Aprotic Li-O batteries represent promising alternative devices for electrical energy storage owing to their extremely high energy densities. Upon discharge, insulating solid LiO forms on cathode surfaces, which is usually governed by two growth models, namely the solution model and the surface model. These LiO growth models can largely determine the battery performances such as the discharge capacity, round-trip efficiency and cycling stability. Understanding the LiO formation mechanism and controlling its growth are essential to fully realize the technological potential of Li-O batteries. In this review, we overview the recent advances in understanding the electrochemical and chemical processes that occur during the LiO formation. In the beginning, the oxygen reduction mechanisms, the identification of O/LiO intermediates, and their influence on the LiO morphology have been discussed. The effects of the discharge current density and potential on the LiO growth model have been subsequently reviewed. Special focus is then given to the prominent strategies, including the electrolyte-mediated strategy and the cathode-catalyst-tailoring strategy, for controlling the LiO growth pathways. Finally, we conclude by discussing the profound implications of controlling LiO formation for further development in Li-O batteries.

Li‐dendrite growth and unsatisfactory sulfur cathode performance are two core problems that restrict the practical applications of lithium–sulfur batteries (LSBs). Here, an all‐in‐one design concept for a Janus separator, enabled by the interfacial engineering strategy, is proposed to improve the performance of LSBs. At the interface of the anode/separator, the thin functionalized composite layer contains high‐elastic‐modulus and high‐thermal‐conductivity boron nitride nanosheets and oxygen‐group‐grafted cellulose nanofibers (BNNs@CNFs), by which the formation of “hot spots” can be effectively avoid, the Li‐ion flux homogenized, and dendrite growth suppressed. Meanwhile, at the interface between the separator and the cathode, the homogenously exposed single‐atom Ru on the surface of reduced graphene oxide (rGO@Ru SAs) can “trap” polysulfides and reduce the activation energy to boost their conversion kinetics. Consequently, the LSBs show a high capacity of 460 mAh g–1 at 5C and ultrastable cycling performance with an ultralow capacity decay rate of 0.046% per cycle over 800 cycles. To further demonstrate the practical prospect of the Janus separator, a lithium–sulfur pouch cell using the Janus separator delivers a cell‐level energy density of 310.2 Wh kg–1. This study provides a promising strategy to simultaneously tackle the challenges facing the Li anode and the sulfur cathode in LSBs.

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Plastic products, used in almost all aspects of daily life because of their low cost, durability, and portability, could be broken down into micro- and nano-scale plastics, thereby increasing the...