Silicon Nanoparticles Embedded in Chemical-Expanded Graphite through Electrostatic Attraction for High-Performance Lithium-Ion Batteries.

Silicon (Si) is a promising next-generation anode for high-energy-density lithium-ion batteries. The application of silicon/carbon (Si/C) composites with high Si content is hindered by the huge volume change and insecure electrochemical interface of the Si anode. Herein, chemical-expanded graphite (CEG) is used as a carbon matrix to form Si@CEG/C composites with an embedded structure. CEG with an abundant pore structure and electropositivity can well disperse and accommodate a mass of Si nanoparticles (Si NPs). With the flexibility and porosity of CEG, the embedded structure of Si NPs fixed in an expanded graphite layer can adopt the volume change of Si NPs and offer the abundant path of diffusion of lithium-ion, which leads to a moderate cycle and rate performance. Si@CEG/C exhibits a high reversible capacity of 1232.4 mA h g-1 at a current density of 0.5 A g-1 and with a capacity retention rate of 87% after 200 cycles. This embedded structure of Si/C composites built by CEG is meaningful for the structure design of the Si-based anode with higher specific capacity, active material utilization, and satisfactory cycle stability.

Understanding and Controlling the Nucleation and Growth of Zn Electrodeposits for Aqueous Zinc-Ion Batteries.

Aqueous Zn-ion batteries (AZBs) have been proposed as one of the most promising electrical energy-storage systems due to their low cost, high safety, environmental friendliness, and high energy density. However, their application is impeded by the Zn dendrite growth, which may puncture the separator, causing an internal short circuit. Although numerous efforts have been devoted to alleviating dendrite issues by structural design, surface modification, or electrolyte optimization, there are few works focusing on the fundamental research to understand the formation of Zn dendrites, which is critical to address the dendrites issue. In this work, we have systematically investigated the nucleation and growth behaviors of Zn on a stainless steel substrate. We reveal the dependence of Zn growth morphology on cycling conditions (current density and areal capacity) and further elucidate the intricate correlation with cycle life. It is observed that higher current density corresponds to higher nuclei density with a smaller size of zinc deposits and lower areal capacity render smaller zinc flakes, which contributes to the long cycle life of Zn-ion batteries. Based on these findings, a seeding protocol is then proposed to improve the uniformity and compaction of the Zn electrode. The methodology and findings here can potentially be applied to study the nucleation and growth of other metals.

The tumor phototherapeutic application of nanoparticles constructed by the relationship between PTT/PDT efficiency and 2,6- and 3,5-substituted BODIPY derivatives.

BODIPY dyes have recently been used for photothermal and photodynamic therapy of tumors. However, complex multi-material systems, multiple excitation wavelengths and the unclear relationship between BODIPY structures and their PTT/PDT efficiency are still major issues. In our study, nine novel BODIPY near-infrared dyes were designed and successfully synthesized and then, the relationships between BODIPY structures and their PTT/PDT efficiency were investigated in detail. The results showed that modifications at position 3,5 of the BODIPY core with conjugated structures have better effects on photothermal and photodynamic efficiency than the modifications at position 2,6 with halogen atoms. Density functional theory (DFT) calculations showed that this is mainly due to the extension of the conjugated chain and the photoinduced electron transfer (PET) effect. By encapsulating BDPX-M with amphiphilic DSPE-PEG2000-RGD and lecithin, the obtained NPs not only show good water solubility and biological stability, but also could act as superior agents for photothermal and photodynamic synergistic therapy of tumors. Finally, we obtained BODIPY NPs that exhibited excellent photothermal and photodynamic effects at the same time under single irradiation with an 808 nm laser (photothermal conversion efficiency: 42.76%, A/A0: ∼0.05). In conclusion, this work provides a direction to design and construct phototherapeutic nanoparticles based on BODIPY dyes for tumor treatment.

Boosting the cycling stability of Ni-rich layered oxide cathode by dry coating of ultrastable Li3V2(PO4)3 nanoparticles.

Nickel (Ni)-rich layered oxides such as LiNi0.6Co0.2Mn0.2O2 (NCM622) represent one of the most promising candidates for next-generation high-energy lithium-ion batteries (LIBs). However, the pristine Ni-rich cathode materials usually suffer from poor structural stability during cycling. In this work, we demonstrate a simple but effective approach to improve the cycling stability of the NCM622 cathode by dry coating of ultrastable Li3V2(PO4)3-carbon (LVP-C) nanoparticles, which leads to a robust composite cathode (NCM622/LVP-C) without sacrificing the specific energy density compared with pristine NCM622. The optimal NCM622/LVP-C composite presents a high specific capacity of 162 mA h g-1 at 0.5 C and excellent cycling performance with 85.0% capacity retention after 200 cycles at 2 C, higher than that of the pristine NCM622 (67.6%). Systematic characterization confirms that the LVP-C protective layer can effectively reduce the side reactions, restrict the cation mixing of NCM622 and improve its structural stability. Moreover, the NCM622/LVP-C||graphite full cells also show a commercial-level capacity of 3.2 mA h cm-2 and much improved cycling stability compared with NCM622/LVP-C||graphite full cells, indicating the great promise for low-cost, high-capacity and long-life LIBs.

A multifunctional anode with P-doped Si nanoparticles in a stress-buffering network of poly-γ-glutamate and graphene.

Here, a new strategy is reported for the preparation of a new class of nanocomposite anode materials consisting of ppm-level phosphorus-doped Si nanoparticles (P-Si) wrapped in a network of poly-γ-glutamate and graphene. The network produces not only a conductivity-enhanced conduit but also a mechanical stress buffer. The incorporation of poly-γ-glutamate in the nanocomposite enables self-healing capability and maintains the electrode structural integrity. This multifunctionality has significant implications for advancing the design of stable Si-based nanomaterials as high-performance anodes in Li-ion batteries.

Understanding the formation of ultrathin mesoporous Li4Ti5O12 nanosheets and their application in high-rate, long-life lithium-ion anodes.

Two-dimensional nanosheet-like materials with ultra-small thickness and uniform porous structures hold great promise for high-rate and long-life lithium-ion batteries. In this work, pure ultrathin mesoporous Li4Ti5O12 nanosheets are fabricated by combining a facile solvothermal synthesis with a calcination process. The detailed formation mechanism of ultrathin mesoporous Li4Ti5O12 nanosheets is systematically investigated, which identified the key factors that control the structure development. The unique structural features including ultra-small thickness, large specific surface area and uniform mesoporous structures endow such materials with effective charge transport channels, abundant reaction active sites and inner-plain void space for improved structural stability. As a result, the ultrathin mesoporous Li4Ti5O12 nanosheets offer nearly theoretical capacity (174 mA h g-1 at 1 C), very high rate capability (e.g., 145 mA h g-1 at 50 C), and excellent cycling stability (95% capacity retention after 2500 cycles at 20 C), suggesting their great promise as anode materials for ultrahigh-power and long-life lithium-ion batteries.

[High-performance liquid chromatography-mass spectrometry-based serum metabolic profiling in patients with HBV-related hepatocellular carcinoma].

OBJECTIVE: To explore the diagnostic value of the serum metabolites identified by high-performance liquid chromatography-mass spectrometry (HPLC/MS) for hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). METHODS: A total of 126 patients admitted to Tianjin Third Central Hospital were enrolled, including 27 patients with HBV-related hepatitis with negative viral DNA (DNA-N), 24 with HBV-related hepatitis with positive viral DNA, 24 with HBV-related liver cirrhosis, 27 with HBV-related HCC undergoing surgeries or radiofrequency ablation, and 24 with HBV-related HCC receiving interventional therapy, with 25 healthy volunteers as the normal control group. Serum samples were collected from all the subjects for HPLC/MS analysis, and the data were pretreated to establish an orthogonal partial least- squares discriminant analysis (OPLS-DA) model. The differential serum metabolites were preliminarily screened by comparisons between the HBV groups and the control group, and the characteristic metabolites were identified according to the results of non-parametric test. The potential clinical values of these characteristic metabolites were evaluated using receiver operator characteristic curve (ROC) analysis. RESULTS: A total of 25 characteristic metabolites were identified in the HBV- infected patients, including 9 lysophosphatidylcholines, 2 fatty acids, 17α-estradiol, sphinganine, 5-methylcytidine, vitamin K2, lysophosphatidic acid, glycocholic acid and 8 metabolites with few reports. The patients with HBV- related HCC showed 22 differential serum metabolites compared with the control group, 4 differential metabolites compared with patients with HBV-related liver cirrhosis; 10 differential metabolites were identified in patients with HBV-related HCC receiving interventional therapy compared with those receiving surgical resection or radiofrequency ablation. From the normal control group to HBV-related HCC treated by interventional therapy, many metabolites underwent variations following a similar pattern. CONCLUSIONS: We identified 25 characteristic metabolites in patients with HBV-related HCC, and these metabolites may have potential clinical values in the diagnosis of HBV-related HCC. The continuous change of some of these metabolites may indicate the possibility of tumorigenesis, and some may also have indications for the choice of surgical approach.

An integrated targeting drug delivery system based on the hybridization of graphdiyne and MOFs for visualized cancer therapy.

Multimodal therapies have been regarded as promising strategies for cancer treatment as compared to conventional drug delivery systems that have various drawbacks in either low loading content, uncontrolled release, non-targeting or biotoxicity. We have developed a multifunctional three-dimensional tumor-targeting drug delivery system, Fe3O4@UIO-66-NH2/graphdiyne (FUGY), based on the hybridization of a novel two-dimensional material, graphdiyne (GDY), with a metal organic framework (MOFs) structure, Fe3O4@UIO-66-NH2 (FU). The FU MOF structure has superior ability for magnetic targeting, and was constructed by an in situ growth method in which it was surface-installed with GDY via amide bonds, as a carrier of anticancer drugs. The anticancer drug doxorubicin (DOX) was loaded onto FUGY and served as both an anticancer drug to treat the tumor and a fluorescence probe to ascertain the location of FUGY. The results show that FUGY exhibits a high drug loading content of 43.8% and an effective drug release around the tumor cells at pH 5.0. In particular, fluorescence imaging demonstrates that FUGY can deliver more anticancer drugs to tumor tissue than conventional drug delivery systems. Furthermore, FUGY exhibits superior therapeutic efficiencies with negligible side effects as compared to the direct administration of free DOX, both in vitro and in vivo. The obtained FUGY drug delivery system possesses ideal biocompatibility, sustained drug release, effective chemotherapeutic efficacy, and specific targeting abilities. Such a multimodal therapeutic system can facilitate new possibilities for multifunctional drug delivery systems.

Chitosan-Induced Synthesis of Hierarchical Flower Ridge-like MoS2/N-Doped Carbon Composites with Enhanced Lithium Storage.

Continuous hierarchical MoS2/C micro/nanostructured composite with strong structural stability and efficient lithium ion and electron transport channels is an urgent need for its successful application in lithium ion battery anode materials. In this study, continuous hierarchical flower ridge-like MoS2/N-doped carbon micro/nanocomposite (MoS2/NC) was first synthesized through a simple chitosan-induced one-pot hydrothermal and postsintering method. The amino-containing chitosan is demonstrated to be important not only in nitrogen-doped carbon source, soft template, and surfactant but also in controlling the interlayer distance between adjacent MoS2 layers. The detailed hierarchical structure, phase characteristics, the number of MoS2 stacked layers, and interlayer distance were characterized using a scanning electron microscope, transmission electron microscope, X-ray diffraction, and so forth. It reveals that the interconnected nanoflowers composed of few-layer MoS2 (≤3 layers) nanoflakes with an expanded interlayer distance vertically grow on two-dimensional N-doped carbon nanosheets in the MoS2/NC composite. When examined as anode of lithium ion batteries, this unique hierarchical MoS2/NC micro/nanostructure shows better electrochemical performance. The electrode delivers a reversible capacity of 904.7 mA h g-1 at 200 mA g-1 after 100 cycles, outstanding cycle stability at high rates (742, 686, 534 mA h g-1 at 500, 1000, 2000 mA g-1 after 400 cycles, respectively) and superior rate performance. The above synthesis strategy is a good choice for constructing other hierarchical transition-metal disulfides or oxides and carbon micro/nanostructures to improve their electrochemical performance.

Self-Assembly of Silicon@Oxidized Mesocarbon Microbeads Encapsulated in Carbon as Anode Material for Lithium-Ion Batteries.

The utilization of silicon/carbon composites as anode materials to replace the commercial graphite is hampered by their tendency to huge volumetric expansion, costly raw materials, and complex synthesis processes in lithium-ion batteries. Herein, self-assembly method is successfully applied to prepare hierarchical silicon nanoparticles@oxidized mesocarbon microbeads/carbon (Si@O-MCMB/C) composites for the first time, in which O-MCMB core and low-cost sucrose-derived carbon shell not only effectively enhance the electrical conductivity of the anode, but also mediate the dramatic volume change of silicon during cycles. At the same time, the carbon can act as "adhesive", which is crucial in enhancing the adhesive force between Si and O-MCMB in the composites. The as-obtained Si@O-MCMB/C delivers an initial reversible capacity of 560 mAh g-1 at 0.1 A g-1, an outstanding cyclic retention of 92.8% after 200 cycles, and respectable rate capability. Furthermore, the synthetic route presented here is efficient, less expensive, simple, and easy to scale up for high-performance composites.

Metabolic profiling of hepatitis B virus-related hepatocellular carcinoma with diverse differentiation grades.

The most effective diagnostic tool for the majority of hepatocellular carcinoma (HCC) patients is determining the differentiation grade of their tumors. However liver biopsies, which are currently the most effective way of determining tumor differentiation grade, have several limitations. The present study was designed to select serum characteristic metabolites that correlate with the differentiation grades of hepatitis B virus (HBV)-related HCC, and so could be used in the clinic as a non-invasive method of differentiating patients with different grades of HCC. A total of 58 patients with HBV-related HCC were included in the present study, and divided into three groups according to their tumor differentiation grade. A further 20 patients with HBV-related liver cirrhosis and 19 healthy volunteers were enrolled. Ultra-performance liquid chromatography-mass spectrometry was used to analyze endogenous metabolites. Multivariate statistical analysis was used to examine the data using MZmine 2.0 software. The 14 metabolites that were highly correlated with specific differentiation grades of HCC were then selected for additional study. Receiver operator characteristic curve analysis was used to evaluate their clinical value. In total, 5 metabolites were finally identified, including lysophosphatidylcholine (16:0), oleamide, monoglyceride (0:0/15:0/0:0), lysophosphatidylcholine (18:0) and lysophosphatidylcholine [22:5(7Z,10Z,13Z,16Z,19Z)]. All these metabolites exhibited an excellent ability to distinguish different types of HCC with various differentiation grades and the area under the curve of these metabolites was up to 0.942, showing promising clinical value.