It is well accepted that a lithiophilic interface can effectively regulate Li deposition behaviors, but the influence of the lithiophilic interface is gradually diminished upon continuous Li deposition that completely isolates Li from the lithiophilic metals. Herein, we perform in-depth studies on the creation of dynamic alloy interface upon Li deposition, arising from the exceptionally high diffusion coefficient of Hg in the amalgam solid solution. As a comparison, other metals such as Au, Ag and Zn have typical diffusion coefficients of 10-20 orders of magnitude lower than for Hg in the similar solid solution phases. This difference induced compact Li deposition pattern with an amalgam substrate even with a high areal capacity of 55 mAh cm-2. This finding provides new insight into the rational design of Li anode substrate for the stable cycling of Li metal batteries.

The ever-increasing complexity of environmental pollutants urgently warrants the development of new detection technologies. In this context, sensors based on the optical properties of hydrogels enabling fast and easy in situ detection are attracting increasing attention. Herein, the target recognition and sensing mechanisms of two main types of optical hydrogels (OHs) are reviewed and discussed: photonic crystal hydrogels (PCHs) and fluorescent hydrogels (FHs). For PCHs, the environmental stimulus response, target receptors, inverse opal structures, and molecular imprinting techniques related to PCHs are reviewed and summarized. Furthermore, the different types of fluorophores (i.e., compound probes, biomacromolecules, quantum dots, and luminescent microbes) of FHs are summarized. Finally, the data from 138 papers about different OHs are extracted for secondary statistical analysis. The detection performance and potential of various OH types in different environmental pollutant detection scenarios are evaluated, and compared them to those obtained using the standard detection method. Based on this analysis, some possible development directions are proposed, including the fusion of various OHs, introduction of more hydrogel technologies from the biomedical field to the environmental pollutant detection field, and development of multifunctional sensor arrays.