Research on High Performance Methane Gas Concentration Sensor Based on Pyramid Beam Splitter Matrix.

Methane gas concentration detection faces the challenges of increasing accuracy and sensitivity, as well as high reliability in harsh environments. The special design of the optical path structure of the sensitive element provides an opportunity to improve methane gas concentration detection. In this study, the optical path structure of the sensitive element was newly designed based on the Pyramidal beam splitter matrix. The infrared light source was modulated by multi-frequency point-signal superimposed modulation technology. At the same time, concentration detection results and confidence levels were calculated using the four-channel methane gas concentration detection algorithm based on spectral refinement. Through the experiment, it was found that the sensor enables the full-range measurement of CH4; at the lower explosive limit (LEL, CH4 LEL of 5%), the reliability level is 0.01 parts-per-million (PPM), and the limit of detection is 0.5 ppm. The sensor is still capable of achieving PPM-level detections under extreme conditions in which the sensor's optical window is covered by two-thirds and humidity is 85% or dust concentration is 100 mg/m3. Those improve the sensitivity, robustness, reliability, and accuracy of the sensor.

A Capacitive Particle-Analyzing Smoke Detector for Very Early Fire Detection.

Smoke detectors face the challenges of increasing accuracy, sensitivity, and high reliability in complex use environments to ensure the timeliness, accuracy, and reliability of very early fire detection. The improvement in and innovation of the principle and algorithm of smoke particle concentration detection provide an opportunity for the performance improvement in the detector. This study is a new refinement of the smoke concentration detection principle based on capacitive detection of cell structures, and detection signals are processed by a multiscale smoke particle concentration detection algorithm to calculate particle concentration. Through experiments, it is found that the detector provides effective detection of smoke particle concentrations ranging from 0 to 10% obs/m; moreover, the detector can detect smoke particles at parts per million (PPM) concentration levels (at 2 and 5 PPM), and the accuracy of the detector can reach at least the 0.5 PPM level. Furthermore, the detector can detect smoke particle concentrations at better than 1 PPM accuracy even in an environment with 6% obs/m oil gas particles, 7% obs/m large dust interference particles, or 8% obs/m small dust interference particles.

Transition Metal Phosphides: The Rising Star of Lithium-Sulfur Battery Cathode Host.

Lithium-sulfur batteries (LSBs) with ultra-high energy density (2600 W h kg-1 ) and readily available raw materials are emerging as a potential alternative device with low cost for lithium-ion batteries. However, the insulation of sulfur and the unavoidable shuttle effect leads to slow reaction kinetics of LSBs, which in turn cause various roadblocks including poor rate capability, inferior cycling stability, and low coulombic efficiency. The most effective way to solve the issues mentioned above is to rationally design and control the synthesis of the cathode host for LSBs. Transition metal phosphides (TMPs) with good electrical conductivity and dual adsorption-conversion capabilities for polysulfide (PS) are regarded as promising cathode hosts for new-generation LSBs. In this review, the main obstacles to commercializing the LSBs and the development processes of their cathode host are first elaborated. Then, the sulfur fixation principles, and synthesis methods of the TMPs are briefly summarized and the recent progress of TMPs in LSBs is reviewed in detail. Finally, a perspective on the future research directions of LSBs is provided.

Advanced Electrolyte Design for High-Energy-Density Li-Metal Batteries under Practical Conditions.

Given the limitations inherent in current intercalation-based Li-ion batteries, much research attention has focused on potential successors to Li-ion batteries such as lithium-sulfur (Li-S) batteries and lithium-oxygen (Li-O2 ) batteries. In order to realize the potential of these batteries, the use of metallic lithium as the anode is essential. However, there are severe safety hazards associated with the growth of Li dendrites, and the formation of "dead Li" during cycles leads to the inevitable loss of active Li, which in the end is undoubtedly detrimental to the actual energy density of Li-metal batteries. For Li-metal batteries under practical conditions, a low negative/positive ratio (N/P ratio), a electrolyte/cathode ratio (E/C ratio) along with a high-voltage cathode is prerequisite. In this Review, we summarize the development of new electrolyte systems for Li-metal batteries under practical conditions, revisit the design criteria of advanced electrolytes for practical Li-metal batteries and provide perspectives on future development of electrolytes for practical Li-metal batteries.

A Promising High-Voltage Cathode Material Based on Mesoporous Na3 V2 (PO4 )3 /C for Rechargeable Magnesium Batteries.

The lack of suitable high-voltage cathode materials has hindered the development of rechargeable magnesium batteries (RMBs). Here, mesoporous Na3 V2 (PO4 )3 /C (NVP/C) spheres have been synthesized through a facile spray-drying-annealing method, and their electrochemically desodiated phase NaV2 (PO4 )3 /C (ED-NVP/C) has been investigated as an intercalation host for Mg2+ ions. The obtained ED-NVP/C exhibits an average discharge voltage of around 2.5 V (vs. Mg2+ /Mg), higher than those of most previously reported cathode materials. In addition, it can deliver an initial discharge capacity of 88.8 mA h g-1 at 20 mA g-1 , with good cycling stability. Ex situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results demonstrate that the electrochemical reaction is based on an intercalation mechanism and shows good reversibility. Galvanostatic intermittent titration technique (GITT) data have revealed that the intercalation process involves a two-phase transition. The reported ED-NVP/C cathode material with high working voltage offers promising potential for application in RMBs.

Research on high performance combustible gas concentration sensor based on pyramid beam splitter matrix.

Combustible gas concentration detection faces challenges of increasing accuracy, and sensitivity, as well as high reliability in harsh using environments. The special design of the optical path structure of the sensitive element provides an opportunity to improve combustible gas concentration detection. In this study, the optical path structure of the sensitive element was newly designed based on the Pyramidal beam splitter matrix. The infrared light source was modulated by multi-frequency point signal superimposed modulation technology. At the same time, concentration detection results and confidence levels were calculated using the 4-channel combustible gas concentration detection algorithm based on spectral refinement. Through experiment, it is found that the sensor enables full-range measurement of CH4, at the lower explosive limit (LEL, CH4 LEL of 5%), the reliability level is 0.01 parts-per-million (PPM), and the sensor sensitivity is up to 0.5PPM. The sensor is still capable of achieving PPM-level detections, under extreme conditions in which the sensor's optical window is covered by 2/3, and humidity is 85% or dust concentration is 100mg/m3. Those improve the sensitivity, robustness, reliability, and accuracy of the sensor.

Research on a capacitive particle analysis smoke detector.

Smoke detectors face the challenges of increasing accuracy, sensitivity, and high reliability in complex use environments to ensure the timeliness, accuracy, and reliability of very early fire detection. The improvement and innovation of the principle and algorithm for smoke particle concentration detection provide opportunities for improving the performance of the detector. This study represents a new refinement of the smoke concentration detection principle based on capacitive detection of cell structures, and detection signals are processed by a multiscale smoke particle concentration detection algorithm to calculate smoke concentration. Through experiments, it was found that the detector provides effective detection of smoke particle concentrations ranging from 0 to 10% obs/m; moreover, when the detection accuracy is greater than a certain number of parts per million (PPM), the sensitivity of the detector can reach the PPM level; furthermore, the detector can detect smoke particle concentrations higher than the PPM level accuracy even in an environment with a certain concentration of petroliferous and dust particles of different sizes.

Ligustroflavone exerts neuroprotective activity through suppression of NLRP1 inflammasome in ischaemic stroke mice.

Inflammation is thought to play an important role in the pathophysiology of ischaemic stroke, which is a main cause of disability and morbidity worldwide. Inhibition of the NOD-like receptor protein 1 (NLRP1) inflammasome has been reported to alleviate the inflammatory response in cell and animal models. Ligustroflavone (LIG) is a compound derived from Ligustrum lucidum, which shows anti-inflammatory activity and may play a beneficial role in a number of neurological diseases. To date, the potential for LIG to act through NLRP1 as a treatment for ischemic stroke has not been studied. The present study established an ischaemic stroke model by middle cerebral artery occlusion (MCAO). Modified neurological severity scoring, open-field and the Rotarod test were used to assess neurological deficits. Staining with Hoechst 33258 and western blotting were used to evaluate neuronal damage. Expression levels of NLRP1 inflammasome complexes and inflammatory cytokines were determined using western blotting, enzyme-linked immunosorbent assay and reverse transcription-quantitative PCR. Treatment with LIG minimized the impairment of neurological function and blocked neuronal damage in MCAO mice. In addition, treatment with LIG attenuated the upregulation of expression levels of the NLRP1 inflammasome complexes and the inflammatory cytokines TNF-α, IL-18, IL-6 and IL-1ß. Overall, LIG played an important role in anti-inflammatory and neuroprotective activity in MCAO models of ischaemic stroke.

Research Progress on Multifunctional Modified Separator for Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are recognized as one of the second-generation electrochemical energy storage systems with the most potential due to their high theoretical specific capacity of the sulfur cathode (1675 mAhg-1), abundant elemental sulfur energy storage, low price, and green friendliness. However, the shuttle effect of polysulfides results in the passivation of the lithium metal anode, resulting in a decrease in battery capacity, Coulombic efficiency, and cycle stability, which seriously restricts the commercialization of LSBs. Starting from the separator layer before the positive sulfur cathode and lithium metal anode, introducing a barrier layer for the shuttle of polysulfides is considered an extremely effective research strategy. These research strategies are effective in alleviating the shuttle of polysulfide ions, improving the utilization of active materials, enhancing the battery cycle stability, and prolonging the cycle life. This paper reviews the research progress of the separator functionalization in LSBs in recent years and the research trend of separator functionalization in the future is predicted.

Integrative mRNA and Long Noncoding RNA Analysis Reveals the Regulatory Network of Floral Bud Induction in Longan (Dimocarpus longan Lour.).

Longan (Dimocarpus longan Lour.) is a tropical/subtropical fruit tree of significant economic importance. Floral induction is an essential process for longan flowering and plays decisive effects on the longan yield. Due to the instability of flowering, it is necessary to understand the molecular mechanisms of floral induction in longan. In this study, mRNA and long noncoding RNA (lncRNA) transcriptome sequencing were performed using the apical buds of fruiting branches as materials. A total of 7,221 differential expressions of mRNAs (DEmRNAs) and 3,238 differential expressions of lncRNAs (DElncRNAs) were identified, respectively. KEGG enrichment analysis of DEmRNAs highlighted the importance of starch and sucrose metabolic, circadian rhythms, and plant hormone signal transduction pathways during floral induction. Combining the analysis of weighted gene co-expression network (WGCNA) and expression pattern of DEmRNAs in the three pathways, specific transcriptional characteristics at each stage during floral induction and regulatory network involving co-expressed genes were investigated. The results showed that sucrose metabolism and auxin signal transduction may be crucial for the growth and maturity of autumn shoots in September and October (B1-B2 stage); starch and sucrose metabolic, circadian rhythms, and plant hormone signal transduction pathways participated in the regulation of floral bud physiological differentiation together in November and December (B3-B4 stage) and the crosstalk among three pathways was also found. Hub genes in the co-expression network and key DEmRNAs in three pathways were identified. The circadian rhythm genes FKF1 and GI were found to activate SOC1gene through the photoperiod core factor COL genes, and they were co-expressed with auxin, gibberellin, abscisic acid, ethylene signaling genes, and sucrose biosynthesis genes at B4 stage. A total of 12 hub-DElncRNAs had potential for positively affecting their distant target genes in three putative key pathways, predominantly in a co-transcriptional manner. A hypothetical model of regulatory pathways and key genes and lncRNAs during floral bud induction in longan was proposed finally. Our studies will provide valuable clues and information to help elucidate the potential molecular mechanisms of floral initiation in longan and woody fruit trees.

A multifunctional Cu6Sn5 interface layer for dendritic-free lithium metal anode.

The unstable electrode/electrolyte interface of the lithium metal anode is one of the reasons that induce the formation of lithium (Li) dendrites. The Li dendrites will reduce the coulombic efficiency, and even pierce the separator to cause the safety problems. Herein, a tightly bonded and uniformly distributed Cu6Sn5 interface layer is formed on the surface of the Cu foam by a simple electroless plating method. The composite layer has multiple functions, such as high lithiophilicity, high carrier transport and high adaptability to mechanical strain. Based on the versatility of the Cu6Sn5 interface layer, the cycle life of Cu foam is increased from 150 h to 1000 h, and the deposition overpotential is as low as 18 mV. In-situ online observation proves that the existence of composite layer can make Li metal uniformly deposited to avoid the dendrites. Furthermore, Cu6Sn5@Cu foam also shows a higher capacity retention rate (increased from 65.2% to 78.6% after 300 cycles) and a more stable rate performance when it is used in full batteries. Compared with the single function improvement strategy proposed by the current lithium metal anode research. The Cu6Sn5 multifunctional composite layer modification method in this work provides a new strategy for constructing a stable electrode/electrolyte interface.

Tiny Ni Nanoparticles Embedded in Boron- and Nitrogen-Codoped Porous Carbon Nanowires for High-Efficiency Water Splitting.

The integration of nickel (Ni) nanoparticle (NP)-embedded carbon layers (Ni@C) into the three-dimensional (3D) hierarchically porous carbon architectures, where ultrahigh boron (B) and nitrogen (N) doping is a potential methodology for boosting Ni catalysts' water splitting performances, was achieved. In this study, the novel 3D ultrafine Ni NP-embedded and B- and N-codoped hierarchically porous carbon nanowires (denoted as Ni@BNPCFs) were successfully synthesized via pyrolysis of the corresponding 3D nickel acetate [Ni(AC)2·4H2O]-hydroxybenzeneboronic acid-polyvinylpyrrolidone precursor networks woven by electrospinning. After optimizing the pyrolysis temperatures, various structural and morphological characterization analyses indicate that the optimal Ni@BNPCFs-900 networks own a large surface area, abundant micro/mesopores, and vast carbon edges/defects, which boost doping a large amount of B (5.81 atom %) and N (5.84 atom %) dopants into carbon frameworks with 6.36 atom % of BC3, pyridinic-N (pyridinic-N-Ni), and graphitic-N active sites. Electrochemical measurements demonstrate that Ni@BNPCFs-900 reveals the best hydrogen evolution reaction (HER) and oxygen reduction reaction catalytic activities in an alkaline solution. The HER potential at 10 mA cm-2 [E10 = -164.2 mV vs reversible hydrogen electrode (RHE)] of the optimal Ni@BNPCFs-900 is just 96.2 mV more negative than that of the state-of-the-art 20 wt % Pt/C (E10 = -68 mV vs RHE). In particular, the OER E10 and Tafel slope of the optimal Ni@BNPCFs-900 (1.517 V vs RHE and 19.31 mV dec-1) are much smaller than those of RuO2 (1.557 V vs RHE and 64.03 mV dec-1). For full water splitting, the catalytic current density achieves 10 mA cm-2 at a low cell voltage of 1.584 V for the (-) Ni@BNPCFs-900||Ni@BNPCFs-900 (+) electrolysis cell, which is 10 mV smaller than that of the (-) 20 wt % Pt/C||RuO2 (+) benchmark (1.594 V) under the same conditions. The synergistic effects of 3D hierarchically porous structures, advanced charge transport ability, and abundant active centers [such as Ni@BNC, BC3, pyridinic-N (pyridinic-N-Ni), and graphitic-N] are responsible for the excellent water-splitting catalytic activity of the Ni@BNPCFs-900 networks. Especially, because of the remarkable structural and chemical stabilities of 3D hierarchically porous Ni@BNPCFs-900 networks, the (-) Ni@BNPCFs-900||Ni@BNPCFs-900 (+) water electrolysis cell displays an excellent stability.

Sinomenine activation of Nrf2 signaling prevents inflammation and cerebral injury in a mouse model of ischemic stroke.

Sinomenine (SINO), which is used clinically to treat rheumatoid arthritis and neuralgia, is derived from the root and stems of Sinomenium acutum. SINO has been reported to exert analgesic, sedative and anti-inflammatory effects, and provides a protective role against shock and organ damage. Studies have suggested that SINO primarily exerts it anti-inflammatory function by inhibiting NF-κB signaling. There is also evidence to indicate that SINO may regulate inflammation Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling. The present study aimed to investigate whether the anti-inflammatory and cerebral protective effects of SINO were induced through Nrf2 both in vitro and in vivo. The results revealed that SINO significantly upregulated Nrf2 protein expression levels, increased Nrf2 nuclear translocation and the upregulated the protein expression levels of downstream factors. The treatment of a middle cerebral artery occlusion model mice with SINO effectively reduced cerebral damage and inflammation, and restored the balance in cerebral oxidative stress. In addition, SINO treatment also promoted Nrf2-dependent microglia M1/M2 polarization and inhibited the phosphorylation of IκBα as well as NF-κB nuclear translocation. This revealed an important upstream event that contributed to its anti-inflammatory and cerebral tissue protective effects. In conclusion, the findings of the present study identified a novel pathway through which SINO may exert its anti-inflammatory and cerebral protective functions, and provided a molecular basis for the potential applications of SINO in the treatment of cerebral inflammatory disorders.

Pt3Ni@C Composite Material Designed and Prepared Based on Volcanic Catalytic Curve and Its High-Performance Static Lithium Polysulfide Semiliquid Battery.

There are many challenges for the Static lithium polysulfide semiliquid battery in its commercial application, such as poor stability of the cathode material and further amplification of the lithium polysulfide shuttle effect. Therefore, this manuscript introduced a new type of Pt3Ni@C composite material as cathode working electrode based on the principle of volcanic catalytic curve. Through symmetric battery test, CV, polarization curves and impedance test, it was found that Pt3Ni@C composite material had good catalytic activity of lithium polysulfide to improve electrochemical kinetics. When the catholyte was Li2S8 and the charge-discharge voltage range was 1.8~2.6 V, the capacity maintained at approximately 550 mAh g-1, and the coulombic efficiency maintained at approximately 95% after 100 cycles at a current rate of 0.5 mA cm-2. The Pt3Ni@C composite material is a potential cathode material with the specific capacity and long cycling stability of the static lithium polysulfide semiliquid battery.

Genome-Wide Identification and Expression Analysis of Auxin Response Factor (ARF) Gene Family in Longan (Dimocarpus longan L.).

Auxin response factor (ARF) is the key regulator involved in plant development. Despite their physiological importance identified in various woody plants, the functions of ARF genes in longan were still not clear. In this study, 17 longan ARF genes (DlARF) were identified using the reference longan genome data. According to the phylogenetic relationships among longan, Arabidopsis and apple, DlARFs were divided into four classes. Most DlARFs showed a closer relationship with ARFs from apple than those from Arabidopsis. The analysis of gene structure and domain revealed high similarity of different ARF genes in the same class. Typical features of B3-type DNA binding domain (DBD) motif, Auxin Resp motifs, and a highly conserved C-terminal Phox and Bem1 (PB1) domain were present in all DlARFs except for DlARF-2,-3,-13 which lacked PBI domain. Expression profiles of 17 DlARF genes in longan different tissues showed that some DlARF genes were tissues-specific genes. Analysis of three longan transcriptomes showed seven DlARFs (DlARF-1,-2,-6,-8,-9,-11,-16) had higher expression levels during floral bud differentiation of common longan and in the buds of 'Sijimi', suggesting these genes may promote floral bud differentiation in longan. Further qPCR analysis showed that among seven DlARF genes, the expression levels of DlARF-2,-6,-11,-16 increased significantly during the physiological differentiation stage of longan floral buds, confirming that they may play a role in flowering induction. Promoter sequence analysis revealed cis-elements related to flowering induction such as low-temperature responsiveness motif and circadian control motif. Motifs linked with hormone response for instance Auxin, MeJA, Gibberellin, and Abscisic acid were also found in promoters. This study provides a comprehensive overview of the ARF gene family in longan. Our findings could provide new insights into the complexity of the regulation of ARFs at the transcription level that may be useful to develop breeding strategies to improve development or promote flowering in longan.

Control of Laves Precipitation in a FeCrAl-based Alloy Through Severe Thermomechanical Processing.

In recent years, the development of nuclear grade FeCrAl-based alloys with enhanced accident tolerance has been carried out for light water reactor (LWR) fuel cladding to serve as a substitute for zirconium-based alloys. To achieve excellent microstructure stability and mechanical properties, the control of precipitation particles is critical for application of FeCrAl-based alloys. In this paper, the effect of thermomechanical processing on the microstructure and precipitation behavior of hot-rolled FeCrAl alloy plates was examined. After hot rolling, the FeCrAl alloy plates had typical deformation textures. The rolling direction (RD) orientation gradually rotated from <100> to <110> along with increasing reduction. Shear bands and cell structures were formed in the matrix, and the former acted as preferable nucleation sites for crystallization. Improved deformation helped to produce strain-induced precipitation. The plate with 83% reduction had the most homogeneous and finest precipitation particles. Identification results by TEM indicated that the Laves precipitation was of the Fe2Nb-type crystal structure type, with impurities including Mo, Cr, and Si. The plate with uniform Laves particles displayed favorable heat stability after a long period of aging at 800 °C. The microstructure evolution of the aged sample was also observed. The deformation microstructure and the strain-induced precipitation mechanism of FeCrAl alloys are discussed.

Ion Irradiation-Induced Microstructural Evolution of Ni⁻Mo⁻Cr Low Alloy Steels.

As leading candidates of sheet steels for advanced nuclear reactors, three types of Ni⁻Mo⁻Cr high-strength low alloy (HSLA) steels named as CNST1, CNST2 and CNSS3 were irradiated by 400 keV Fe⁺ with peak fluence to 1.4 × 1014, 3.5 × 1014 and 7.0 × 1014 ions/cm², respectively. The distribution and morphology of the defects induced by the sample preparation method and Fe⁺ irradiation dose were investigated by transmission electron microscopy (TEM) and positron-annihilation spectroscopy (PAS). TEM samples were prepared with two methods, i.e., a focused ion beam (FIB) technique and the electroplating and twin-jet electropolishing (ETE) method. Point defects and dislocation loops were observed in CNST1, CNST2 and CNSS3 samples prepared via FIB. On the other hand, samples prepared via the ETE method revealed that a smaller number of defects was observed in CNST1, CNST2 and almost no defects were observed in CNST3. It is indicated that artifact defects could be introduced by FIB preparation. The PAS S-W plots showed that the existence of two types of defects after ion implantation included small-scale defects such as vacancies, vacancy clusters, dislocation loops and large-sized defects. The S parameter of irradiated steels showed a clear saturation in PAS response with increasing Fe⁺ dose. At the same irradiation dose, higher values of the S-parameter were achieved in CNST1 and CNST2 samples when compared to that in CNSS3 samples. The mechanism and evolution behavior of irradiation-induced defects were analyzed and discussed.

Investigation of the Na Storage Property of One-Dimensional Cu2- xSe Nanorods.

In this study, one-dimensional Cu2- xSe nanorods synthesized by a simple water evaporation-induced self-assembly approach are served as the anode material for Na-ion batteries for the first time. Cu2- xSe electrodes express outstanding electrochemical properties. The initial discharge capacity is 149.3 mA h g-1 at a current density of 100 mA g-1, and the discharge capacity can remain at 106.2 mA h g-1 after 400 cycles. Even at a high current density of 2000 mA g-1, the discharge capacity of the Cu2- xSe electrode still remains at 62.8 mA h g-1, showing excellent rate performance. Owing to the excellent electronic conductivity and one-dimensional structure of Cu2- xSe, the Cu2- xSe electrodes manifest fast Na+ ion diffusion rate. Moreover, detailed Na+ insertion/extraction mechanism is further investigated by ex situ measurements and theoretical calculations.

Directly Coating a Multifunctional Interlayer on the Cathode via Electrospinning for Advanced Lithium-Sulfur Batteries.

The lithium-sulfur battery is considered as a prospective candidate for a high-energy-storage system because of its high theoretical specific capacity and energy. However, the dissolution and shutter of polysulfides lead to low active material utilization and fast capacity fading. Electrospinning technology is employed to directly coat an interlayer composed of polyacrylonitrile (PAN) and nitrogen-doped carbon black (NC) fibers on the cathode. Benefiting from electrospinning technology, the PAN-NC fibers possess good electrolyte infiltration for fast lithium-ion transport and great flexibility for adhering on the cathode. The NC particles provide good affinity for polysufides and great conductivity. Thus, the polysulfides can be trapped on the cathode and reutilized well. As a result, the PAN-NC-coated sulfur cathode (PAN-NC@cathode) exhibits the initial discharge capacity of 1279 mAh g-1 and maintains the reversible capacity of 1030 mAh g-1 with capacity fading of 0.05% per cycle at 200 mA g-1 after 100 cycles. Adopting electrospinning to directly form fibers on the cathode shows a promising application.

Facile Synthesis of Rod-like Cu2-x Se and Insight into its Improved Lithium-Storage Property.

A rod-like Cu2-x Se is synthesized by a facile water evaporation process. The electrochemical reaction mechanism is investigated by ex situ X-ray diffraction (XRD). By adopting an ether-based electrolyte instead of a carbonate-based electrolyte, the electrochemical performance of Cu2-x Se electrodes improved significantly. The Cu2-x Se electrodes exhibit outstanding cycle performance: after 1000 cycles, 160 mA h g-1 can be maintained with a retention of 80.3 %. At current densities of 100, 200, 500, and 1000 mA g-1 , the capacity of a Cu2-x Se/Li battery was 208, 202, 200, and 198 mA h g-1 , respectively, showing excellent rate capability. The 4-probe conductivity measurements along with electrochemical impendence spectroscopy (EIS) and cyclic voltammetry (CV) tests illustrate that the Cu2-x Se electrodes display high specific conductivity and impressive lithium-ion diffusion rate, which makes the Cu2-x Se a promising anode material for lithium-ion batteries.