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Abstract Fe‐based Prussian blue (Fe‐PB) cathode material shows great application potential in sodium (Na)‐ion batteries due to its high theoretical capacity, long cycle life, low cost, and simple preparation process. However, the crystalline water and vacancies of Fe‐PB lattice, the low electrical conductivity, and the dissolution of metal ions lead to limited capacity and poor cycling stability. In this work, a perylene tetracarboxylic dianhydride amine (PTCDA) coating layer is successfully fabricated on the surface of Fe‐PB by a liquid‐phase method. The aminated PTCDA (PTCA) coating not only increases the specific surface area and electronic conductivity but also effectively reduces the crystalline water and vacancies, which avoids the erosion of Fe‐PB by electrolyte. Consequently, the PTCA layer reduces the charge transfer resistance, enhances the Na‐ion diffusion coefficient, and improves the structure stability. The PTCA‐coated Fe‐PB exhibits superior Na storage performance with a first discharge capacity of 145.2 mAh g−1 at 100 mA g−1. Long cycling tests exhibit minimal capacity decay of 0.027% per cycle over 1000 cycles at 1 A g−1. Therefore, this PTCA coating strategy has shown promising competence in enhancing the electrochemical performance of Fe‐PB, which can potentially serve as a universal electrode coating strategy for Na‐ion batteries.

Abstract Prussian blue analogue Na2Ni[Fe(CN)6] (Ni–PB) has been widely studied as a cathode material for sodium‐ion battery due to its excellent cycling performance. However, Ni–PB has a low theoretical capacity of 85 mAh g−1 because of the electrochemical inertness of Ni. Herein, ternary Ni–PB is successfully synthesized by double doping with Co and Fe at Ni‐site, and the effect of doping with Co and Fe on the electrochemical performance of Ni–PB is systematically investigated through theoretical calculations and electrochemical tests. The first principles calculations confirm that double doping with Co and Fe can significantly reduce the energy barrier and bandgap of Ni–PB. X‐ray diffraction and composition analysis results indicate that ternary NiCoFe–PB composite not only has good crystallinity and high Na content but also has low defects and crystal water. Electrochemical tests reveal that, besides the capacity contribution of high‐spin Co/Fe and low‐spin Fe, Co‐doping enhances the electrochemical activity of low‐spin Fe and Fe‐doping improves the activity of high‐spin Co; moreover, double doping can decrease the diffusion resistance of Na+ ions through solid electrolyte interface film, accelerate the kinetics for both ion diffusion process and Faradic reaction, and increase active sites. Under the synergistic effect of Co and Fe, this ternary NiCoFe–PB exhibits outstanding electrochemical performance with a high initial discharge capacity of 120.4 mAh g−1 at 20 mA g−1 and an extremely low capacity fading rate of 0.0044% per cycle at a high current density of 2 A g−1 even after 10,000 cycles, showing great application potential of ternary NiCoFe–PB in the field of large‐scale energy storage.

Abstract Background Traumatic avulsion injuries to the anus, although uncommon, can result in serious complications and even death. Management of anal avulsion injuries remains controversial and challenging. This study aimed to investigate the clinical effects of treating large skin and subcutaneous tissue avulsion injuries in the perianal, sacral, and perineal regions with island flaps or skin graft combined with vacuum assisted closure. Methods Island flaps or skin graft combined with vacuum assisted closure, diverting ileostomy, the rectum packed with double-lumen tubes around Vaseline gauze, negative pressure drainage with continuous distal washing, wounds with skin grafting as well as specialized treatment were performed. Results The injuries healed in all patients. Six cases had incomplete perianal avulsion without wound infection. Wound infection was seen in four cases with annular perianal avulsion and was controlled, and the separated prowl lacuna was closed. The survival rate in 10 patients who underwent skin grafting was higher than 90%. No anal stenosis was observed after surgery, and ileostomy closure was performed at 3 months (six cases) and 6 months (four cases) after surgery, respectively. Conclusions Covering a wound with an island flap or skin graft combined with vacuum assisted closure is successful in solving technical problems, protects the function of the anus and rapidly seals the wound at the same time.

Here we report a graphene supported carbon-coated-LiNi1/3Co1/3Mn1/3O2 hybrid cathode material synthesized by combining polyvinyl pyrrolidone and graphene as double carbon sources. In this composite, the amorphous carbon pyrolyzed from polyvinyl pyrrolidone is tightly covered on the surface of LiNi1/3Co1/3Mn1/3O2 particles and graphene supports or links these LiNi1/3Co1/3Mn1/3O2 particles. Under the synergistic effect of amorphous carbon coating layer and graphene support, this hybrid cathode possesses superior rate capability and excellent cycle performance in both half and full cells. For example, as an electrode in half cell, it delivers the highest initial capacity of 201.1 mAh g-1 and the largest capacity retention ratio of 86.6% after 100 cycles at 0.5 C compared with other three LiNi1/3Co1/3Mn1/3O2 composites. Also, as a cathode electrode in full cell, the graphene supported carbon-coated-LiNi1/3Co1/3Mn1/3O2 hybrid material still shows better electrochemical performance than pristine LiNi1/3Co1/3Mn1/3O2. This co-modification method with pyrolytic carbon and graphene provides an economical and effective solution to develop high-voltage layered oxide cathode materials for high performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

CuS/graphene composite has been synthesized by the one-pot hydrothermal method using thiourea as the sulfur source and reducing agent. The formation of CuS nanoparticles and the reduction of graphene oxide occur simultaneously during the hydrothermal process, which enables a uniform dispersion of CuS nanoparticles on the graphene nanosheets. The electrochemical performance of CuS/graphene composite was studied as anode materials for lithium ion batteries. The obtained CuS/graphene composite exhibits a relative high reversible capacity and good cycling stability. The good electrochemical performance of CuS/graphene composite can be attributed to graphene, which improves the electronic conductivity of composite and enhances the interfacial stability of electrode and electrolyte. [ABSTRACT FROM AUTHOR]

Chemically activated graphene/porous Si@SiOx (CAG/Si@SiOx) composite has been synthesized via magnesiothemic reduction of mesoporous SiO2 (MCM-48) to porous Si@SiOx and dispersing in the suspension of chemically activated graphene oxide (CAGO) followed by thermal reduction. The porous Si@SiOx particles are well encapsulated in chemically activated graphene (CAG) matrix. The resulting CAG/Si@SiOx composite exhibits a high reversible capacity and excellent cycling stability up to 763 mAh g-1 at a current density of 100 mA g-1 after 50 cycles. The porous structure of CAG layer and Si@SiOx is beneficial to accommodate volume expansion of Si during discharge and charge process and the interconnected CAG improves the electronic conductivity of composite. [ABSTRACT FROM AUTHOR]

SnS/graphene nanocomposite has been prepared through a simple one-step and in situ method using thiourea as the sulfur source and reducing agent. The formation of SnS nanoparticles and the reduction of graphene oxide occur simultaneously during the hydrothermal process. The SnS nanoparticles are dispersed uniformly on graphene nanosheets and the SnS/graphene nanocomposite exhibits a relatively high reversible capacity and good cycling stability. The excellent electrochemical performance can be attributed to graphene, which prevents the agglomeration of SnS nanoparticles and improves the electronic conductivity of overall nanocomposite. The SnS/graphene nanocomposite combines the advantages of the good cycling stability of graphene and the high capacity of SnS nanoparticles. [ABSTRACT FROM AUTHOR]

Cadmium-incorporated Li2FeSiO4/C composites have been successfully synthesized by a solid-state reaction assisted with refluxing. The effect and mechanism of Cd-modification on the electrochemical performance of Li2FeSiO4/C were investigated in detail by X-ray powder diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Raman spectra, transmission electron microscopy, positron annihilation lifetime spectroscopy and Doppler broadening spectrum, and electrochemical measurements. The results show that Cd not only exists in an amorphous state of CdO on the surface of LFS particles, but also enters into the crystal lattice of LFS. Positron annihilation lifetime spectroscopy and Doppler broadening spectrum analyses verify that Cd-incorporation increases the defect concentration and the electronic conductivity of LFS, thus improve the Li1-ion diffusion process. Furthermore, our electrochemical measurements verify that an appropriate amount of Cd-incorporation can achieve a satisfied electrochemical performance for LFS/C cathode material. [ABSTRACT FROM AUTHOR]

A novel CdO and carbon co-coated LiFePO4 (LFP) cathode material has been synthesized, and the effect of CdO on the physicochemical properties and electrochemical performance has been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM) and electrochemical measurements. The results show that the LFP/(C+CdO) particles are coated with a mixed layer (about 2~3 nm) combined by amorphous carbon and CdO. Compared to the LFP/C electrode, the capacity retention ratio and high C-rate performance for LFP/(C+CdO) have been effectively improved, which is due to the enhanced structural stability, the reduced charge-transfer resistance, and the increased electronic conductivity. Therefore, the CdO and carbon co-coating is an effective surface modification technique. [ABSTRACT FROM AUTHOR]

GaMnN/GaN multilayers and conventional GaMnN single layers are grown by metal-organic chemical vapor deposition. Both kinds of samples show room-temperature ferromagnetism. After thermal annealing, the sample with GaMnN/GaN multilayer structure displays a larger coercivity and better thermal stability compared to the GaMnN single layer. The annealing effects on VGa related defects are observed from photoluminescence measurements. Moreover, a different magnetic behavior is also found in the annealed GaMnN films grown on different (n-type GaN and p-type GaN) templates. These kinds of structure-dependent magnetic behaviors indicate that defects or carriers transformation introduced during annealing may have important effects on the electronic structure of Mn ions and on the ferromagnetism. Our work may be helpful for further understanding the origin of ferromagnetism in GaN-based diluted magnetic semiconductors. [ABSTRACT FROM AUTHOR]