Layered Ag-graphene films synthesized by Gamma ray irradiation for stable lithium metal ano des in carb on ate-based electrolytes

Lithium metal batteries are considered as high energy density battery systems with very promising prospects and have bee n widely studied.However,The uncon trollable plating/strippi ng behavior,infinite volume change and den drites formation of lithium metal anode restrict the applicati on.The unc on trolled n ucleati on of lithium caused by the non uniform multi-physical field distributions,can lead to the undesirable lithium deposition.Herein,a graphene composite uniformly loaded with Ag nano-particles(Ag NPs)is prepared through a facile Gamma ray irradiation method and assembled into self-supported film with layered structure(Ag-rGO film).Whe n such film is used as a lithium metal an ode host,the uncontrolled deposition is converted into a highly nucleation-induced process.On one hand,the Ag NPs distributed between the in terlayers of graphe ne can preferentially induce lithium nu cleati on and en able uniform deposition morphology of lithium between interlayers.On the other hand,the stable layered graphene structure can accommodate volume change,stabilize the interface between anode and electrolyte and inhibit dendrites formation.Therefore,the layered Ag-rGO film as anode host can reach a high Coulombic efficiency over 93.3% for 200 cycle(786 h)at a current density of 1 mA cm^(-2) for 2 mAh cm^(-2) in carbonate-based electrolyte.This work proposes a facile Gamma ray irradiation method to prepare metal/3D-skeleton structure as lithium anode host and demonstrates the potential to regulate the lithium metal deposition behaviors via manipulating the distribution of lithiophilic metal(e.g.Ag)in 3D frameworks.This may offer a practicable thinking for the subsequent design of the lithium metal anode.

锂离子电池氧化亚硅负极结构优化和界面改性研究进展

氧化亚硅(SiO)作为锂离子电池负极材料,具有较高的理论比容量(~2043 mAh·g^(−1))以及合适的脱锂电位(<0.5 V),且原料储量丰富、制备成本较低、对环境友好,被认为是下一代高能量密度锂离子电池负极极具潜力的候选材料。然而,SiO在脱/嵌锂过程中存在着较严重的体积效应(~200%),易导致材料颗粒粉化、脱落,严重影响了SiO负极电极的界面稳定性和电化学性能。近年来,人们围绕SiO负极结构优化和界面改性开展了大量工作。本文先从SiO负极材料的结构特点出发,阐述了该材料面临的主要瓶颈问题;继而从SiO的结构优化、SiO/碳复合和SiO/金属复合等三方面,系统总结了迄今已有的SiO负极结构设计和界面调控策略,并分别对其方法特点、电化学性能以及二者间关联规律进行了比较和归纳,最后对SiO负极材料结构和界面改性的未来发展方向进行了展望。

ROS-responsive capsules engineered from EGCG-Zinc networks improve therapeutic angiogenesis in mouse limb ischemia

The successful treatment of limb ischemia requires that promote angiogenesis along with microenvironment improvement.Zinc ions have been reported to stimulate angiogenesis,but application was limited to the toxicity concerns.We hypothesized that zinc based metal-EGCG capsule(EGCG/Zn Ps)can achieve sustained release Zn2+resulting in reduced toxicity and improve angiogenesis as well as the improvement of microenvironment by ROS scavenging of EGCG.The surface morphology,zeta potential,infrared absorbance peaks and zinc ion release profile of the EGCG/Zn Ps were measured.In vitro,EGCG/Zn showed significantly antioxidant,antiinflammatory and induced cell migration effect.In addition,EGCG/Zn Ps enabled the sustained release of zinc ions,which reduced cytotoxicity and enhanced the secretion of vascular endothelial growth factor(VEGF)in vitro and in vivo.In mouse models of limb ischemia,EGCG/Zn Ps promoted angiogenesis and cell proliferation in ischemic tissues.Moreover,EGCG/Zn Ps group exhibited the most significant recovery of limb ischemic score,limb temperature and blood flow than other groups.In conclusion,EGCG/Zn Ps is a safe and promising approach to combine the merit of Zn2+and EGCG,thus enabling the direct application to limb ischemia.

Significant difference between sirolimus and paclitaxel nanoparticles in antiproliferation effect in normoxia and hypoxia: The basis of better selection of atherosclerosis treatment

Compared with paclitaxel,sirolimus has been more used in the treatment of vascular restenosis gradually as an anti-proliferative drug,but few basic studies have elucidated its mechanism.The anti-proliferative effects of sirolimus or paclitaxel have been demonstrated by numerous studies under normoxia,but few studies have been achieved focusing hypoxia.In this study,porcine carotid artery injury model and classical cobalt chloride hypoxia cell model were established.Sirolimus nanoparticles(SRM-NPs),paclitaxel nanoparticles(PTX-NPs)and blank nanoparticles(Blank-NPs)were prepared respectively.The effect of RPM-NPs on the degree of stenosis,proliferative index and the expression of PCNA after 28 days of porcine carotid artery injury model was evaluated.Compared with saline group and SRM groups,SRM-NPs group suppressed vascular stenosis,proliferative index and the expression of PCNA(P<0.01 and P<0.05).Endothelial cell(EC)and smooth muscle cell(SMC)were pre-treated with cobaltous chloride,followed by SRM-NPs,PTX-NPs,Blank-NPs or PBS control treating,the effects on cell proliferation,HIF-1 expression and glycolysis were detected.SRM-NPs could inhibit EC and SMC proliferation under hypoxia,while PTX-NPs couldn't(P<0.001).Significant differences between sirolimus and paclitaxel NPs in anti-proliferation effect under normoxia and hypoxia may due to the different inhibitory effects on HIF-1αexpression and glycolysis.In conclusion,these results suggest that sirolimus can inhibit the proliferation of hypoxic cells more effectively than paclitaxel.These observations may provide a basis for understanding clinical vascular stenosis therapeutic differences between rapamycin and paclitaxel.

Highly sensitive H_(2)O_(2)-scavenging nano-bionic system for precise treatment of atherosclerosis

In atherosclerosis,chronic inflammatory processes in local diseased areas may lead to the accumulation of reactive oxygen species(ROS).In this study,we devised a highly sensitive H_(2)O_(2)-scavenging nanobionic system loaded with probucol(RPP-PU),to treat atherosclerosis more effectively.The RPP material had high sensitivity to H_(2)O_(2),and the response sensitivity could be reduced from 40 to 10μmol/L which was close to the lowest concentration of H_(2)O_(2)levels of the pathological environment.RPP-PU delayed the release and prolonged the duration of PU in vivo.In Apolipoprotein E deficient(ApoE-/-)mice,RPP-PU effectively eliminated pathological ROS,reduced the level of lipids and related metabolic enzymes,and significantly decreased the area of vascular plaques and fibers.Our study demonstrated that the H_(2)O_(2)-scavenging nanobionic system could scavenge the abundant ROS in the atherosclerosis lesion,thereby reducing the oxidative stress for treating atherosclerosis and thus achieve the therapeutic goals with atherosclerosis more desirably.

Effect of electron-withdrawing groups in conjugated bridges： molecular engineering of organic sensitizers for dyesensitized solar cells

Four organic sensitizers containing quinoxaline or benzoxadiazole as an auxiliary electron acceptor in conjugated bridge were synthesized and utilized for dyesensitized solar cells （DSSCs）. It was found that the incorporation of different electron-withdrawing moieties can affect the absorption spectra, electronic properties, the interfacial interactions and then the overall conversion efficiencies significantly. Therefore, the appropriate selection of the auxiliary acceptor was important to optimize the photovoltaic performance of solar cells. Among these sensitizers, LI-44 based solar cell showed the best photovoltaic performance： a shortcircuit photocurrent density （Jsc） of 13.90 mA/cm2, an open-circuit photovoltage （Voc） of 0.66 V, and a fill factor （FF） of 0.66, corresponding to an overall conversion efficiency of 6.10% under standard global AM 1.5 solar light conditions.