Li‐metal is gaining attention as a next generation anode active material, of which the primary attribute is its energy density. However, Li dendrite formation is the primary challenge. Herein, a design strategy with increased structural dimensions and hierarchy for Li‐metal anode is investigated to stabilize the dendrite formation for extending the cycle life with high reversibility. For this, diverse structural current collectors (CCs) are fabricated by manipulating structural design in different length scales and characterized as a Li‐metal anode. The hierarchy (i.e., nanostructures inside the microcavities) can not only reduce the current density on entire anode surface but also concentrate the local electrical field onto inner surfaces of the microstructures, inducing preferential Li nucleation inside microcavities and promoting confined growth of Li. It is confirmed that introduction of structural hierarchy can enhance the cycle life by 364% and the preservation of coulombic efficiency > 90% by 266%. The design strategy is extended by exploring a practical one‐step fabrication of the hierarchical CC with even greater performance via the inward growth mechanism. This work elucidates the mechanism of inward Li growth using tailored surface geometries for Li dendrite suppression, which can be a guideline for designing structured anode CCs for Li‐metal batteries.

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Porous carbon nanoframeworks have attracted considerable interest for promising applications such as water purification, catalyst supports, gas adsorption, and energy storage owing to their high surface area and electrical conductivity. Traditional synthetic methods applied for porous carbon commonly involve a number of toxic organic solvents and post‐treatments, which are time‐consuming and energy inefficient. Herein, the authors report a facile synthetic method for generating atomically small pores in carbon nanofibers, with sizes varying from ≈0.55 nm to a few nanometers, using water‐soluble and cost‐effective polyvinyl alcohol (PVA) nanofibers as a precursor through the introduction of an iodine treatment. In particular, the generation mechanism of ultrafine pores during the carbonization of iodinated PVA are deeply analyzed and elucidated through meticulous investigations into their chemical/structural properties. By the suggested mechanism, the specific surface area of the generated pores is found to be extensively controlled from 100–650 m2 g−1. This phenomenon is advanced to produce well‐controlled hierarchically porous carbon nanofibers, and analyzes the corresponding electrochemical characteristics to explore the potential usage of such fibers as a supercapacitor.

Si has attracted considerable interest as a promising anode material for nextgeneration Li-ion batteries owing to its outstanding specific capacity. However, the commercialization of Si anodes has been consistently limited by severe instabilities originating from their significant volume change (approximately 300%) during the charge− discharge process. Herein, we introduce an ultrafast processing strategy of controlled multipulse flash irradiation for stabilizing the Si anode by modifying its physical properties in a spatially stratified manner. We first provide a comprehensive characterization of the interactions between the anode materials and the flash irradiation, such as the condensation and carbonization of binders, sintering, and surface oxidation of the Si particles under various irradiation conditions (e.g., flash intensity and irradiation period). Then, we suggest an effective route for achieving superior physical properties for Si anodes, such as robust mechanical stability, high electrical conductivity, and fast electrolyte absorption, via precise adjustment of the flash irradiation. Finally, we demonstrate flash-irradiated Si anodes that exhibit improved cycling stability and rate capability without requiring costly synthetic functional binders or delicately designed nanomaterials. This work proposes a cost-effective technique for enhancing the performance of battery electrodes by substituting conventional long-term thermal treatment with ultrafast flash irradiation.

Air filters have evolved to satisfy demand for higher air quality in various industries over the decades. The common meltblown polymeric filters have a short lifetime due to charge loss,...