Molybdenum disulfide(MoS2)was loaded on biocarbon using waste camellia dregs(CDs)as the carbon source,which was further coated with dopamine hydrochloride to construct biocarbon/MoS2 electrode composites.The electrochemical lithium storage performance of the composites with different MoS2 contents was investigated.SEM results demonstrated that the composite had a three-dimensional foam-like structure with MoS2 as the interlayer.XRD and HRTEM tests revealed that MoS2 interlayer spacing in the composite was expanded.XPS analysis showed that new Mo—N bonds were formed in the active material.The electrochemical tests showed that the composite with a MoS2 content of 63%had a high initial specific capacity of 1434 mA·h/g at a current density of 100 mA/g.After a long cycle at a high current,it also showed good cycling stability and the capacity retention was nearly 100%.In addition,it had good lithium ion deintercalation ability in the electrochemical kinetics test.
在磷酸钠碱性电解质中对单晶硅(100)进行阳极氧化处理,并将阳极氧化处理后的样品在模拟体液(simulated body fluid,SBF)中浸泡以考察其体外诱导骨状磷灰石沉积能力。用扫描电子显微镜观测体外浸泡前后样品的表面形貌,用电子能谱仪和X射线衍射仪研究阳极氧化后与体外浸泡不同时间后样品表面的成分。结果表明:单晶硅在10%的磷酸钠电解质中于5～20mA/cm2阳极氧化后,其表面原位形成火山口状结构,在SBF中浸泡1d后有磷灰石在单晶硅的阳极氧化层表面成核,浸泡6d后诱导形成了纳米骨状缺钙磷灰石层,体现出良好的体外诱导活性,表明阳极氧化处理是一种有希望应用于改善生物学与医学用单晶硅表面生物相容性的有效途径。
Perovskite ZnTiO3 was prepared through a new method which contained a hydrothermal process for the preparation of titanate nanotubes and an ion-exchange process.The titanate nanotubes were inferred to be H2Ti3O7·3H2O.X-ray diffraction（XRD）result revealed the presence of cubic perovskite phase of ZnTiO3.The unique chain-like morphology of ZnTiO3 was observed by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）.UV-Vis diffusive reflection spectra of ZnTiO3indicated that the absorbance obviously increased in the visible light region.The degradation rate of methyl orange solution（15 mg/L）reached 95.3%over ZnTiO3（0.3 g/L） after 20 min xenon light irradiation,which was higher than that using the commercial catalyst P25 under the same reaction condition.The degradation kinetic results follow the first-order equation and the rate constant is 0.1020.
Apatite coating with nanobelt structure was fabricated on single crystal silicon by a two-step method of electrodeposition at 1.0-2.0 mA/cm2 with DC power and vapor-thermal treatment(VTT) at 150-180℃ for 6 h over alkali medium.Scanning electron microscopy(SEM),X-ray diffractometry(XRD),and electron diffraction spectrometry(EDS) were employed to investigate the compositions and morphologies of specimens before or after vapor-thermal treatment.The results demonstrate that nanobelt crystals of coating,0.5-2 μm in width,100 nm in thickness,and 6-10 μm in length,are Ca-deficient apatite(CDA) with a mole ratio of Ca to P approximately of 1.60,which shows similarity of the nanobelt coating to inorganic phase in composition and to collagen in dimension appearing in human hard tissue.Induced nucleation and growth of bone-like apatite were observed on the nanobelt after soaking in a simulated body fluid(SBF) for 6 h and for 3 d,respectively,identifying that nanobelt has good ability for induction of bone-like apatite in SBF.
Shuttle effect is one of the most serious disadvantages in lithium-sulfur battery which results in poor cycle performance and hinders the commercialization of Li-S battery.To reduce the dissolution of polysulfides into the electrolyte and prolong the cycling stability,nanoparticle-stacked metal nitride derived from layered double hydroxides(LDHs)as an interlayer was inserted between sulfur cathode and separator to confine polysulfides by physical and chemical interactions.Meanwhile,the surface of metal nitride will form an oxide passivation layer.The passivation layer possesses hydrophilic metal-O group and provides a polar surface for strong binding with polysulfide.What’s more,the nanoparticlesstacked structure could immerge and retain electrolyte well,which could enhance the ability of promoting the electron exchange rate.The sulfur electrode with nanoparticle-stacked metal nitride interlayer has an excellent cycle performance owing to the interactions between metal nitride and polysulfides.The battery delivered an initial capacity of 764.6 m Ahg^(-1) and still possesses a capacity of 477.5 mAhg^(-1) with the retention of 62.4% after 800 cycles.
Zhen LiZhaoling MaYanyong WangRu ChenZhenjun WuShuangyin Wang
采用溶胶-凝胶法在单晶硅表面制备了磷灰石(apatite,AP)涂层。借助SEM、EDS、XRD研究了单晶硅表面AP涂层的形貌结构与成分特征,通过模拟体液(simulated body fluid,SBF)浸泡实验研究了硅基AP涂层的体外诱导性能。研究结果表明,在500℃保温2h即可使sol-gel层转变为较致密的AP涂层,700与800℃分别保温2h得到的硅基AP涂层晶体长大且出现间隙,涂层的结晶性随热处理温度升高而增加,在800℃处理未出现AP的分解;SBF中浸泡1周后,AP涂层未出现剥离单晶硅的现象,且能够诱导骨状磷灰石新沉积层的形成,体现出较好的体外诱导性能。
