Transition-metal disulfide with its layered structure is regarded as a kind of promising host material for sodium insertion, and intensely investigated for sodium-ion batteries. In this work, a simple solvothermal method to synthesize a series of MoS nanosheets@nitrogen-doped graphene composites is developed. This newly designed recipe of raw materials and solvents leads the success of tuning size, number of layers, and interplanar spacing of the as-prepared MoS nanosheets. Under cut-off voltage and based on an intercalation mechanism, the ultrasmall MoS nanosheets@nitrogen-doped graphene composite exhibits more preferable cycling and rate performance compared to few-/dozens-layered MoS nanosheets@nitrogen-doped graphene, as well as many other reported insertion-type anode materials. Last, detailed kinetics analysis and density functional theory calculation are also employed to explain the Na - storage behavior, thus proving the significance in surface-controlled pseudocapacitance contribution at the high rate. Furthermore, this work offers some meaningful preparation and investigation experiences for designing electrode materials for commercial sodium-ion batteries with favorable performance.

Layered γ‐type iron oxyhydroxide (γ‐FeOOH) is a promising material for various applications; however, its sheet‐shaped structure often suffers from instability that results in aggregation and leads to inferior performance. Herein, a kinetically controlled hydrolysis strategy is proposed for the scalable synthesis of γ‐FeOOH nanosheets arrays (NAs) with enhanced structural stability on diverse substrates at ambient conditions. The underlying mechanisms for the growth of γ‐FeOOH NAs associated with their structural evolution are systematically elucidated by alkalinity‐controlled synthesis and time‐dependent experiments. As a proof‐of‐concept application, γ‐FeOOH NAs are developed as electrocatalysts for the oxygen evolution reaction (OER), where the sample grown on nickel foam (NF) exhibits superior performance of high catalytic current density, small Tafel slope, and exceptional durability, which is among the top level of FeOOH‐based electrocatalysts. Density functional theory calculations suggest that γ‐NiOOH in situ generated from the electrooxidation of NF would induce charge accumulation on the Fe sites of γ‐FeOOH NAs, leading to enhanced OER intermediates adsorption for water splitting. This work affords a new technique to rationally design and synthesize γ‐FeOOH NAs for various applications.

Li‐chalcogen batteries, especially the Li–S batteries (LSBs), have received paramount interests as next generation energy storage techniques because of their high theoretical energy densities. However, the associated challenges need to be overcome prior to their commercialization. Elemental selenium, another chalcogen member, would be an attractive alternative to sulfur owing to its higher electronic conductivity, comparable capacity density, and moreover, excellent compatibility with carbonate electrolytes. Unlike LSBs, the research and development of Li–Se batteries (LSeBs) have garnered burgeoning attention but are still in their infant stage, where a comprehensive yet in‐depth overview is highly imperative to guide future research. Herein, a critical review of LSeBs, in terms of the underlying mechanisms, cathode design, blocking layer engineering, and emerging solid‐state electrolytes is provided. First, the electrolyte‐dependent electrochemistry of LSeBs is discussed. Second, the advances in Se‐based cathodes are comprehensively summarized, especially highlighting the state‐of‐the‐art SexSy cathodes, and mainly focusing on their structures, compositions, and synthetic strategies. Third, the versatile separators/interlayers optimization and interface regulation are outlined, with a particular focus on the emerging solid‐state electrolytes for advanced LSeBs. Last, the remaining challenges and research orientations in this booming field are proposed, which are expected to motivate more insightful works.

CoP nanotubes were fabricated by phosphidation of Co salt inside an anodic aluminum oxide template as an efficient hydrogen-evolving electrocatalysts.