Bioinspired Structural Composite Flexible Material with High Cushion Performance.

Impacts occur everywhere, and they pose a serious threat to human health and production safety. Flexible materials with efficient cushioning and energy absorption are ideal candidates to provide protection from impacts. Despite the high demand, the cushioning capacity of protective materials is still limited. In this study, an integrated bionic strategy is proposed, and a bioinspired structural composite material with highly cushioning performance is developed on the basis of this strategy. The results demonstrated that the integrated bionic material, an S-spider web-foam, has excellent energy storage and dissipation as well as cushioning performance. Under impact loading, S-spider web-foam can reduce peak impact forces by a factor of 3.5 times better than silicone foam, achieving unprecedented cushioning performance. The results of this study deepen the understanding of flexible cushioning materials and may provide new strategies and inspiration for the preparation of high-performance flexible cushioning materials.

Facile synthesis of multi-phase (Si+SiO2)@C anode materials for lithium-ion batteries.

To bring about a revolution in energy storage through Li-ion batteries, it is crucial to develop a scalable preparation method for Si-based composite anodes. However, the severe volume expansion and poor ionic transport properties of Si-based composites present significant challenges. Previous research focused on SiO and nano Si/C composites to address these issues. In this study, mechanical milling was used to introduce a SiOx layer onto the surface of Si by mixing Si and SiO2 in a 1 : 1 mass ratio. The resulting Si+SiO2 composites (denoted as SS50) exhibited an initial coulombic efficiency (ICE) of 73.5% and high rate performance. To further stabilize the overall structure, kerosene was introduced as a carbon source precursor to generate a coating layer. The resulting multiphase composite structure (SiOx+SiO2+C), designated as SS50-900C, demonstrated a capacity retention of 79.5% over 280 cycles at its capacity of 487 mA h g-1. These results suggest that a cost-effective mechanical ball milling refinement of Si+SiO2 and a gas-phase encapsulation process can significantly improve the electrochemical performance of Si-based composites.

Improvement of stability and capacity of Co-free, Li-rich layered oxide Li1.2Ni0.2Mn0.6O2 cathode material through defect control.

Layered oxides based on manganese (Mn), rich in lithium (Li), and free of cobalt (Co) are the most promising cathode candidates used for lithium-ion batteries due to their high capacity, high voltage and low cost. These types of material can be written as xLi2MnO3·(1 - x) LiTMO2 (TM = Ni,Mn,etc.). Though, Li2MnO3 is known to have poor cycling stability and low capacity, which hinder its industrial application commercially. In this work, Li1.2Ni0.2Mn0.6O2 materials with different amounts of structural defects was successfully synthesized using powder metallurgy followed by different cooling processes in order to improve its electrochemical properties. Microstructural analyses and electrochemical measurements were carried out on the study samples synthesized by a combination of X-ray diffraction, transmission electron microscopy, and cyclic voltammetry. It is found that the disorder of the transition metal layer in Li2MnO3 promotes its electrochemical activity, whereas the Li/Ni antisites of the Li layer maintain the stability of its local structure. The material with optimal amount of structural defects had an initial capacity of 188.2 mAh g-1, while maintaining an excellent specific capacity of 144.2 mAh g-1 after 500 cycles at 1C. In comparison, Li1.2Ni0.2Mn0.6O2 without structural defect only gives a capacity of 40.8 mAh g-1 after cycling. This microstructural control strategy provides a simple and effective route to develop high-performance Co-free, Li-rich Mn-based cathode materials and scale-up manufacturing.

An Adaptive Bioinspired Foot Mechanism Based on Tensegrity Structures.

Traditional robotic feet have received considerable attention for adaptive locomotion on complex terrain. As an alternative, tensegrity structures have the essential characteristics of deformability, adaptability to the environment, and impact resistance. This article proposes ways to solve the problem of adaptive locomotion on complex terrain based on a tensegrity structure and shows that this approach is particularly useful. On the basis of the locomotion mechanism and morphological structure of the human foot, a structural mapping model of a tetrahedral mast tensegrity structure is established through bionic mapping. A model of an adaptive foot mechanism is established through bioinspired design. Theoretical calculations of the behavior of the mechanism are derived, and the spring stiffnesses are matched. A theoretical method based on mechanical kinematics is presented, and a kinematic solution is realized through inverse kinematics. In addition, the locomotion of the mechanism, which is similar to that of the human foot, is simulated using ADAMS, and the effectiveness of the proposed theory and design method is verified by comparing the simulation output with the theoretically calculated results. Finally, a physical prototype manufactured using three-dimensional printing technology is used to experimentally verify the functional characteristics of the terrain-adaptive locomotion of the proposed mechanism. The results show that the proposed adaptive bioinspired foot mechanism exhibits good stability in an unstructured environment and can mimic the adaptive locomotion characteristics of the human foot on complex terrain remarkably well.