No abstract

Heterojunction nanosheets prepared by the HF-assisted hydrothermal synthesis method are composed of TiOF2 and TiO2.

The devices with non-invasive characteristics have aroused people’s wide concern based on sweat analysis, such as providing real-time and accurate test of ethanol concentration. Unfortunately, these devices show limited selectivity, sensitivity, and stability owing to the existing planar electrodes with sluggish mass transport and inefficient active site utilization. The Au NW-gel bioelectrode exhibited good and quick linear current responses toward a broad range of ethanol concentration from 0.01 to 0.5 M. It was validated to an appreciable stability and selectivity to ethanol detection in the existences of sodium chloride, lactic acid, and urea. The abnormal concentration of ethanol in human’s biofluids is the index of unhealthy conditions from internal diseases. Herein, we introduce the application of gold nanowire aerogel (Au NW-gel) in detecting the concentration of ethanol in simulated human sweat. A preparation method based on substrate-assisted growth method is introduced. The length of Au NW synthesized by the substrate-assisted growth method is 10–20 μm. Au NW-gel has an ultralow density and high gold content, which can reduce the internal resistance of the electrode sufficiently. The pore structure of aerogel can accelerate the mass transfer process and make the Au NW-gel have excellent performance. The linear relationship between peak current and ethanol concentration in simulated sweat is established, and the retention capability of the biosensor is more than 83%. Furthermore, a simulation model is developed to validate the robust mass transfer and electrochemical performance of the porous electrode. The Au NW-gel-based electrode provides an effective pathway for detecting the ethanol content in sweat precisely.

LiNi0.8Co0.1Mn0.1O2, one of the typical nickel-rich cathode materials, is considered as a candidate for next generation high energy density Lithium-ion batteries (LIBs) due to its high specific capacity and relatively low cost. But there are still some issues, such as poor cycling performance and thermal stability, to be addressed when charging the nickel-rich cathode materials for LIBs to high cutoff voltage. Therefore, we construct a multifunctional mixed conductive coating layer with polypyrrole and nano titanium nitride particles to improve the comprehensive performance of LiNi0.8Co0.1Mn0.1O2, especially the rate performance and the thermal stability. This mixed coating layer not only inhibits the side reactions at the interface of the active material but also possesses high conductivity as well as the unique elasticity that can release the stress of the cathode during cycling. Comparing with the single polypyrrole coating layer, such a mixed coating layer can ensure the comodified LiNi0.8Co0.1Mn0.1O2 maintaining 80.1% capacity retention after 450 cycles at the upper cutoff voltage of 4.5 V. Besides, it also alleviates the collapse of the secondary particles after long cycles due to its unique elasticity. Meanwhile, the titanium nitride with super high electronic conductivity greatly improves the conductivity of the comodified LiNi0.8Co0.1Mn0.1O2 so that it can still deliver a specific capacity of 102 mAh·g–1 at 20C. What’s more, the thermal stability of the comodified sample is also improved due to the good thermal conductivity and thermal stability characteristics of the titanium nitride as well as the polypyrrole layer. All the results verify that this design is an effective way to enhance the comprehensive properties of Ni-rich cathode materials.