Aqueous zinc-metal batteries (AZBs) have become a key research focus for large-scale energy storage, owing to their intrinsic safety, low cost, and environmental friendliness. Although extensive work has addressed anodes, cathodes, separators, and electrolytes, the binder also plays a critical role in electrode fabrication and significantly affects the redox kinetics of AZB electrodes. However, binders have received limited attention in this field, and no systematic review has yet summarized binder design specifically for aqueous batteries. This review comprehensively covers recent advances in AZB binders, categorizes their functional mechanisms and optimization strategies, and offers perspectives on remaining challenges to guide the rational design of high-performance binders.
Increasing the contraction force of vacuum artificial muscles (VAMs) without enlarging their cross-sectional area remains challenging. Here, we demonstrate that increasing the cross-sectional perimeter enhances contraction force at a fixed area. A quasistatic output force model based on virtual work was developed and experimentally validated using circular, regular hexagonal, regular pentagonal, square, and equilateral triangular VAMs of equal cross-sectional area. The model and experiments yielded the same force ranking: triangular, square, pentagonal, hexagonal, and circular, which was consistent with the ranking of their cross-sectional perimeters. After subtracting the common pressure force, the axial force generated by side-skin tension per unit effective perimeter was nearly identical across the five VAMs, indicating approximate proportionality between this force and effective perimeter. Based on this relationship, bioinspired multicell VAMs were developed to increase the total effective perimeter without increasing the total area. A six-cell VAM composed of triangular cells generated twice the contraction force of an equal-area single-cell hexagonal VAM. This advantage persisted as the axial gap between adjacent internal frames varied, showing that the perimeter-based force-enhancement rule is not limited to a specific axial structural configuration. These results establish a simple, general geometric rule for enhancing VAM contraction force without increasing cross-sectional area.
Space-based gravitational wave (GW) detection offers a powerful platform for observing millihertz GW signals and probing extreme astrophysical phenomena. As an important part for GW detection, monitoring key state during test-mass (TM) capture, positioning, and release is essential. Here, we designed a capture, positioning, and release mechanism (CPRM) for TianQin project, and further constructed a monitoring system based on triboelectric nanogenerator (TENG) to achieve state recognition of TM during the three-stage process. Three nano-TENG sensors generate characteristic pulse signals (>0.5 V, >0.8 V, >2.5 V, respectively). Varied timing sequences and peak magnitudes of the signals characterize the mechanical motions of the CPRM, allowing effective feedback and state recognition throughout the multistage capture, positioning and release (CPR) process. This work provides a promising strategy for monitoring the TM states during the CPR process and broadens the application of TENGs in high-precision aerospace systems.
4D-printed mechanical metamaterials combine stimuli-responsive materials with architected mechanical designs, enabling printed structures to change shape, stiffness, deformation mode, or function after fabrication. This review discusses these systems as responsive architectures in which material response and geometry-driven mechanics are jointly designed. We summarize representative material platforms, external stimuli, and additive manufacturing routes, including shape-memory polymers, hydrogels, liquid crystal elastomers, conductive composites, field-responsive systems, and multimaterial hybrids. We then discuss structural design based on geometry, stiffness contrast, gradients, multistability, and topological transformation, along with the modeling and inverse-design methods used to support these designs. Representative applications are reviewed in programmable reconfiguration, wave and vibration control, recoverable energy absorption, sensing-integrated systems, intelligent regulation, and biomedical devices. Finally, remaining challenges are discussed, including slow actuation, fatigue resistance, multimaterial interface stability, quantitative programming, scalable fabrication, and standardized evaluation. These issues will shape the development of reliable adaptive mechanical systems.
This study presents a data-driven framework for the design, prediction, and optimization of electrothermally actuated composite structures based on continuous carbon-fiber reinforced shape memory polymers (CCF-SMPs). A Multiphysics model was developed and calibrated against experimental thermal-field, unfolding-trajectory, and recovery-force measurements. The resulting simulation-experiment dataset was then used to train and evaluate a surrogate model. Continuous fibers contributed to improved thermal uniformity, reduced activation gradients, and increased recovery force relative to pure SMP through a coupled electro-thermo-mechanical effect, rather than through thermal conductivity alone. A surrogate model trained on hybrid experimental-simulation datasets was developed to predict key outputs, including temperature evolution, unfolding angle, recovery force, and energy consumption, and was evaluated against independent experimental measurements. The framework was further validated on architected composite actuator units with varied fiber orientations and hinge geometries. AI-predicted force-displacement responses showed less than 7% stiffness error and less than 5% peak-force error relative to experiments. Finally, the optimizer was applied to variable-thickness morphing structures, achieving a 35% reduction in actuation time, a 28% improvement in geometric accuracy, and a 22% reduction in energy consumption. These results demonstrate the potential of AI-guided design for next-generation high-performance morphing composite systems.
