Engineering homotype heterojunctions in hard carbon to induce stable solid electrolyte interfaces for sodium-ion batteries

Developing effective strategies to improve the initial Coulombic efficiency(ICE)and cycling stability of hard carbon(HC)anodes for sodium-ion batteries is the key to promoting the commercial application of HC.In this paper,homotype heterojunctions are designed on HC to induce the generation of stable solid electrolyte interfaces,which can effectively increase the ICE of HC from 64.7%to 81.1%.The results show that using a simple surface engineering strategy to construct a homotypic amorphous Al_(2)O_(3) layer on the HC could shield the active sites,and further inhibit electrolyte decomposition and side effects occurrence.Particularly,due to the suppression of continuous decomposition of NaPF 6 in ester-based electrolytes,the accumulation of NaF could be reduced,leading to the formation of thinner and denser solid electrolyte interface films and a decrease in the interface resistance.The HC anode can not only improve the ICE but elevate its sodium storage performance based on this homotype heterojunction composed of HC and Al_(2)O_(3).The optimized HC anode exhibits an outstanding reversible capacity of 321.5mAhg^(−1) at 50mAg^(−1).The cycling stability is also improved effectively,and the capacity retention rate is 86.9%after 2000 cycles at 1Ag^(−1) while that of the untreated HC is only 52.6%.More importantly,the improved sodium storage behaviors are explained by electrochemical kinetic analysis.

Rapid Survey of Total Protein Content in Mycelia of Oyster Mushroom Based on Near Infrared Spectroscopy

Using the total protein content in mycelia of oyster mushroom cultured in plate medium as the index, the spectral information in 1 000-1 799 nm region was collected to establish a quantitative prediction model for the parameters of strains through partial least squares regression combined with chemometrics. The results showed that the optimal spectral pretreatment method was the combination of Savitzky-Golay smoothing＋Savitzky-Golay derivative＋MSC＋Mean-Centefing. Parameters of the quantitative model including RC, SEC, RP, SEP, MF, SEP /SEC were all in the reasonable regions. The correlation coefficient of the real value and predictive value of the model was 0.672 63. The prediction model had better reliability, robustness and predictive effects, so it could be used for protein content detection in mycelia.