Long-term stability and high-rate capability have been the major challenges of sodium-ion batteries. Layered electroactive materials with mechanically robust, chemically stable, electrically and ironically conductive networks can effectively address these issues. Herein we have successfully directed carbon nanofibers to vertically penetrate through graphene sheets, constructing robust carbon nanofiber interpenetrated graphene architecture. Molybdenum disulfide nanoflakes are then grown in situ alongside the entire framework, yielding molybdenum disulfide@carbon nanofiber interpenetrated graphene structure. In such a design, carbon nanofibers prevent the restacking of graphene sheets and provide ample space between graphene sheets, enabling a strong structure that maintains exceptional mechanical integrity and excellent electrical conductivity. The as-prepared sodium ion battery delivers outstanding electrochemical performance and ultrahigh stability, achieving a remarkable specific capacity of 598 mAh g −1 , long-term cycling stability up to 1000 cycles, and an excellent rate performance even at a high current density up to 10 A g −1 .

Bilayered porous scaffolds have recently attracted interest because of their considerable promise for repairing osteochondral defects. However, determination of optimal pore size in bilayered porous scaffolds remains an important issue. This study investigated the in vivo effects of pore size in bilayered scaffolds using a rabbit model of osteochondral defects. We fabricated five types of integrated bilayered poly(lactide-co-glycolide) (PLGA) scaffolds with different pore sizes in the chondral and osseous layers (50-100 µm, 100-200 µm, 200-300 µm, and 300-450 µm). A subset of bilayered scaffolds seeded with or without allogenic bone marrow mesenchymal stem cells (BMSCs) was implanted in rabbit osteochondral defects. All of the cell/scaffold composite constructs supported the simultaneous regeneration of articular cartilage and subchondral bone, but the best results were observed in cell-seeded PLGA scaffolds with 100-200 µm pores in the chondral layer and 300-450 µm pores in the osseous layer. Our study supports the concept that the effects of pore size on osteochondral repair should be taken into consideration during scaffold design for tissue engineering.

The ability to restrict the shuttle of lithium polysulfide (LiPS n ) and improve the utilization efficiency of sulfur represents an important endeavor toward practical application of lithium−sulfur (Li−S) batteries. Herein, we report the crafting of a robust 3D graphene-wrapped, nitrogen-doped, highly mesoporous carbon/sulfur (G-NHMC/S) hierarchical aerogel as an effective polysulfide confinement matrix for a highly stable Li−S battery. Rich polar sites of NHMC firmly anchor LiPS n on the matrix surface. Porous NHMC provides ample space for accommodating sulfur and cushioning its volume expansion. Moreover, graphene wrapped on NHMC/S not only physically hinders the LiPS n shuttle but also interconnects the isolated NHMC/S, thus increasing electron transfer rate. Taken together, triple confinement of G-NHMC/S aerogel synergistically retains the soluble LiPS n and displays a specific capacity of 1322 mAh g −1 and 1000-cycle life. As such, rationally designed 3D carbon/sulfur aerogel affords a unique platform to impart high energy density and stable electrodes for energy storage devices.

Single-atom and double-atom catalysts have emerged as new frontiers in many fields due to their high atom-utilization efficiency, excellent catalytic properties and good durability. In this decade, Fe-based atomic catalysts...

This study is aimed at investigation of the osteochondral regeneration potential of bilayered PLGA/PLGA-HAp composite scaffolds with one layer made of biodegradable polymer poly(D,L-lactide-co-glycolide) (PLGA) and another layer made of PLGA polymeric matrix coated by bioactive ceramics hydroxyapatite (HAp). The composite scaffolds were fabricated by compression molding/particle leaching and plasma-treated surface deposition. The pore morphology, mechanical properties, and surface deposition of the scaffold were characterized, and the growth of bone marrow derived mesenchymal stem cells or medicinal signaling cells (MSCs) in the scaffold was verified. Thereafter, rabbit models with an artificial osteochondral defect in joint were randomized into three treatment groups: virgin bilayered scaffold, bilayered scaffold preseeded in vitro with MSCs, and untreated blank control. At 16-week postoperation, both the virgin scaffolds and cell-seeded bilayered scaffolds exhibited osteochondral repair, as verified by biomechanics analysis, histological evaluations, and Western blot. The results highlighted the potentiality of the bilayered PLGA/PLGA-HAp composite scaffold for osteochondral tissue engineering, and in particular tissue regeneration or in situ tissue induction, probably by recruiting the local cells toward chondrogenic and osteogenic differentiation in the porous biomaterials.