Phase-field investigation of lithium electrodeposition under different applied overpotentials and operating temperatures

Despite the high promise, the commercialization of Li-metal-based batteries has been hampered due to the formation of dendrites that lead to mechanical instability, energy loss and eventual internal short circuits. The mechanism of dendrite formation and the strategies to suppress their growth have been studied intensively. However, the effect of applied overpotential and operating temperature on dendrite growth remains to be fully understood. Here, we elucidate the correlation of overpotential and temperature with the surface modulation during electrodeposition using phase-field simulations. We identify an optimal operating temperature of half-cell consisting of a Li metal anode and 1M LiPF6 in EC:DMC(1:1), which increases gradually as the overpotential increases. The investigation reveals that the temperature dependence identified in the simulations and experiments often disagree because they are primarily conducted in galvanostatic and potentiostatic conditions, respectively. The temperature increase under potentiostatic conditions increases the induced current while it decreases the induced overpotential under galvanostatic conditions. Therefore, the analysis and comparison of temperature-dependent characteristics must be carried out with care.

Surface Modulation of Graphene Oxide for Amidase Immobilization with High Loadings for Efficient Biocatalysis

As a type of important and versatile biocatalyst, amidase immobilization on solid materials has received broad attention with its relatively easy procedure and available reusability. However, current porous supports have suffered from limited loadings, and it is highly desired to develop a new type of material with abundant space so as to ensure a high loading of amidase. Here, graphene oxide was adopted as the support for amidase immobilization, which showed the highest loading capacity for amidase (~3000 mg/g) to date. To the best of our knowledge, it is the first case of amidase immobilized on graphene oxide. Through surface modulation via reducing the contents of oxygen-containing functional groups, activity recovery of immobilized amidase increased from 67.8% to 85.3%. Moreover, surface-modulated graphene oxide can efficiently uptake amidase under a wide range of pH, and the maximum loading can reach ~3500 mg/g. The resultant biocomposites exhibit efficient biocatalytic performance for asymmetric synthesis of a chiral amino acid (i.e., L-4-fluorophenylglycine, an intermediate of aprepitant).

A Dual-response Regenerable Luminescent 2D-MOF for Nitroaromatic Sensing via Target-modulation of Active Interaction Sites

Sensitive detection of nitroaromatic compounds is of urgent need due to the serious environmental concerns. Surface modulation is a remarkable approach to alter the accessibility of the active interaction sites...