Lithium−sulfur (Li−S) batteries are attractive candidates for next-generation rechargeable batteries. With the steady development of sulfur cathodes, the recent revival of research on dendrite-free Li metal anodes offers opportunities to improve the stabilities and safety of Li−S batteries. However, the low capacities and low Li utilizations of current Li anodes hinder the improvement of the energy densities of Li−S batteries. Here, we present a facile approach to fabricate lithiophilic three-dimensional porous current collectors by modifying commercial metal foams with yolk−shell structured N-doped porous carbon nanosheets. Benefiting from the structure-based rational design, this current collector is able to generate dendrite-free Li anodes with improved Coulombic efficiencies and life spans, enabling carbon/sulfur cathodes to exhibit significantly enhanced stabilities (e.g., 78.1% of capacity retention after 1400 cycles). More importantly, we successfully constructed a high-areal-capacity Li−S full cell (9.84 mAh cm −2 ) with 82% Li utilization. This work provides a promising route toward high-energy-density Li−S batteries.

Metallic lithium has long been deemed as the ultimate anode material for future high‐energy‐density Li batteries. However, the commercialization of Li metal anodes remains hindered by some major hurdles including their huge volume fluctuation during cycling, unstable solid electrolyte interface (SEI), and dendritic deposition. Herein, the concept of nano‐encapsulating electrode materials is attempted to tackle these problems. Nitrogen‐doped hollow porous carbon spheres (N‐HPCSs), prepared via a facile and low‐cost method, serve as the nanocapsules. Each N‐HPCS has a lithophilic carbon shell with a thin N‐rich denser layer on its inner surface, which enables preferential nucleation of Li inside the hollow sphere. It is demonstrated by in situ electron microscopy that these N‐HPCS hosts allow Li to be encapsulated in a highly reversible and repeatable manner. Ultralong Li filling/stripping cycling inside single N‐HPCSs is achieved, up to 50 cycles for the first time. Li ion transport across multiple connected N‐HPCSs, leading to long‐range Li deposition inside their cavities, is visualized. In comparison, other types of carbon spheres with modified shell structures fail in encapsulating Li and dendrite suppression. The necessity of the specific shell design is therefore confirmed for stable Li encapsulation, which is essential for the N‐HPCS‐based anodes to achieve superior cycling performance.

Metallic bismuth has drawn attention as apromising alloying anode for advanced potassium ion batteries (PIBs). However,s erious volume expansion/electrode pulverization and sluggish kinetics always lead to its inferior cycling and rate properties for practical applications.T herefore,a dvanced Bibased anodes via structural/compositional optimization and sur-/interface design are needed. Herein, we develop abottomup avenue to fabricate nanoscale Bi encapsulated in a3 DNdoped carbon nanocages (Bi@N-CNCs) framework with av oid space by using an ovel Bi-based metal-organic framework as the precursor.W ith elaborate regulation in annealing temperatures,t he optimizedB i@N-CNCs electrode exhibits large reversible capacities and long-duration cyclic stability at high rates when evaluated as competitive anodes for PIBs. Insights into the intrinsic K +-storage processes of the Bi@N-CNCs anode are put forward from comprehensive in situ characterizations.

Antimony trisulfide-based materials have drawn growing attention as promising anode candidates for potassium-ion batteries (PIBs) because of their high capacity and good working potential. Despite the extensive investigations on their electrochemical properties, the fundamental reaction mechanisms of Sb 2 S 3 anodes, especially the reaction kinetics, structural changes, and phase evolutions, remain controversial or even largely unknown. Here, using in situ transmission electron microscopy, the entire potassiationdepotassiation cycles of carbon-coated Sb 2 S 3 single-crystal nanowires are tracked in real time at the atomic scale. The potassiation of Sb 2 S 3 involves multistep reactions including intercalation, conversion, and two-step alloying, and the final products are identified as cubic K 2 S and hexagonal K 3 Sb. These findings are confirmed by density functional theory calculations. Interestingly, a rocket-launching-like nanoparticle growth behavior is observed during alloying reactions, which is driven by the K + concentration gradient and release of stress. More impressively, the potassiated products (i.e., K 3 Sb and K 2 S) can transform into the original Sb 2 S 3 phase during depotassiation, indicating a reversible phase transformation process, as distinct from other metal chalcogenide based electrodes. This work reveals the detailed potassiation/depotassiation mechanisms of Sb 2 S 3-based anodes and can facilitate the analysis of the mechanisms of other metal chalcogenide anodes in PIBs.

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