KIST Europe

Inside Front Cover In article number 2500827, Jo and co-workers highlight the critical role of electrolyte composition in modulating the reactivity of crystal water at the Prussian blue (PB) cathode–electrolyte interface in sodium-ion batteries (SIBs). NaTFSI mitigates interfacial degradation by disrupting hydrogen-bond networks and suppressing water-mediated side reactions, whereas NaClO4 intensifies water coordination, inducing cathode-electrolyte interphase instability. These findings provide valuable guidance for optimizing electrolytes in PB-based SIBs.

ABSTRACT The lifespan of Zn‐ion batteries (ZIBs) is severely hindered by dendritic Zn growth and side reactions. These drawbacks are exacerbated under practical conditions, such as high current density. Herein, an adhesive ionic liquid electrolyte additive with a zincophilic side chain is introduced to achieve a stable electrode/electrolyte interface and efficient mass transport via a modulated electrical double layer and zincophilic molecular channels. The additives anchor to the Zn anode, forming a robust molecular layer that modulates local electric field distribution and serves as a tip‐shielding barrier. Ether‐hydroxyl‐functionalized side chains with lone pairs of electrons facilitate selective Zn 2+ ion conduction, promoting Zn‐rich layer formation. Stable battery operation is achieved under fast‐charging conditions along with suppressed dendritic Zn growth and side reactions. Zn//Zn cell with the additives exhibits a long cycle life of 1100 h at 10 mA cm −2 and 10 mAh cm −2 . The superior reversibility is further validated in a practical Zn–I 2 system, demonstrating stable capacity retention over 10 000 cycles and a high reversible capacity of 2.3 mAh cm −2 at a current density of 20 mA cm −2 , outperforming state‐of‐the‐art ZIBs. This study provides novel insights into the design of bifunctional additives and demonstrates a pathway for durable and high‐energy ZIBs.

HighlightsWhat are the main findings?Four f-TNA structural configurations (closed/open, up/down) were compared to optimize DSSC performance.The open f-TNA structure, with the barrier layer removed, showed the highest power conversion efficiency (PCE ≈ 7.73%).The best PCE (7.73%) was achieved using the open-up f-TNA photoanode configuration. Barrier layer removal in f-TNA effectively minimized charge transfer resistances (Rct1 and Rct2).The closed-up configuration yielded the lowest PCE (5.52%) due to poor electrolyte diffusion kinetics.What are the implications of the main findings?The structural configuration and orientation of f-TNA are critical design parameters for high-performance DSSC.Structural optimization alone is a highly effective, additive-free strategy for maxim-izing TiO2 nanotube DSSC efficiency.Opening the f-TNA bottom is essential for enhancing charge collection and improv-ing electrolyte penetration.The study presents fundamental guidelines for engineering f-TNA electrodes in next-generation photoelectrochemical devices.Dye-sensitized solar cells (DSSCs) are known for their excellent low-light performance, cost-effectiveness, and flexibility. The photoanode has a crucial role in enhancing the overall performance of DSSCs and can be modified with different nanostructures. This study explores the impact of photoanode structure on the power conversion efficiency (PCE) of DSSCs, where four configurations of freestanding TiO2 nanotube arrays (f-TNAs), closed-up, closed-down, open-up, and open-down, were employed as photoanodes. Performance was evaluated based on current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and PCE concerning dye adsorption, electrolyte diffusion, electron transport, and barrier layer. DSSCs based on open configurations, open-up and open-down f-TNAs, demonstrated superior performance, achieving PCE of 7.73% and 7.71%, respectively. The primary distinction between the DSSCs based on open-up f-TNAs and those based on open-down f-TNAs lies in the dye adsorption time and electron diffusion characteristics. The PCE for DSSCs with closed-down f-TNAs was measured at 6.78%, while DSSCs with closed-up f-TNAs showed a lower PCE of 5.52%. The presence of a barrier layer under the bottom of f-TNAs impacted the PCE for DSSCs with closed-down f-TNAs, whereas for DSSCs with closed-up f-TNAs, insufficient dye loading, poor electrolyte diffusion and barrier layer reduced the performance.

The online version contains supplementary material available at 10.1007/s43188-025-00316-w.

Drug delivery through the skin using miniaturised needles is a promising microtechnology-based strategy for precise control of drug release dynamics. Active injection of therapeutic insulin through hollow microneedles has recently been implemented as patch-type microsystems in which liquid dispensers and drug reservoirs are integrated with the microneedle array. Nevertheless, little is known about the relationship of the micro-infusion parameters, such as the microfluid flow rate, geometry and opening size of hollow microneedle, and needle insertion depth, to the biomechanics of viable skin multilayers and its associated pain perception, and to insulin absorption kinetics by microcirculation. In this study, we developed a novel computational modelling method that encapsulates numerical analysis modules to simulate (i) insulin infusion processes by intradermal and subcutaneous injection, (ii) skin tissue deformation and pain sensation during micro-infusion, and (iii) microfluid transport and pharmacokinetics. Our model predicts that the convection-diffusion behaviour of the insulin solution in the tissue matrix can be dramatically affected by the different target skin layers, that is, the dermis and hypodermis. Furthermore, this could be extended to the differences in insulin absorption kinetics depending on the skin layer where insulin is injected. We found that coupling between the biomicrofluidics of insulin infusion and the biomechanics of heterogeneous skin tissues could result in a prominent variation in plasma insulin concentration as a function of time. In addition, a numerical relationship between the pain perception level and microflow characteristics at the opening of the needle tip was obtained. Our model could serve as a versatile tool for designing skin drug delivery microdevices, by considering the quantitative interactions of the multifaceted biophysical mechanisms involved in microneedle-based drug infusion.

Snap-through, a rapid transition of a system from an equilibrium state to a nonadjacent equilibrium state, is a valuable design element of soft devices for converting a monolithic stimulus into systematic responses with impulsive motions. A common way to benefit from snap-through is to embody it within structures and materials, such as bistable structures. Torque-reversal mechanisms discovered in nature, which harness snap-through instability via muscular forces, may have comparative advantages. However, the current intricacy of artificial torque-reversal mechanisms, which require sophisticated kinematics/kinetics, constrains design possibilities for soft joints and devices. Here, we harnessed hyperelasticity to implement a torque-reversal mechanism in a soft joint, generating repetitive cilia-like beating motions through an embedded tendon. The developed hyperelastic torque-reversal mechanism (HeTRM) exhibits transient bistability under a specific compressive displacement/force threshold, with snap-through occurring at the point where the transience ends. To validate the effectiveness of this design principle, we explored the functionalities of HeTRM in energy storage and release, dual modes for impulsive and continuous motion, mechanical fuse, and rapid three-dimensional motions, through proof-of-concept soft machines. We expect that this design principle provides insight into incorporating snap-through behavior in soft machines and may aid in understanding the relationship between torque-reversal mechanisms and bistability.

Humans use their dexterous fingers and adaptable palm in various multiobject grasping strategies to efficiently move multiple objects together in various situations. Advanced manipulation skills, such as finger-to-palm translation and palm-to-finger translation, enhance the dexterity in multiobject grasping. These translational movements allow the fingers to transfer the grasped objects to the palm for storage, enabling the fingers to freely perform various pick-and-place tasks while the palm stores multiple objects. However, conventional grippers, although able to handle multiple objects simultaneously, lack this integrated functionality, which combines the palm's storage with the fingers' precise placement. Here, we introduce a gripper for multiobject grasping that applies translational movements of fingertips to leverage the synergistic use of fingers and the palm for enhanced pick-and-place functionality. The proposed gripper consists of four fingers and an adaptive conveyor palm. The fingers sequentially grasp and transfer objects to the palm, where the objects are stored simultaneously, allowing the gripper to move multiple objects at once. Furthermore, by reversing this process, the fingers retrieve the stored objects and place them one by one in the desired position and orientation. A finger design for simple object translating and a palm design for simultaneous object storing were proposed and validated. In addition, the time efficiency and pick-and-place capabilities of the developed gripper were demonstrated. Our work shows the potential of finger translation to enhance functionality and broaden the applicability of multiobject grasping.

The journal retracts the article, "Myogenesis Effects of RGX365 to Improve Skeletal Muscle Atrophy" [...].