Nanoscale Visualization of Lithium Plating/Stripping Tuned by On-site Formed Solid Electrolyte Interphase in All-Solid-State Lithium-Metal Batteries.

The interfacial processes, mainly the lithium (Li) plating/stripping and the evolution of the solid electrolyte interphase (SEI), are directly related to the performance of all-solid-state Li-metal batteries (ASSLBs). However, the complex processes at solid-solid interfaces are embedded under the solid-state electrolyte, making it challenging to analyze the dynamic processes in real time. Here, using in situ electrochemical atomic force microscopy and optical microscopy, we directly visualized the Li plating/stripping/replating behavior, and measured the morphological and mechanical properties of the on-site formed SEI at nanoscale. Li spheres plating/stripping/replating at the argyrodite solid electrolyte (Li6 PS5 Cl)/Li electrode interface is coupled with the formation/wrinkling/inflating of the SEI on its surface. Combined with in situ X-ray photoelectron spectroscopy, details of the stepwise formation and physicochemical properties of SEI on the Li spheres are obtained. It is shown that higher operation rates can decrease the uniformity of the Li+ -conducting networks in the SEI and worsen Li plating/stripping reversibility. By regulating the applied current rates, uniform nucleation and reversible plating/stripping processes can be achieved, leading to the extension of the cycling life. The in situ analysis of the on-site formed SEI at solid-solid interfaces provides the correlation between the interfacial evolution and the electrochemical performance in ASSLBs.

Interfacial Evolution of the Solid Electrolyte Interphase and Lithium Deposition in Graphdiyne-Based Lithium-Ion Batteries.

All-carbon graphdiyne (GDY)-based materials have attracted extensive attention owing to their extraordinary structures and outstanding performance in electrochemical energy storage. Straightforward insights into the interfacial evolution at GDY electrode/electrolyte interface could crucially enrich the fundamental comprehensions and inspire targeted regulations. Herein, in situ optical microscopy and atomic force microscopy monitoring of the GDY and N-doped GDY electrodes reveal the interplay between the solid electrolyte interphase (SEI) and Li deposition. The growth and continuous accumulation of the flocculent-like SEI is directly tracked at the surface of GDY electrode. Moreover, the nanoparticle-shaped SEI homogeneously propagates at the interface when N configurations are involved, providing a critical clue for the N-doping effects of stabilizing interfaces and homogenizing Li deposition. This work probes into the dynamic evolution and structure-reactivity correlation in detail, creating effective strategies for GDY-based materials optimization in lithium-ion batteries.

State-of-the-Art Review of Ground Penetrating Radar (GPR) Applications for Railway Ballast Inspection.

In the past 20 years, many studies have been performed on ballast layer inspection and condition evaluation with ground penetrating radar (GPR). GPR is a non-destructive means that can reflect the ballast layer condition (fouling, moisture) by analysing the received signal variation. Even though GPR detection/inspection for ballast layers has become mature, some challenges still need to be stressed and solved, e.g., GPR indicator (for reflecting fouling level) development, quantitative evaluation for ballast fouling levels under diverse field conditions, rapid GPR inspection, and combining analysis of GPR results with other data (e.g., track stiffness, rail acceleration, etc.). Therefore, this paper summarised earlier studies on GPR application for ballast layer condition evaluation. How the GPR was used in the earlier studies was classified and discussed. In addition, how to correlate GPR results with ballast fouling level was also examined. Based on the summary, future developments can be seen, which is helpful for supplementing standards of ballast layer evaluation and maintenance.

Surface Degradation of Single-crystalline Ni-rich Cathode and Regulation Mechanism by Atomic Layer Deposition in Solid-State Lithium Batteries.

Single-crystalline Ni-rich cathode (SC-NCM) has attracted increasing interest owing to its greater capacity retention in advanced solid-state lithium batteries (SSLBs), while suffers from severe interfacial instability during cycling. Here, via atomic layer deposition, Li3 PO4 is introduced to coat SC-NCM (L-NCM), to suppress undesired side reaction and enhance interfacial stability. The dynamic degradation and surface regulation of SC-NCM are investigated inside a working SSLB by in situ atomic force microscopy (AFM). We directly observe the uneven cathode electrolyte interphase (CEI) and surface defects on pristine SC-NCM particle. Remarkably, the formed amorphous LiF-rich CEI on L-NCM maintains its initial structure upon cycling, and thus endows the battery with improved cycling stability and excellent rate capability. Such on-site tracking provides deep insights into surface mechanism and structure-reactivity correlation of SC-NCM, and thus benefits the optimizations of SSLBs.

Revealing the High Salt Concentration Manipulated Evolution Mechanism on the Lithium Anode in Quasi-Solid-State Lithium-Sulfur Batteries.

Lithium-sulfur batteries are promising candidates of energy storage devices. Both adjusting salt/solvent ratio and applying quasi-solid-state electrolytes are regarded as effective strategies to improve the lithium (Li) anode performance. However, reaction mechanisms and interfacial properties in quasi-solid-state lithium-sulfur (QSSLS) batteries with high salt concentration are not clear. Here we utilize in-situ characterizations and molecular dynamics simulations to unravel aforesaid mysteries, and construct relationships of electrolyte structure, interfacial behaviour and performance. The generation mechanism, formation process, and mechanical/chemical/electrochemical properties of the anion-derived solid electrolyte interphase (SEI) are deeply explored. Li deposition uniformity and dissolution reversibility are further tuned by the sustainable SEI. These straightforward evidences and deepgoing studies would guide the electrolyte design and interfacial engineering of QSSLS batteries.

Does national air quality monitoring reduce local air pollution? The case of PM2.5 for China.

Fine particulate matter (PM2.5) has become a major pressing challenge for China and remains a concern of its central government. This paper draws on a natural experiment generated by the National Ambient Air Quality Monitoring Network (NAAQMN) program in China to explore whether national air quality monitoring reduces local air pollution. In this study, we use a city-level dataset for 4200 Chinese cities covering 2001-2015 and a difference-in-differences (DID) assessment design to assess the impact of the NAAQMN program on local PM2.5 emissions in China. The results suggest that the NAAQMN program significantly reduces the local PM2.5 concentrations by 1.325 mg/m3, and each additional NAAQMN program will cause a decrease of 0.154 mg/m3 in the local PM2.5 concentrations. Furthermore, we determine the heterogeneous impacts of the NAAQMN program on local PM2.5 emission levels through the local government leaders' characteristics, PM2.5 emission levels, and economic development levels. In addition, a mediation effect is found between the NAAQMN program and local PM2.5 emissions through the efficiency of environmental governance. The Chinese government should continue to promote the implementation of the NAAQMN program by promoting the NAAQMN program to the county and rural areas as well as adding the sites of the NAAQMN program in the existing cities. Also, during the process of promoting the NAAQMN program, sufficient differentiation in policies should be developed for different cities.

Current-Density Regulating Lithium Metal Directional Deposition for Long Cycle-Life Li Metal Batteries.

Uncontrolled dendrite formation in the high energy density of lithium (Li) metal batteries (LMBs) may pose serious safety risks. While numerous studies have attempted to protect separators, these proposed methods fail to effectively inhibit upward dendrite growth that punctures through the separator. Here, we introduce a novel "orientated-growth" strategy that transfers the main depositional interface to the anode/current collector interface from the anode/separator interface. We placed a layer of cellulose/graphene carbon composite aerogel (CCA) between the current collector and the anode (LCL-bottom). This layer works as a charge organizer that induces a high current density and encourages Li to deposit at the anode/current collector interface. Both in situ and ex situ images of the electrode demonstrate that the anode part of the cell has been flipped; with the newly deposited particles facing the current collector and the smooth surface facing the separator. The electrode in half and full cells showed outstanding cyclic stability and rate capability, with the LCL-bottom/LFP full cell capable of maintaining 94 % of its initial capacity after 1000 cycles.

Dynamic Evolution of a Cathode Interphase Layer at the Surface of LiNi0.5Co0.2Mn0.3O2 in Quasi-Solid-State Lithium Batteries.

Intensive understanding of the surface mechanism of cathode materials, such as structural evolution and chemical and mechanical stability upon charging/discharging, is crucial to design advanced solid-state lithium batteries (SSLBs) of tomorrow. Here, via in situ atomic force microscopy monitoring, we explore the dynamic evolution process at the surface of LiNi0.5Co0.2Mn0.3O2 cathode particles inside a working SSLB. The dynamic formation process of the cathode interphase layer, with an inorganic-organic hybrid structure, was real-time imaged, as well as the evolution of its mechanical property by in situ scanning of the Derjaguin-Muller-Toporov modulus. Moreover, different components of the cathode interphase layer, such as LiF, Li2CO3, and specific organic species, were identified in detailat different stages of cycling, which can be directly correlated with the impedance buildup of the battery. In addition, the transition metal migration and the formation of new phases can further exacerbate the degradation of the SSLB. A relatively stable cathode interphase is key to improving the performance of SSLBs. Our findings provide deep insights into the dynamic evolution of surface morphology, chemical components and mechanical properties of the cathode interphase layer, which are pivotal for the performance optimization of SSLBs.

Interfacial Evolution of Lithium Dendrites and Their Solid Electrolyte Interphase Shells of Quasi-Solid-State Lithium-Metal Batteries.

Unstable electrode/solid-state electrolyte interfaces and internal lithium dendrite penetration hamper the applications of solid-state lithium-metal batteries (SSLMBs), and the underlying mechanisms are not well understood. Herein, in situ optical microscopy provides insights into the lithium plating/stripping processes in a gel polymer electrolyte and reveals its dynamic evolution. Spherical lithium deposits evolve into moss-like and branch-shaped lithium dendrites with increasing current densities. Remarkably, the on-site-formed solid electrolyte interphase (SEI) shell on the lithium dendrite is distinctly captured after lithium stripping. Inducing an on-site-formed SEI shell with an enhanced modulus to wrap the lithium precipitation densely and uniformly can regulate dendrite-free behaviors. An in-depth understanding of lithium dendrite evolution and its functional SEI shell will aid in the optimization of SSLMBs.

One-pot synthesis of 3D Au nanoparticle clusters with tunable size and their application.

In general, the preparation of Au nanoparticle clusters (NPCs) is more challenging than that of nanoparticles. The traditional multi-step method for preparing Au NPCs is time consuming and highly sensitive to the reaction conditions. Here, we report a simple and feasible method for the rapid preparation of Au NPCs (∼30 min), in which Au (III) is reduced to Au (0) by trisodium citrate, and assembled into NPCs in the presence of a trace amount of cysteine. The surface plasmon resonance peak of the Au NPCs is tunable and ranged from visible to near-IR regions by varying the content of cysteine added. The growth process of Au NPCs was monitored by dynamic light scattering, UV-vis absorption spectroscopy and transmission electron microscopy. Their elemental composition, chemical state and molecular structure of the sample surface were measured by x-ray photoelectron spectroscopy. The proposed synthesis mechanism has guiding significance for the preparation of other NPCs. Au NPCs used as surface-enhanced Raman spectroscopy substrate has a good enhancement effect because of its unique morphology.

Enhanced Visible Light Photocatalytic Performance of G-C3N4 Photocatalysts Co-Doped with Gold and Sulfur for Degradation of Persistent Pollutant (Rhodamine B).

In order to overcome the intrinsic drawback of pristine g-C3N4, a nano-composite photo-catalyst Au/S-C3N4 with controllable nanoscale gold (Au) particles was successfully synthesized by a facile liquid chemical preparation process. It was found that the content of chloroauric acid (AuCl3 · HCl · 4H2O) play crucial role in both the diameter and the density of the Au nanoparticles. The results showed that as-prepared Au/S-C3N4 nanosheets with 2 wt% Au loaded content exhibited excellent photocatalytic decomposition of RhB under visible light irradiation as compared with other Au loadings (i.e., 1 wt%, 2 wt%, 3 wt%, 4 wt% and 6 wt%). The photocatalytic activity of Au/S-C3N4 with 2 wt% Au loading was twice higher than that of bare S-C3N4 (0.00955 min-1). The enhanced performance could be attributed to the synergic effect of gold and sulfur on g-C3N4. A possible mechanism for elucidating the better performance of Au/S-C3N4 is also proposed and discussed in detail in this work.

Comparative Study of Pure g-C3N4 and Sulfur-Doped g-C3N4 Catalyst Performance in Photo-Degradation of Persistent Pollutant Under Visible Light.

Graphitic carbon nitride (g-C3N4) and sulfur-doped g-C3N4 were prepared by pyrolysis of melamine and thiourea respectively. Their comparative performance was investigated for photo-degradation of a Rhodamine B (RhB) an organic toxic pollutant. The crystal structure, morphology, microscopic components and properties of the synthesized samples were characterized by XRD, TEM, FT-IR, photoluminescence (PL) emission spectroscopy and zeta potential. TG-DTA is a record of the process for pyrolysis of thiourea. Two simplified kinetic models, pseudo-first-order and pseudo-second-order were applied to predict the adsorption rate constants. Thermodynamic parameters, such as the change in free energy, enthalpy and entropy were also calculated to analyze the process of adsorption. Adsorption isotherms and equilibrium adsorption capacities were established by three well-known isotherm models including Langmuir, Freundlich and Dubinin-Radushkevich (D-R). Both samples were investigated for underlining the reaction mechanism during the photodegradation RhB process and then can be assigned to the overall reaction. The photosensitive hole is regarded as main oxidation species for the degradation by sulfur-doped g-C3N4, but not the exclusive way for g-C3N4. It is worth mentioning that the optimum operating condition can be obtained by orthogonal experiments.

The magnetic and adsorption properties of ZnO1-xSx nanoparticles.

Sulfur is easy to be incorporated into ZnO nanoparticles by the solution-combustion method. Herein, the magnetic and adsorption properties of a series of ZnO1-xSx (x = 0, 0.05, 0.1, 0.15, and 0.2) nanoparticles were systematically investigated. The X-ray diffraction patterns show that the as-prepared ZnO1-xSx nanoparticles have the hexagonal wurtzite structure of ZnO with a low sulfur content that gradually transforms into the zinc blende structure of ZnS when the x value is greater than 0.1. PL spectra show several bands due to different transitions, which have been explained by the recombination of free excitons or defect-induced transitions. The introduction of sulfur not only modifies the bandgap of ZnO, but also impacts the concentration of Zn vacancies. The as-prepared ZnO shows weak room-temperature ferromagnetism, and the incorporation of sulfur improves the ferromagnetism owing to the increased concentration of Zn vacancies, which may be stabilized by the doped sulfur ions. The adsorption capability of ZnO1-xSx nanoparticles has been significantly improved, and the process can be well described by the pseudo-first-order kinetic model and the Freundlich isotherm model. The mechanism has been confirmed to be due to the active sulfate groups existing in zinc oxysulfide nanoparticles.

Stability of Li1.3Al0.3Ti1.7(PO4)3-Based Composite Electrolytes against Lithium Anodes Enhanced by Uniform Surface Coating of Two-Dimensional Graphene-like C3N4 on Particle Surfaces.

All-solid-state lithium (Li) batteries have attracted considerable interest due to their potential in high energy density as well as safety. However, the realization of a stable Li/solid-state electrolyte (SSE) interface remains challenging. Herein, two-dimensional graphene-like C3N4 (g-C3N4) as a coating layer on Li1.3Al0.3Ti1.7(PO4)3 (LATP) electrolyte (LATP@CN) has been applied to construct the stable Li/SSE interface. The g-C3N4 layer is uniformly coated on the LATP surface using the in situ calcination method, which not only enhances the dispersibility of LATP particles in poly(ethylene oxide) (PEO) through the interaction between surface functional groups but also suppresses the side reactions between Li and LATP. The coating layer can effectively improve the interfacial stability. As a result, the conductivity and stability of the obtained composite solid-state electrolytes (CSEs) against Li are enhanced. The Li∥CSEs∥Li symmetric cells stably cycle for 670 and 600 h at 0.1 and 0.2 mA cm-2, respectively. The Li∥CSEs∥LiFePO4 cells stably cycle more than 100 times at 0.1 and 0.2 C with a capacity retention rate of about 86% and 88%, respectively. This work inspires a new strategy to avoid the reactions between LATP and Li.

CXCL1-CXCR2 axis mediates inflammatory response after sciatic nerve injury by regulating macrophage infiltration.

Macrophages play a crucial role in the inflammatory response following sciatic nerve injury. Studies have demonstrated that C-X-C motif chemokine (CXCL) 1 recruit macrophages by binding to C-X-C chemokine receptor (CXCR) 2 and participates in the inflammatory response of various diseases. Based on these findings, we aimed to explore the role of the CXCL1-CXCR2 axis in the repair process after peripheral nerve injury. Initially, we simulated sciatic nerve injury and observed an increased expression of CXCL1 and CXCR2 in the nerves of the injury group. Both in vivo and in vitro experiments confirmed that the heightened CXCL1 expression occurs in Schwann cells and is secreted, while the elevated CXCR2 is expressed by recruited macrophages. In addition, in vitro experiments demonstrated that the binding of CXCL1 to CXCR2 can activate the NLRP3 inflammasome and promote the production of interleukin-1 beta (IL-1ß) in macrophages. However, after mice were subjected to sciatic nerve injury, the number of macrophages and the expression of inflammatory factors in the sciatic nerve were reduced following treatment with the CXCR2 inhibitor SB225002. Simultaneously, we evaluated the sciatic nerve function index, the expression of p75 neurotrophic factor receptor (p75NTR), and myelin proteins, and all of these results were improved with the use of SB225002. Thus, our results suggest that after sciatic nerve injury, the CXCL1-CXCR2 axis mediates the inflammatory response by promoting the recruitment and activation of macrophages, which is detrimental to the repair of the injured nerves. In contrast, treatment with SB225002 promotes the repair of injured sciatic nerves.

A Dynamically Stable Mixed Conducting Interphase for All-Solid-State Lithium Metal Batteries.

All-solid-state lithium (Li) metal batteries (ASSLMBs) employing sulfide solid electrolytes have attracted increasing attention owing to superior safety and high energy density. However, the instability of sulfide electrolytes against Li metal induces the formation of two types of incompetent interphases, solid electrolyte interphase (SEI) and mixed conducting interphase (MCI), which significantly blocks rapid Li-ion transport and induces uneven Li deposition and continuous interface degradation. In this contribution, a dynamically stable mixed conducting interphase (S-MCI) is proposed by in situ stress self-limiting reaction to achieve the compatibility of Li metal with composite sulfide electrolytes (Li6 PS5 Cl (LPSCl) and Li10 GeP2 S12 (LGPS)). The rational design of composite electrolytes utilizes the expansion stress induced by the electrolyte decomposition to in turn constrain the further decomposition of LGPS. Consequently, the S-MCI inherits the high dynamical stability of LPSCl-derived SEI and the lithiophilic affinity of Li-Ge alloy in LGPS-derived MCI. The Li||Li symmetric cells with the protection of S-MCI can operate stably for 1500 h at 0.5 mA cm-2 and 0.5 mAh cm-2 . The Li||NCM622 full cells present stable cycling for 100 cycles at 0.1 C with a high-capacity retention of 93.7%. This work sheds fresh insight into constructing electrochemically stable interphase for high-performance ASSLMBs.

Pathogenic Th17 cell-mediated liver fibrosis contributes to resistance to PD-L1 antibody immunotherapy in hepatocellular carcinoma.

Understanding the mechanisms of resistance of hepatocellular carcinoma (HCC) to targeted therapies and immune checkpoint blockade is critical for the development of new combination therapies and improving patient survival. Here, we found that in HCC, anti-programmed cell death 1 ligand 1 (PD-L1) therapy reduces liver cancer growth, but the tumors eventually become resistant to continued therapy. Experimental analyses shows that the infiltration of pathogenic T helper 17 (pTh17) cells increases in drug-resistant HCC, and pTh17 cells secrete interleukin-17A (IL-17A), which promotes the expression of PD-L1 on the surface of HCC cells and produces resistance to anti-PD-L1 therapy. Anti-IL-17A combined with PD-L1 blockade significantly increased the infiltration of cytotoxic CD8+ T cells expressing high levels of interferon-γ and reduced treatment resistance in HCC. These results support the combination of anti-PD-L1 and anti-IL-17A as a novel strategy to induce effective T cell-mediated anti-tumor immune responses.

The protective effect of erythropoietin and its novel derived peptides in peripheral nerve injury.

Peripheral nerve injury seriously endangers human life and health, but there is no clinical drug for the treatment of peripheral nerve injury, so it is imperative to develop drugs to promote the repair of peripheral nerve injury. Erythropoietin (EPO) not only has the traditional role of promoting erythropoiesis, but also has a tissue-protective effect. Over the past few decades, researchers have confirmed that EPO has neuroprotective effects. However, side effects caused by long-term use of EPO limited its clinical application. Therefore, EPO derivatives with low side effects have been explored. Among them, ARA290 has shown significant protective effects on the nervous system, but the biggest disadvantage of ARA290, its short half-life, limits its application. To address the short half-life issue, the researchers modified ARA290 with thioether cyclization to generate a thioether cyclized helical B peptide (CHBP). ARA290 and CHBP have promising applications as peptide drugs. The neuroprotective effects they exhibit have attracted continuous exploration of their mechanisms of action. This article will review the research on the role of EPO, ARA290 and CHBP in the nervous system around this developmental process, and provide a certain reference for the subsequent research.

Dual polarization-enabled ultrafast bulk photovoltaic response in van der Waals heterostructures.

The bulk photovoltaic effect (BPVE) originating from spontaneous charge polarizations can reach high conversion efficiency exceeding the Shockley-Queisser limit. Emerging van der Waals (vdW) heterostructures provide the ideal platform for BPVE due to interfacial interactions naturally breaking the crystal symmetries of the individual constituents and thus inducing charge polarizations. Here, we show an approach to obtain ultrafast BPVE by taking advantage of dual interfacial polarizations in vdW heterostructures. While the in-plane polarization gives rise to the BPVE in the overlayer, the charge carrier transfer assisted by the out-of-plane polarization further accelerates the interlayer electronic transport and enhances the BPVE. We illustrate the concept in MoS2/black phosphorus heterostructures, where the experimentally observed intrinsic BPVE response time achieves 26 ps, orders of magnitude faster than that of conventional non-centrosymmetric materials. Moreover, the heterostructure device possesses an extrinsic response time of approximately 2.2 ns and a bulk photovoltaic coefficient of 0.6 V-1, which is among the highest values for vdW BPV devices reported so far. Our study thus points to an effective way of designing ultrafast BPVE for high-speed photodetection.

Green technologies behind the Beijing 2022 Olympic and Paralympic winter games.

•The advanced technologies of the first carbon-neutral Olympic Games are introduced.•Successful application experience of each technology is introduced.•This correspondence is conducive to the promotion and application of technologies.