Cocoon Silk-Derived, Hierarchically Porous Carbon as Anode for Highly Robust Potassium-Ion Hybrid Capacitors

Potassium-ion hybrid capacitors(KIHCs) have attracted increasing research interest because of the virtues of potassium-ion batteries and supercapacitors.The development of KIHCs is subject to the investigation of applicable K+storage materials which are able to accommodate the relatively large size and high activity of potassium.Here,we report a cocoon silk chemistry strategy to synthesize a hierarchically porous nitrogen-doped carbon(SHPNC).The as-prepared SHPNC with high surface area and rich N-doping not only offers highly efficient channels for the fast transport of electrons and K ions during cycling,but also provides sufficient void space to relieve volume expansion of electrode and improves its stability.Therefore,KIHCs with SHPNC anode and activated carbon cathode afford high energy of 135 Wh kg-1(calculated based on the total mass of anode and cathode),long lifespan,and ultrafast charge/slow discharge performance.This study defines that the KIHCs show great application prospect in the field of high-performance energy storage devices.

Sea Urchin Spines as a Model-System for Permeable,Light-Weight Ceramics with Graceful Failure Behavior.Part Ⅱ.Mechanical Behavior of Sea Urchin Spine Inspired Porous Aluminum Oxide Ceramics under Compression

Sea urchin spines were chosen as a model system for biomimetic ceramics obtained using starch-blended slip casting. Porous alumina ceramics with cap-shaped layers with different alternating porosities were found to have superior fracture behavior under bulk compression compared to ceramics with uniform porosity.They fail in a cascading manner,absorbing high amounts of energy during extended compression paths.The porosity variation in an otherwise single phase material mimicks the architectural microstructure design of sea urchin spines of Heterocentrotus mammillatus,which are promising model materials for impact protection.

Energy Absorption in Functionally Graded Concrete Bioinspired by Sea Urchin Spines

Functionally Graded Concrete （FGC） is fabricated at the Institute for Lightweight Structures and Conceptual Design （ILEK） by using a layer-by-layer technique with two different technological procedures： casting and dry spraying. Functional gradations are developed from two reference mixtures with diametrically opposed characteristics in terms of density, porosity, compression strength and elasticity modulus. In this study the first mixture consists of Normal Density Concrete （NDC）, with density about 2160 kg·m^-3 while the second mixture helps to obtain a very lightweight concrete, with density about 830 kg·m^-3. The FGC specimens have layers with different alternating porosities and provide superior deformability capacity under bulk compression compared to NDC specimens. In addition, the FGC specimens experienced a graceful failure behaviour, absorbing high amounts of energy during extended compression paths. The porosity variation inside the layout of tested specimens is inspired by the internal structure of sea urchin spines of heterocentrotus mammillatus, a promising role model for energy absorption in biomimetic engineering.

Artificial periosteum in bone defect repair--A review

Periosteum is a thin membrane that encases the surfaces of most bones.It is composed of an outer fibrous layer contains longitudinally oriented cells and collagen fibers and an inner cambial layer that consists of multipotent mesenchymal stem cells（MSCs）and osteogenic progenitor cells.Periosteum has a function of regulating cell and collagen arrangement,which is important to the integrity,modelling and remodelling of bone,particularly during bone defect repair.Apart from autograft and allograft,artificial periosteum,or tissue-engineered periosteum mimicking native periosteum in structure or function,made up of small intestinal submucosa,acellular dermis,induced membrane,cell sheets,and polymeric scaffolds,and so on,has been developed to be used in bone defect repair.In this review,we classify the artificial periosteum into three approaches based on the material source,that is,native tissues,scaffoldfree cell sheets and scaffold-cell composites.Mechanisms,methods and efficacy of each approach are provided.Existing obstacles and enabling technologies for future directions are also discussed.