Lithium (Li) metal anodes have the highest theoretical capacity and lowest electrochemical potential making them ideal for Li metal batteries (LMBs). However, Li dendrite formation on the anode impedes the proper discharge capacity and practical cycle life of LMBs, particularly in carbonate electrolytes. Herein, we developed a reactive alternative polymer named P(St-MaI) containing carboxylic acid and cyclic ether moieties which would in situ form artificial polymeric solid electrolyte interface (SEI) with Li. This SEI can accommodate volume changes and maintain good interfacial contact. The presence of carboxylic acid and cyclic ether pendant groups greatly contribute to the induction of uniform Li ion deposition. In addition, the presence of benzyl rings makes the polymer have a certain mechanical strength and plays a key role in inhibiting the growth of Li dendrites. As a result, the symmetric Li||Li cell with P(St-MaI)@Li layer can stably cycle for over 900 h under 1 mA cm−2 without polarization voltage increasing, while their Li||LiFePO4 full batteries maintain high capacity retention of 96 % after 930 cycles at 1C in carbonate electrolytes. The innovative strategy of artificial SEI is broadly applicable in designing new materials to inhibit Li dendrite growth on Li metal anodes. 相似文献
Initial cell evaluation on alginate/hydroxyapatite block was investigated. Sodium alginate with 1, 3 and 5% concentration was obtained via neutral extraction of locally obtained brown seaweed, Sargassumpolycystum. Commercially available hydroxyapatite (HAp) powder was pressed uniaxially at 3 MPa to obtain the HAp block. The HAp block was then sintered at 900̊C. The sintered HAp block was then immersed in the sodium alginate solution at different concentration for 24 hours under vacuum condition. Morphological observations show that normal cell growth was observed on alginate/HAp blockafter post treatment for day 1 and 2. However, the cell starts to show some distinct morphological changes when compared to the control cells for day 5 and 7. Cell viability assay results shows that a consistent cell growth was obtained with HAp block incorporated with 3 and 5% sodium alginate. While HAp block without the incorporation of sodium alginate and HAp block incorporated with 1% sodium alginate concentration shows inconsistent cell growth. Initial cell evaluation results suggest that alginate/HAp block shows no toxicity on cell attachment and proliferation. 相似文献
Protein adsorption characteristics of calcium hydroxyapatite (Hap) modified with pyrophosphoric acids (PP(a)) were examined. The PP(a) modified Hap particles (abbreviated as PP-Hap) possessed anchored polyphosphate (PP: P-{O-PO(OH)}(n)-OH) branches on their surfaces. The proteins of bovine serum albumin (BSA: isoelectric point (iep)=4.7, molecular mass (M(s))=67,200 Da, acidic protein), myoglobin (MGB: iep=7.0, M(s)=17,800 Da, neutral protein), and lysozyme (LSZ: iep=11.1, M(s)=14,600 Da, basic protein) were examined. The zeta potential (zp) of PP-Hap particles as a function of pH overlapped; zp-pH curves were independent of the concentration of pyrophosphoric acids (abbreviated as [PP(a)]) used for modifying Hap surface. The saturated amounts of adsorbed BSA (Delta n(ads)(BSA)) were increased three-fold by the surface modification with PP(a) though they were independent of the [PP(a)]. Furthermore, the fraction of BSA desorption was independent of the [PP(a)]. This enhancement of BSA adsorption onto the PP-Hap is due to the hydrogen bonding between oxygen and OH groups of the PP-branches and functional groups of BSA molecules. In the case of LSZ, a more higher adsorption enhancement was observed; the saturated amount of adsorbed LSZ (Delta n(ads)(LSZ)) for Hap modified at [PP(a)]=6 mmol/dm(3) was nine-fold than that for Hap unmodified. This remarkable adsorption enhancement was explained by a three-dimensional binding mechanism; LSZ molecules were trapped inside of the PP-branches. Hence, a fraction of LSZ desorption was decreased with an increase in the [PP(a)]; as more PP-branches are presented on the surface the higher retardation of LSZ desorption was induced. It was expected from their small size that MGB adsorb between the PP-branches as well as LSZ. However, the amounts of adsorbed MGB (Delta n(ads)(MGB)) did not vary and were independent of the [PP(a)] due to the small numbers of functional groups of MGB. In addition, no dependence of the fraction of MGB desorption on the [PP(a)] was observed. The results of zp for all the protein systems supported the mode of protein adsorption discussed. The anchored structure of the PP-branches developed on the Hap surface to provide three-dimensional protein adsorption spaces was proved by a comparative experiment that was elucidating the effect of pyrophosphate ions for BSA adsorption onto Hap. 相似文献
Visible light emission of dental hard substances excited by high-power infrared pulses of a tunable TEA CO2 laser has been investigated. A clear correlation between observed visible light emission, plasma formation as well as ablation of dental hard tissue has been demonstrated. Both, the highly nonlinear infrared to visible upconversion process and the ablation efficiency show a sharp spectral resonance close to a vibrational mode of PO4 at 1090 cm-1 in dental enamel and dentin. The influence of strong infrared light impulses on dental hard tissue is examined by performing upconversion studies of visible light emission of human dental enamel and dentin. Our experimental setup allows one to determine the plasma formation threshold being important in dental surgery. 相似文献
Stainless steel 306 is implanted with various doses of nitrogen ions using a 2?MV pelletron accelerator for the improvement of its surface biomedical properties. Raman spectroscopy reveals incubation of hydroxyapatite (HA) on all the samples and it is found that the growth of incubated HA is greater in higher ion dose samples. SEM profiles depict uniform growth and greater spread of HA with higher ion implantation. Human oral fibroblast response is also found consistent with Raman spectroscopy and SEM results; the cell viability is found maximum in samples treated with the highest (more than 300%) dose. XRD profiles signified greater peak intensity of HA with ion implantation; a contact angle study revealed hydrophilic behavior of all the samples but the treated samples were found to be lesser hydrophilic compared to the control samples. Nitrogen implantation yields greater bioactivity, improved surface affinity for HA incubation and improved hardness of the surface. 相似文献
Molecular self‐assembly is emerging as a viable ‘bottom‐up’ approach to build stable organic/inorganic nanometer‐scale blocks. Herein, under the conditions of appropriate pH and ionic strength, soy globulin 7S or 11S were coprecipitated with hydroxyapatite (HAp) or aragonite (Arag), respectively, to fabricate two organic/inorganic hybrids: 7S/HAp and 11S/Arag. Results from high‐resolution transmission electron microscopy show that the hybrids exhibit a nanosized core–shell structure with globulin monomer 7S or 11S as core and HAp or Arag as shells. 7S/HAp and 11S/Arag present a disk and hexagon shape, respectively. After calcinations, monodispersed HAp without support from globulins existed as nanospheres. It was revealed that the globulin as host induces the self‐assembly and growth layer by layer of HAp or Arag nanocrystals. The factors of molecular recognition and surface potential definitely affected the size and shape of the hierarchical blocks. This work provided a novel pathway to controllably synthesize a wide variety of precise plant protein/biomineral hybrid biomaterials.