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Polyelectrolyte multilayer films (PEMs) fabricated from the layer-by-layer (LbL) assembly technique have attracted wide interests in the past several decades. Driven and stabilized by electrostatic interaction, the PEMs are sensitive with the external stimuli, contributing to the dynamic tunability of film structures. Compared with adjusting the film structures during assembled procedures, it is more convenient and flexible to control the physical structures of PEMs employing post-treatments. In this review, the different strategies for effectively regulating PEMs’ structures based on the post-treatment, as well as the functionalization of these prepared structural films are discussed. At last, perspectives are provided for the future development directions, aiming to provide opportunities and a novel pathway for microstructural PEMs.

Lithium metal anode (LMA) is a promising candidate for achieving next-generation high-energy-density batteries due to its ultrahigh theoretical capacity and most negative electrochemical potential. However, the practical application of lithium metal battery (LMB) is largely retarded by the instable interfaces, uncontrolled dendrites, and rapid capacity deterioration. Herein, we present a comprehensive overview towards the working principles and inherent challenges of LMAs. Firstly, we diligently summarize the intrinsic mechanism of Li stripping and plating process. The recent advances in atomic and mesoscale simulations which are crucial in guiding mechanism study and material design are also summarized. Furthermore, the advanced engineering strategies which have been proved effective in protecting LMAs are systematically reviewed, including electrolyte optimization, artificial interface, composite/alloy anodes and so on. Finally, we highlight the current limitations and promising research directions of LMAs. This review sheds new lights on deeply understanding the intrinsic mechanism of LMAs, and calls for more endeavors to realize practical Li metal batteries.

Oxygen reduction reaction (ORR) constitutes the core process of many energy storage and conversion devices including metal–air batteries and fuel cells. However, the kinetics of ORR is very sluggish and thus high-performance ORR electrocatalysts are highly regarded. Despite recent progress on minimizing the ORR half-wave potential as the current evaluation indicator, in-depth quantitative kinetic analysis on overall ORR electrocatalytic performance remains insufficiently emphasized. In this paper, a quantitative kinetic analysis method is proposed to afford decoupled kinetic information from linear sweep voltammetry profiles on the basis of the Koutecky–Levich equation. Independent parameters regarding exchange current density, electron transfer number, and electrochemical active surface area can be respectively determined following the proposed method. This quantitative kinetic analysis method is expected to promote understanding of the electrocatalytic effect and point out further optimization direction for ORR electrocatalysis.