P-doped CoSe_(2)nanoparticles embedded in 3D honeycomb-like carbon network for long cycle-life Na-ion batteries

We report for the first time a Na-ion battery anode material composed of P-doped CoSe_(2)nanoparticles(P-CoSe_(2))with the size of 5–20 nm that are uniformly embed in a 3 D porous honeycomb-like carbon network.High rate capability and cycling stability are achieved simultaneously.The honeycomb-like carbon network is rationally designed to support high electrical conductivity,rapid Na-ion diffusion as well as the accommodation of the volume expansion from the active P-CoSe_(2)nanoparticles.In particular,heteroatom P-doping within CoSe_(2)introduces stronger P-Co bonds and additional P-Se bonds that significantly improve the structure stability of P-CoSe_(2)for highly stable sodiation/desodiation over long-term cycling.P-doping also improves the electrical conductivity of the CoSe_(2)nanoparticles,leading to highly elevated electrochemical kinetics to deliver high specific capacities at high current densities.Benefiting from the unique nanostructure and atomic-level P-doping,the P-CoSe_(2)(2:1)/C anode delivers an excellent cycle stability with a specific capacity of 206.9 mA h g^(-1)achieved at 2000 mA g^(-1)after 1000 cycles.In addition,this material can be synthesized using a facile pyrolysis and selenization/phosphorization approach.This study provides new opportunities of heteroatom doping as an effective method to improve the cycling stability of Na-ion anode materials.

Phosphorus-doped iron-nitrogen-carbon catalyst with pentacoordinated single atom sites for efficient oxygen reduction

Single-atomic Fe-N4 is the well-acknowledged active site in iron-nitrogen-carbon(Fe-N-C)material for oxygen reduction reaction(ORR).The adjusting of the electronic distribution of Fe-N4 is promising for further enhancing the performance of the Fe-N-C catalyst.Herein,a phosphorus(P)-doped Fe-N-C catalyst with penta-coordinated single atom sites(FeNPC)is reported for efficient oxygen reduction.Fe K-edge X-ray absorption spectroscopy(XAS)verifies the coordination environment of single Fe atom,while density functional theory(DFT)calculations reveal that the penta-coordination and neighboring doped P atoms can simultaneously change the electronic distribution of Fe-N_(4)and its adsorption strength of key intermediates,reducing the reactionfree energy of the potential-limiting step.Electrochemical tests validate the remarkable intrinsic ORR activity of FeNPC in alkaline media(a half-wave potential(E_(1/2))of 0.904 V vs.reversible hydrogen electrode(RHE)and limited current density(JL)of 6.23 mA·cm^(−2))and an enhanced ORR performance in neutral(E_(1/2)=0.751 V,J_(L)=5.27 mA·cm^(−2))and acidic media(E_(1/2)=0.735 V,JL=5.82 mA·cm^(−2))with excellent stability,highlighting the benefits of optimizing the local environment of singleatomic Fe-N4.

Mechanisms of hydrocephalus after intraventricular haemorrhage in adults

Intraventricular haemorrhage(IVH)is defined as the eruption of blood in the cerebroventricular system and occurs mostly secondary to intracerebral haemorrhage(ICH)in adults.Hydrocephalus is a severe complication of IVH that can serve as an independent predictor of increased mortality.In this mini-review,we focus on the mechanisms of hydrocephalus after adult IVH,including blood-clot blockage,barrier impairment,inflammation and blood components,and attempt to reconcile the current research findings into a unified framework.We expect our theoretical framework to help guide future clinical and basic research leading to improved monitoring and intervention for IVH and subsequent hydrocephalus.