Jong Hwan Park

Herein, we report a paradigm-shifting binder-free cathode architecture governed by a spider web-like supramolecular single-walled carbon nanotube (supra-SWCNT) network, bypassing the intrinsic resistive and chemical bottlenecks of conventional polymer binders. By functionalizing SWCNTs with supramolecular 2-ureido-4[1H]pyrimidinone moieties, we achieve exceptional dispersant-free colloidal stability in N-methyl-2-pyrrolidone while simultaneously steering macro-scale electrode structure. Cross-sectional and morphological investigations reveal that these engineered supra-SWCNTs construct an unbroken, interconnected 3D conducting scaffold that completely encapsulates NCM811 microspheres across both intra- and inter-particle domains. Notably, this sophisticated architecture unlocks an unprecedented kinetic self-optimization phenomenon during cycling; electrochemical titration and impedance spectroscopy demonstrate a dramatic twofold increase in the lithium-ion diffusion coefficient paired with a critical reduction in charge-transfer resistance after initial activation. Density functional theory calculations and molecular dynamics simulations further confirmed that supra-SWCNTs promote the formation of a highly uniform, inorganic-rich (LiF-dominant) cathode electrolyte interphase. This synergistic integration of a binder-free matrix and an optimized interface results in superior cycle stability at 1C (94.3% capacity retention after 100 cycles) and enhanced structural integrity, providing a scalable and effective strategy for electrode engineering. Our findings demonstrate that supramolecular control over the electronic and chemical environment of the electrode-electrolyte interface can circumvent the limitations of conventional binder-based electrodes, offering a sophisticated molecular pathway for next-generation, high-performance energy storage.

Sodium metal batteries offer high energy densities but suffer from dendrite formation, which causes capacity loss and short circuits. The present study achieves horizontal sodium growth and stripping by employing a periodic pattern of pyrolytic carbon pillars with vertical facets coated with gold on a copper current collector. The sodiophilic gold layer reduces the energy barrier for sodium nucleation, thereby facilitating preferential sodium nucleation. The regularly spaced carbon pillars with gold-coated sidewalls act as nucleation sites, directing sodium to deposit laterally while maintaining a predominantly horizontal trajectory. Alloys of sodium and gold on the pillar sidewalls induce horizontal expansion of sodium fronts that merge with those from neighboring pillars. During stripping, sodium progressively retracts toward the pillars from these merged boundaries. Electrochemical sodiation and desodiation behaviors in the coexistence of carbon, gold, and copper, influencing subsequent sodium plating, were elucidated by cyclic voltammetry. Copper current collectors with 10-20 μm-high, gold-coated carbon pillars achieved stable half-cell cycling for 1000 cycles at 5 mA cm^-2. The horizontal sodium growth and stripping enabled the high-power and safe operation of anode-free sodium metal full-cells at ultrahigh critical current densities (>3.0 mA cm^-2).

Hydrogen-bond-driven 1D assembly of carbon nanotubes dispersed in organic solvents remains challenging owing to difficulties associated with achieving high oxidation levels and uniform dispersion. Here, we introduced a bioinspired wet-spinning method that utilizes highly oxidized single-walled carbon nanotubes dispersed in organic solvents without superacid or dispersants. By incorporating submicrometer-sized graphene oxide nanosheets, we facilitated the ejection of 1.5 wt % spinning dopes, which formed an interconnected network via hydrogen bonding during coagulation. In this process, swollen carbon nanotube fibers from a multihole spinneret were merged into a single filament via interdigitation, similar to the process observed in spider silk spinning. The resulting interdigitated and conducting carbon nanotube fibers with hierarchical structures serve as versatile textile electrodes in applications such as sensitive textile gas sensors and excellent textile supercapacitors, exhibiting a capacitance of 320 F g^-1 at an extremely high current density of 32 A g^-1. We establish a robust platform for textile electronics, highlighting the significant potential of our bioinspired approach.

The conventional carbonization process for synthesizing hard carbons (HCs) requires high‐temperature furnace operations exceeding 1000 °C, leading to excessive energy consumption and lengthy processing times, which necessitates the exploration of more efficient synthesis methods. This study demonstrates the rapid preparation of HC anodes using intense pulsed light (IPL)‐assisted photothermal carbonization without the prolonged and complex operations typical of traditional carbonization methods. A composite film of microcrystalline cellulose (MCC) and single‐walled carbon nanotubes (SWCNTs) is carbonized at high temperatures in less than 1 min. The SWCNTs efficiently absorbed light energy, enabling ultrafast heating and eliminating the need for prolonged, high‐energy furnace‐based processes. The IPL‐assisted HC anodes exhibited excellent electrochemical performance, with an initial desodiation capacity of 260.4 mAh g⁻¹_anode and 97.5% capacity retention after 200 cycles. These results are comparable to those achieved using traditional furnace‐based carbonization processes, such as carbonizing HC anodes at 1200 °C, validating the effectiveness of IPL‐assisted processes. Additionally, surface and structural analyses revealed the development of pseudo‐graphitic domains, crucial for enhanced sodium‐ion storage. This research highlights IPL‐assisted photothermal carbonization as a viable, time‐efficient, and energy‐saving alternative to conventional methods, offering a sustainable pathway for the large‐scale production of HC anodes for future sodium‐ion battery technologies.

The efficient dispersion of single-walled carbon nanotubes (SWCNTs) has been the subject of extensive research over the past decade. Despite these efforts, achieving individually dispersed SWCNTs at high concentrations remains challenging. In this study, we address the limitations associated with conventional methods, such as defect formation, excessive surfactant use, and the use of corrosive solvents. Our novel dispersion method utilizes the spontaneous charging of SWCNTs in a solvated electron system created by dissolving potassium in hexamethyl phosphoramide (HMPA). The resulting charged SWCNTs (c-SWCNTs) can be directly dispersed in the charging medium using only magnetic stirring, leading to defect-free c-SWCNT dispersions with high concentrations of up to 20 mg/mL. The successful dispersion of individual c-SWCNT strands is confirmed by their liquid-crystalline behavior. Importantly, the dispersion medium for c-SWCNTs exhibits no reactivity with metals, polymers, or other organic solvents. This versatility enables a wide range of applications, including electrically conductive free-standing films produced via conventional blade coating, wet-spun fibers, membrane electrodes, thermal composites, and core-shell hybrid microparticles.

Safe and high‐energy‐density solid‐state batteries (SSBs) are promising candidates for use as the primary power source of next‐generation electric vehicles. However, their poor rate capabilities and long‐term cyclabilities because of material and interfacial instabilities have hindered their widespread commercialization. This study reviewed the recent progress of laser‐assisted interfacial engineering technologies to address the stability issues at the interfaces of SSBs. First, the overview of the interfacial issues of SSBs is briefly outlined. Subsequently, the recent achievements are summarized according to the photophysical mechanisms of laser processing and the type of interfaces to which they are applied. Consequently, the critical laser processing factors to improve the interfacial stabilities of SSBs are highlighted in detail. Finally, the future challenges and opportunities in laser‐assisted interfacial engineering for manufacturing high‐performance SSBs have been discussed to provide guidelines for developing reliable and scalable processes.