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[This corrects the article DOI: 10.1016/j.bioactmat.2020.08.035.].
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Fast-charging sodium ion batteries remain deeply challenged by the lack of suitable carbonaceous anodes that exhibit intercalation plateau with fast kinetics. Here we develop a few-layer graphitic carbon with nanoscale architecture, which enables shortened Na+ ion diffusion path and fast formation of fully intercalated phase at the same time. Combined in situ Raman and electrochemical test reveal that this graphitic carbon with highly crystalline few layers follows surface-controlled intercalation rather than typical diffusion-controlled kinetics observed in natural graphite. As a result, a few-layer graphitic carbon anode maintains the reversible capacity of 106 mAh g-1 at 10 A g-1 and achieves 87% capacity retention even after 10â¯000 cycles at 1 A g-1. This work provides new insight on the Na storage mechanism in fast-charging graphitic carbon as well as the design of carbon anodes for high-rate sodium ion batteries.
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Prussian blue (PB) is a very promising cathode for K-ion batteries but its low electronic conductivity and deficiencies in the framework aggravate electrochemical performances. Compositing with conductive reduced graphene oxide (rGO) is an effective solution to address this problem. Nevertheless, little attention was paid to the loss of oxygen-containing functional groups on the rGO substrate during the compositing process, which weakens the interaction between PB and rGO and leads to poor electrochemical performance of PB/rGO. Herein, this interaction effect associated with surface functional groups is first openly debated. Two commonly used carbon substrates, graphene oxide (GO) and rGO, are investigated. A more stable interaction between PB and GO contributes to a higher capacity retention (91.8%) than that of PB/rGO (69.7%) after 300 cycles at a current density of 5 C. Meanwhile, polyvinylpyrrolidone (PVP) is employed to repair the weak interaction between PB and rGO substrates. PB is anchored to the rGO surface through the stable covalent linking of amide groups in PVP. A superior rate capability of 72 mA h g-1 at 10 C and an improved capacity retention of 96.5% over 800 cycles at 5 C are obtained by as-prepared PB/PVP-rGO. This study provides a deeper understanding of fabricating PB/carbon composites with a robust connection.
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Peri-implant aseptic inflammation and osteolysis can cause aseptic loosening, leading to the failure of implants. Therefore, aseptic loosening of orthopedic implants remains an imminent problem for the development of durable and effective implants. In this work, a common anti-inflammatory drug (aspirin, ASA) was loaded in poly(lactic-co-glycolic acid) (PLGA) to construct nanofiber coatings on titanium (Ti) via electrospinning. The adhesion of the nanofiber coatings to Ti was ensured by polydopamine (PDA) modification. A stable and sustainable release of aspirin from the nanofiber coatings could last up to 60 days. Such electrospun PLGA@ASA nanofiber coatings could promote proliferation and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) as well as inhibit M1 polarization and RANKL-induced osteoclast differentiation of macrophages in vitro. These results indicated that this facile formulation of the PLGA@ASA nanofiber coatings for long-term drug release could be expected to address the problem of aseptic loosening effectively in dual directions of both anti-inflammation and improving osseointegration simultaneously. Notably, the in vivo experiments demonstrated that PLGA@ASA nanofiber coatings did promote osseointegration ability of Ti implants significantly, even in challenging condition with wear particles, and also effectively inhibited Ti particle induced osteolysis around the implants. This work indicates a promising way for the development of durable and effective implants by using PLGA@ASA-PDA-Ti to address the problem of aseptic loosening in dual directions.
