone mixer (SHM) structure, which is also confirmed with flow dynamic mimicking. The device is fabricated from polydimethylsiloxane (PDMS), simple, cheap, and disposable, perfect for field application, especially in developing countries with very limited modern instruments