Dual-Site Doping in Transition Metal Oxide Cathode Enables High-Voltage Stability of Na-Ion Batteries.

Designing cathode materials that effectively enhancing structural stability under high voltage is paramount for rationally enhancing energy density and safety of Na-ion batteries. This study introduces a novel P2-Na0.73K0.03Ni0.23Li0.1Mn0.67O2 (KLi-NaNMO) cathode through dual-site synergistic doping of K and Li in Na and transition metal (TM) layers. Combining theoretical and experimental studies, this study discovers that Li doping significantly strengthens the orbital overlap of Ni (3d) and O (2p) near the Fermi level, thereby regulates the phase transition and charge compensation processes with synchronized Ni and O redox. The introduction of K further adjusts the ratio of Nae and Naf sites at Na layer with enhanced structural stability and extended lattice space distance, enabling the suppression of TM dissolution, achieving a single-phase transition reaction even at a high voltage of 4.4 V, and improving reaction kinetics. Consequently, KLi-NaNMO exhibits a high capacity (105 and 120 mAh g-1 in the voltage of 2-4.2 V and 2-4.4 V at 0.1 C, respectively) and outstanding cycling performance over 300 cycles under 4.2 and 4.4 V. This work provides a dual-site doping strategy to employ synchronized TM and O redox with improved capacity and high structural stability via electronic and crystal structure modulation.

Association between sleep apnea-specific hypoxic burden and severity of coronary artery disease.

PURPOSE: Sleep apnea-specific hypoxic burden (SASHB) is a polysomnographic metric that comprehensively measures the degree of nocturnal desaturation caused by obstructive sleep apnea. This research was conducted to elucidate the relationship between SASHB and coronary artery disease (CAD) severity. METHODS: We carried out a prospective study of hospitalized patients with CAD of unstable angina who were expected to undergo invasive coronary angiography at Beijing Anzhen Hospital from February to September 2023. SASHB values were calculated using a self-programmed C + + program. Multivariable logistic regression analysis was applied to identify the association between SASHB and the prevalence of severe CAD, documented by the Gensini Score, and the SYNTAX (Synergy between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) Score. RESULTS: This study enrolled 137 patients with a median age of 59 years, 96 (70.1%) of whom were male. A total of 125 (91.2%) patients had coronary stenosis of ≥ 50% in at least one location. Patients with a high SASHB of ≥ 18% min/h had a significantly higher Gensini Score (32.0 vs. 18.5, P = 0.002) and SYNTAX Score (14.0 vs. 7.0, P = 0.002) than those with a low SASHB. After adjusting for multiple covariates, a high SASHB was significantly associated with the prevalence of severe CAD, determined by a Gensini Score ≥ 21 (OR 2.67, P = 0.008) or a SYNTAX Score > 22 (OR 4.03, P = 0.016). CONCLUSION: Our findings revealed a robust and independent association between SASHB and CAD severity in patients with unstable angina, highlighting the potential value of SASHB as a predictor of risk and a target for interventions aimed at preventing cardiovascular diseases. TRIAL REGISTRATION: Chinese Clinical Trial Registry No. ChiCTR2300067991 on February 2, 2023.

Regulating the Wettability of Hard Carbon through Open Mesochannels for Enhanced K+ Storage.

Hard carbons are deemed as promising anode materials for high-performance potassium-ion battery, but their commercialization is still hindered by the insufficient K+ transfer kinetics and poor potassiophilicity. Herein, these issues are addressed by improving the wettability of hard carbon, which can be achieved by the introduction of open mesochannels. A series of such hollow mesoporous carbon capsules with different dimensions are synthesized, which exhibit markedly enhanced wettability with electrolyte compared to the microporous counterparts. Various characterizations confirm its effects on promoting the kinetics and potassiophilicity of as-synthesized carbons, which can be additionally improved by S-doping. As a result, the 2D mesoporous carbon anode exhibits excellent rate capability (122.2 mAh g-1 at 4 A g-1 ), high reversible capacity (396.6 mAh g-1 at 0.1 A g-1 after 200 cycles), and outstanding cycling stability (197.0 mAh g-1 at 2 A g-1 after 1400 cycles). In addition, the hollow mesoporous architecture can effectively buffer the volume expansion and thus stabilize the carbon anodes, as visualized by in situ transmission electron microscopy. This work provides new insight for enhanced K+ storage performance from the perspective of anode wettability with electrolyte, as well as a universal anode design that combines mesochannels architecture with heteroatom doping.

DOIDS: An Intrusion Detection Scheme Based on DBSCAN for Opportunistic Routing in Underwater Wireless Sensor Networks.

In Underwater Wireless Sensor Networks (UWSNs), data should be transmitted to data centers reliably and efficiently. However, due to the harsh channel conditions, reliable data transmission is a challenge for large-scale UWSNs. Thus, opportunistic routing (OR) protocols with high reliability, strong robustness, low end-to-end delay, and high energy efficiency are widely applied. However, OR in UWSNs is vulnerable to routing attacks. For example, sinkhole attack nodes can attract traffic from surrounding nodes by forging information such as the distance to the sink node. In order to reduce the negative impact of malicious nodes on data transmission, we propose an intrusion detection scheme (IDS) based on the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) clustering algorithm for OR (DOIDS) in this paper. DOIDS is based on small-sample IDS and is suitable for UWSNs with sparse node deployment. In DOIDS, the local monitoring mechanism is adopted. Every node in the network running DOIDS can select the trusted next hop. Firstly, according to the behavior characteristics of common routing attack nodes and unreliable underwater acoustic channel characteristics, DOIDS selected the energy consumption, forwarding, and link quality information of candidate nodes as the detection feature values. Then, the collected feature information is used to detect potential abnormal nodes through the DBSCAN clustering algorithm. Finally, a decision function is defined according to the time decay function to reduce the false detection rate of DOIDS. It makes a final judgment on whether the potential abnormal node is malicious. The simulation results show that the algorithm can effectively improve the detection accuracy rate (3% to 15% for different scenarios) and reduce the false positive rate, respectively.

Enhanced Cyclability of Lithium Metal Anodes Enabled by Anti-aggregation of Lithiophilic Seeds.

Constructing 3D skeletons modified with lithiophilic seeds has proven effective in achieving dendrite-free lithium metal anodes. However, these lithiophilic seeds are mostly alloy- or conversion-type materials, and they tend to aggregate and redistribute during cycling, resulting in the failure of regulating Li deposition. Herein, we address this crucial but long-neglected issue by using intercalation-type lithiophilic seeds, which enable antiaggregation owing to their negligible volume expansion and high electrochemical stability against Li. To exemplify this, a 3D carbon-based host is built, in which ultrafine TiO2 seeds are uniformly embedded in nitrogen-doped hollow porous carbon spheres (N-HPCSs). The TiO2@N-HPCSs electrode exhibits superior Coulombic efficiency, high-rate capability, and long-term stability when evaluated as compertitive anodes for Li metal batteries. Furthermore, the superiority of intercalation-type seeds is comprehensively revealed through controlled experiments by various in situ/ex situ electron and optical microscopies, which highlights the excellent structural stability and lithiophilicity of TiO2 nanoseeds upon repeated cycling.

Assessing Long-Term Cycling Stability of Single-Crystal Versus Polycrystalline Nickel-Rich NCM in Pouch Cells with 6 mAh cm-2 Electrodes.

Lithium-ion batteries based on single-crystal LiNi1- x - y Cox Mny O2 (NCM, 1-x-y ≥ 0.6) cathode materials are gaining increasing attention due to their improved structural stability resulting in superior cycle life compared to batteries based on polycrystalline NCM. However, an in-depth understanding of the less pronounced degradation mechanism of single-crystal NCM is still lacking. Here, a detailed postmortem study is presented, comparing pouch cells with single-crystal versus polycrystalline LiNi0.60 Co0.20 Mn0.20 O2 (NCM622) cathodes after 1375 dis-/charge cycles against graphite anodes. The thickness of the cation-disordered layer forming in the near-surface region of the cathode particles does not differ significantly between single-crystal and polycrystalline particles, while cracking is pronounced for polycrystalline particles, but practically absent for single-crystal particles. Transition metal dissolution as quantified by time-of-flight mass spectrometry on the surface of the cycled graphite anode is much reduced for single-crystal NCM622. Similarly, CO2 gas evolution during the first two cycles as quantified by electrochemical mass spectrometry is much reduced for single-crystal NCM622. Benefitting from these advantages, graphite/single-crystal NMC622 pouch cells are demonstrated with a cathode areal capacity of 6 mAh cm-2 with an excellent capacity retention of 83% after 3000 cycles to 4.2 V, emphasizing the potential of single-crystalline NCM622 as cathode material for next-generation lithium-ion batteries.

Resistive Switching of Individual, Chemically Synthesized TiO2 Nanoparticles.

Resistively switching devices are considered promising for next-generation nonvolatile random-access memories. Today, such memories are fabricated by means of "top-down approaches" applying thin films sandwiched between nanoscaled electrodes. In contrast, this work presents a "bottom-up approach" disclosing for the first time the resistive switching (RS) of individual TiO2 nanoparticles (NPs). The NPs, which have sizes of 80 and 350 nm, respectively, are obtained by wet chemical synthesis and thermally treated under oxidizing or vacuum conditions for crystallization, respectively. These NPs are deposited on a Pt/Ir bottom electrode and individual NPs are electrically characterized by means of a nanomanipulator system in situ, in a scanning electron microscope. While amorphous NPs and calcined NPs reveal no switching hysteresis, a very interesting behavior is found for the vacuum-annealed, crystalline TiO(2-x) NPs. These NPs reveal forming-free RS behavior, dominantly complementary switching (CS) and, to a small degree, bipolar switching (BS) characteristics. In contrast, similarly vacuum-annealed TiO2 thin films grown by atomic layer deposition show standard BS behavior under the same conditions. The interesting CS behavior of the TiO(2-x) NPs is attributed to the formation of a core-shell-like structure by re-oxidation of the reduced NPs as a unique feature.

Volatile resistance states in electrochemical metallization cells enabling non-destructive readout of complementary resistive switches.

Redox-based resistive memory cells exhibit changes of OFF or intermediate resistance values over time and even ON states can be completely lost in certain cases. The stability of these resistance states and the time until resistance loss strongly depends on the materials system. On the basis of electrical measurements and chemical analysis we found a viable explanation for these volatile resistance states (VRSs) in Ag-GeSx-based electrochemical metallization memory cells and identified a technological application in the field of crossbar memories. Complementary resistive switches usually suffer from the necessity of a destructive read-out procedure increasing wear and reducing read-out speed. From our analysis we deduced a solution to use the VRS as an inherent selector mechanism without the need for additional selector devices.

Graphene-Enhanced UV-C LEDs.

Light-emitting diodes in the UV-C spectral range (UV-C LEDs) can potentially replace bulky and toxic mercury lamps in a wide range of applications including sterilization and water purification. Several obstacles still limit the efficiencies of UV-C LEDs. Devices in flip-chip geometry suffer from a huge difference in the work functions between the p-AlGaN and high-reflective Al mirrors, whereas the absence of UV-C transparent current spreading layers limits the development of UV-C LEDs in standard geometry. Here it is demonstrated that transfer-free graphene implemented directly onto the p-AlGaN top layer by a plasma enhanced chemical vapor deposition approach enables highly efficient 275 nm UV-C LEDs in both, flip-chip and standard geometry. In flip-chip geometry, the graphene acts as a contact interlayer between the Al-mirror and the p-AlGaN enabling an external quantum efficiency (EQE) of 9.5% and a wall-plug efficiency (WPE) of 5.5% at 8 V. Graphene combined with a ≈1 nm NiOx support layer allows a turn-on voltage <5 V. In standard geometry graphene acts as a current spreading layer on a length scale up to 1 mm. These top-emitting devices exhibit a EQE of 2.1% at 8.7 V and a WPE of 1.1%.

Inoculation of chromium-tolerant bacterium LBA108 to enhance resistance in radish (Raphanus sativus L.) and combined remediation of chromium-contaminated soil.

Cr(VI) has been a carcinogen for organisms and a hazard to human health throughout the food chain. To explore a cost-effective and efficient method for removing Cr(VI), a Cr-resistant strain named LBA108 was isolated from the soil of a molybdenum-lead mining area. It was identified as Microbacterium through biochemical tests and 16S rDNA sequence analysis. Following 48 hours of incubation in LB culture medium containing 60 mg L-1 Cr(VI), the LBA108 strain exhibited reduction and adsorption rates for Cr(VI) at 96.64% and 15.86%, respectively. The removal mechanism was subsequently confirmed through Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction analysis. In an experimental setup, radish seedlings were cultivated as test crops under varying levels of Cr stress (ranging from 0 to 7 mg L-1) in a hydroponic experiment. With the inoculation of the LBA108 strain, the fresh weight of radish seedlings increased by 2.05 times and plant length increased by 34.5% under 7 mg L-1 Cr stress. In addition, the plant produced more antioxidant enzymes/enhanced antioxidant enzyme activities such as superoxide dismutase and catalase to prevent oxidative stress. Under Cr stress (6 mg L-1), the accumulation of Cr in rhizomes of radish seedlings increased compared to the control group by 91.44%, while the absorption of Cr by leaves decreased by 52.10%. These findings suggest that the LBA108 strain possesses bioremediation capabilities as a microbial-phytoremediation option for Cr-contaminated soil.

Growth of millimeter-sized 2D metal iodide crystals induced by ion-specific preference at water-air interfaces.

Conventional liquid-phase methods lack precise control in synthesizing and processing materials with macroscopic sizes and atomic thicknesses. Water interfaces are ubiquitous and unique in catalyzing many chemical reactions. However, investigations on two-dimensional (2D) materials related to water interfaces remain limited. Here we report the growth of millimeter-sized 2D PbI2 single crystals at the water-air interface. The growth mechanism is based on an inherent ion-specific preference, i.e. iodine and lead ions tend to remain at the water-air interface and in bulk water, respectively. The spontaneous accumulation and in-plane arrangement within the 2D crystal of iodide ions at the water-air interface leads to the unique crystallization of PbI2 as well as other metal iodides. In particular, PbI2 crystals can be customized to specific thicknesses and further transformed into millimeter-sized mono- to few-layer perovskites. Additionally, we have developed water-based techniques, including water-soaking, spin-coating, water-etching, and water-flow-assisted transfer to recycle, thin, pattern, and position PbI2, and subsequently, perovskites. Our water-interface mediated synthesis and processing methods represents a significant advancement in achieving simple, cost-effective, and energy-efficient production of functional materials and their integrated devices.

Persistent Hypoxia with Intermittent Aggravation Causes Imbalance in Smad3/Myocardin-Related Transcription Factor Signaling with Consequent Endothelial Senescence and Pulmonary Arterial Remodeling.

Loss of Smad3 and the consequent activation of myocardin-related transcription factor (MRTF) are associated with vascular pathologies. This study aimed to examine the impact of persistent hypoxia with intermittent aggravation (PI hypoxia) on cellular senescence and pulmonary arterial remodeling mediated by the Smad3/MRTF imbalance. We examined the effects of PI hypoxia on the Smad3/MRTF pathway and cellular senescence using human pulmonary artery endothelial cells (HPAECs) and in vivo studies in rats. The senescent degree was evaluated using ß-galactosidase staining, p16 quantitation and the measurement of senescence-associated secretory phenotype. Structural data in the pathological analysis of pulmonary artery remodeling were collected. Compared to the control, HPAECs and pulmonary tissue from rats exposed to PI hypoxia showed a significantly higher senescent degree, lower expression of Smad3, and higher MRTF levels. The overexpression of Smad3 significantly mitigated HPAECs senescence in vitro. Further, treatment with CCG-203971, which inhibits MRTF, increased Smad3 levels and reduced ß-galactosidase positive cells in rat lung tissue. This intervention also alleviated PI hypoxia-induced pathological changes, including remodeling indices of pulmonary arterial thickening, muscularization, and collagen formation. In conclusion, imbalanced Smad3/MRTF signaling is linked to PI hypoxia-induced senescence and pulmonary arterial remodeling, making it a potential therapeutic target for patients with sleep apnea and chronic obstructive pulmonary disease.

Superfast Mass Transport of Na/K Via Mesochannels for Dendrite-Free Metal Batteries.

Fast ion diffusion in anode hosts enabling uniform distribution of Li/Na/K is essential for achieving dendrite-free alkali-metal batteries. Common strategies, e.g. expanding the interlayer spacing of anode materials, can enhance bulk diffusion of Li but are less efficient for Na and K due to their larger ionic radius. Herein, a universal strategy to drastically improve the mass-transport efficiency of Na/K by introducing open mesochannels in carbon hosts is proposed. Such pore engineering can increase the accessible surface area by one order of magnitude, thus remarkably accelerating surface diffusion, as visualized by in situ transmission electron microscopy. In particular, once the mesochannels are filled by the Na/K metals, they become the superfast channels for mass transport via the mechanism of interfacial diffusion. Thus-modified carbon hosts enable Na/K filling in their inner cavities and uniform deposition across the whole electrodes with fast kinetics. The resulting Na-metal anodes can exhibit stable dendrite-free cycling with outstanding rate performance at a high current density of up to 30 mA cm-2 . This work presents an inspiring attempt to address the sluggish transport issue of Na/K, as well as valuable insights into the mass-transport mechanism in porous anodes for high-performance alkali-metal storage.

Boosting the Sensitivity of WSe2 Phototransistor via Janus Interfaces with 2D Perovskite and Ferroelectric Layers.

Hybrid systems have recently attracted increasing attention, which combine the special attributes of each constitute and create interesting functionalities through multiple heterointerface interactions. Here, we design a two-dimensional (2D) hybrid phototransistor utilizing Janus-interface engineering, in which the WSe2 channel combines light-sensitive perovskite and spontaneously polarized ferroelectrics, achieving collective ultrasensitive detection performance. The top perovskite (BA2(MA)3Pb4I13) layer can absorb the light efficiently and provide generous photoexcited holes to WSe2. WSe2 exhibit p-type semiconducting states of different degrees due to the selective light-operated doping effect, which also enables the ultrahigh photocurrent of the device. The bottom ferroelectric (Hf0.5Zr0.5O2) layer dramatically decreases the dark current, which should be attributed to the ferroelectric polarization assisted charge trapping effect and improved gate control. As a whole, our phototransistors show excellent photoelectric performances across the ultraviolet to near-infrared range (360-1050 nm), including an ultrahigh ON/OFF current ratio > 109 and low noise-equivalent power of 1.3 fW/Hz1/2, all of which are highly competitive in 2D semiconductor-based optoelectronic devices. In particular, the devices show excellent weak light detection ability, where the distinguishable photoswitching signal is obtained even under a record-low light intensity down to 1.6 nW/cm2, while showing a high responsivity of 2.3 × 105 A/W and a specific detectivity of 4.1 × 1014 Jones. Our work demonstrates that Janus-interface design makes the upper and lower interfaces complement each other for the joint advancement into high-performance optoelectronic applications, providing a picture to realize the integrated engineering on carrier dynamics by light irradiation, electric field, interfacial trapping, and band alignment.

Graphene as a Transparent Conductive Electrode in GaN-Based LEDs.

Graphene combines high conductivity (sheet resistance down to a few hundred Ω/sq and even less) with high transparency (>90%) and thus exhibits a huge application potential as a transparent conductive electrode in gallium nitride (GaN)-based light-emitting diodes (LEDs), being an economical alternative to common indium-based solutions. Here, we present an overview of the state-of-the-art graphene-based transparent conductive electrodes in GaN-based LEDs. The focus is placed on the manufacturing progress and the resulting properties of the fabricated devices. Transferred as well as directly grown graphene layers are considered. We discuss the impact of graphene-based transparent conductive electrodes on current spreading and contact resistance, and reveal future challenges and perspectives on the use of graphene in GaN-based LEDs.

Harnessing Plasma-Assisted Doping Engineering to Stabilize Metallic Phase MoSe2 for Fast and Durable Sodium-Ion Storage.

Metallic-phase selenide molybdenum (1T-MoSe2 ) has become a rising star for sodium storage in comparison with its semiconductor phase (2H-MoSe2 ) owing to the intrinsic metallic electronic conductivity and unimpeded Na+ diffusion structure. However, the thermodynamically unstable nature of 1T phase renders it an unprecedented challenge to realize its phase control and stabilization. Herein, a plasma-assisted P-doping-triggered phase-transition engineering is proposed to synthesize stabilized P-doped 1T phase MoSe2 nanoflower composites (P-1T-MoSe2 NFs). Mechanism analysis reveals significantly decreased phase-transition energy barriers of the plasma-induced Se-vacancy-rich MoSe2 from 2H to 1T owing to its low crystallinity and reduced structure stability. The vacancy-rich structure promotes highly concentrated P doping, which manipulates the electronic structure of the MoSe2 and urges its phase transition, acquiring a high transition efficiency of 91% accompanied with ultrahigh phase stability. As a result, the P-1T-MoSe2 NFs deliver an exceptional high reversible capacity of 510.8 mAh g-1 at 50 mA g-1 with no capacity fading over 1000 cycles at 5000 mA g-1 for sodium storage. The underlying mechanism of this phase-transition engineering verified by profound analysis provides informative guide for designing advanced materials for next-generation energy-storage systems.

Cobalt-Catalyzed Carbonization Incorporating Disordered Defects in Ordered Graphitic Domains for Fast and Ultrastable Potassium-Ion Battery.

Carbonaceous materials featuring both ordered graphitic structure and disordered defects hold great promise for high-performance K-ion batteries (KIBs) due to the concurrent advantages of high electronic conductivity, fast and reversible K+ intercalation/deintercalation, and abundant active K+ storage sites. However, it has been a lingering problem and remains a big challenge because graphitization and defects are intrinsic trade-off properties of carbonaceous materials. Herein, for the first time, we propose a cobalt-catalyzed carbonization strategy to fabricate porous carbon nanofibers that incorporate disordered defects in graphitic domain layers (PCNFs-DG) for fast and durable K+ storage. The Co catalyst not only ensures the formation of highly graphitized carbon shells around the Co particles but also introduces nanopores and doping defects in the following catalyst removal process. This idea of architecting defected-ordered graphitic carbon engineering guarantees fast reaction kinetics as well as structural stability with negligible interlayer expansion/contraction owing to the uncompromised electronic conductivity, expanded interlayer spacing, and regulated K+ storage mechanism. These appealing features translate to a high reversible capacity of 318.5 mAh g-1 at 100 mA g-1 and ultrahigh stability with almost 100% capacity retention over 2000 cycles in KIBs. This work puts in perspective that defected and ordered carbonaceous materials could be simultaneously achieved, advancing their performance for next-generation energy storage systems.

Boosting the potassium-ion storage performance enabled by engineering of hierarchical MoSSe nanosheets modified with carbon on porous carbon sphere.

Developing suitable electrode materials capable of tolerating severe structural deformation and overcoming sluggish reaction kinetics resulting from the large radius of potassium ion (K+) insertion is critical for practical applications of potassium-ion batteries (PIBs). Herein, a superior anode material featuring an intriguing hierarchical structure where assembled MoSSe nanosheets are tightly anchored on a highly porous micron-sized carbon sphere and encapsulated within a thin carbon layer (denoted as Cs@MoSSe@C) is reported, which can significantly boost the performance of PIBs. The assembled MoSSe nanosheets with expanded interlayer spacing and rich anion vacancy can facilitate the intercalation/deintercalation of K+ and guarantee abundant active sites together with a low K+ diffusion barrier. Meanwhile, the thin carbon protective layer and the highly porous carbon sphere matrix can alleviate the volume expansion and enhance the charge transport within the composite. Under these merits, the as-prepared Cs@MoSSe@C anode exhibits a high reversible capacity (431.8 mAh g-1 at 0.05 A g-1), good rate capability (161 mAh g-1 at 5 A g-1), and superior cyclic performance (70.5% capacity retention after 600 cycles at 1 A g-1), outperforming most existing Mo-based S/Se anodes. The underlying mechanisms and origins of superior performance are elucidated by a set of correlated in-situ/ex-situ characterizations and theoretical calculations. Further, a PIB full cell based on Cs@MoSSe@C anode also exhibits an impressive electrochemical performance. This work provides some insights into developing high-performance PIBs anodes with transition-metal chalcogenides.

Fast and Durable Potassium Storage Enabled by Constructing Stress-Dispersed Co3Se4 Nanocrystallites Anchored on Graphene Sheets.

Transition metal dichalcogenides are regarded as promising anode materials for potassium-ion batteries (PIBs) because of their high theoretical capacities. However, due to the large atomic radius of K+, the structural damage caused by the huge volume expansion upon potassiation is much more severe than that of their lithium counterparts. In this research, a stress-dispersed structure with Co3Se4 nanocrystallites orderly anchored on graphene sheets is achieved through a two-step hydrothermal treatment to alleviate the structural deterioration. The ability to reduce the contact stress by the well-dispersed Co3Se4 nanocrystallites during K+ intercalation, together with the highly conductive graphene matrix, provides a more reliable and efficient anode architecture than its two agminated counterparts. Given these advantages, the optimized electrode delivers excellent cycling stability (301.8 mA h g-1 after 500 cycles at 1 A g-1), as well as an outstanding rate capacity (203.8 mA h g-1 at 5 A g-1). Further in situ and ex situ characterizations and density functional theory calculations elucidate the potassium storage mechanism of Co3Se4 during the conversion reaction and reveal the fast electrochemical kinetics of the rationally designed electrode. This work provides a practical approach for constructing stable metal-selenide anodes with long cycle life and high-rate performance for PIBs.

Rational Design of Near-Infrared Cyanine-Based Fluorescent Probes for Rapid In Vivo Sensing Cysteine.

Cysteine (Cys) is well-known to be an important biothiol and related to many diseases. However, the in situ trapping of endogenous Cys is still handicapped by a lack of straightforward methods combined with long-wavelength emission and high-performance response. In this work, we described the rational design strategy of cyanine-based near-infrared (NIR) probes for the rapid detection of mitochondrial Cys in living cells and mice. We focus on how to improve the response rate via regulating the electron density of the recognition units in probes. The obtained three probes all displayed remarkable fluorescence enhancement at 780 nm. From screening the obtained probes, it was found that the probe Cy-S-diOMe with electron-donating recognition unit displayed the fastest response rate, the lowest detection limit, and the highest signal-to-noise ratio. More importantly, Cy-S-diOMe was successfully applied to monitor Cys in tumor-bearing mice (within merely 5 min). This paradigm by modulation of the response rate in the cyanine dyes provides a promising methodology for the design of high-performance cyanine-based NIR probes.