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LiNi0.8Co0.1Mn0.1O2 cathode material for lithium-ion battery exhibits high capacity, but it suffers from interfacial side reactions and structural/thermodynamic instability, which leads to capacity reduction and safety problems. Cubic brick (Ni0.8Co0.1Mn0.1)C2O4·2H2O particles with micron size are synthesized by co-precipitation method. The oxalic precursor is sintered with lithium hydroxide to obtain cubic mono-dispersion LiNi0.8Co0.1Mn0.1O2 micrometer particles. Structural stability, cycling performance, rate capability and compacting density of the cubic mono-dispersion material are investigated. Conventional spherical and irregular mono-dispersion LiNi0.8Co0.1Mn0.1O2 are also prepared for comparison. The results reveal that the cubic mono-dispersion LiNi0.8Co0.1Mn0.1O2 dramatically enhances the structural stability and cycling performance at a little cost of capacity and rate capability.

The large-scale and efficient synthesis of MnPO4·H2O is an urgent problem to be solved. In this paper, self-assembled dumbbell-shaped MnPO4·H2O particles were successfully synthesized just using KMnO4 and commercial concentrated H3PO4, and then employed as the precursor to prepare LiMnPO4/C composites. The XRD, SEM, TEM, and electrochemical performance tests were used to investigate MnPO4·H2O and the corresponding LiMnPO4/C. The formation mechanism of MnPO4·H2O was discussed. The results showed that temperature and water content have a significant effect on the yield, purity, and morphology of MnPO4·H2O. The synthesized LiMnPO4/C with reduced carbon content at 650 °C delivered a discharge capacity of 109.3 mA h g-1 at 1 C and 104.3 mA h g-1 at 2 C. This green and efficient synthesis method of MnPO4·H2O provides a new idea for the large-scale preparation of LiMnPO4/C cathode materials.

Clustered regularly interspaced short palindromic repeats, CRISPR, has recently emerged as a powerful molecular biosensing tool for nucleic acids and other biomarkers due to its unique properties such as collateral cleavage nature, room temperature reaction conditions, and high target-recognition specificity. Numerous platforms have been developed to leverage the CRISPR assay for ultrasensitive biosensing applications. However, to be considered as a new gold standard, several key challenges for CRISPR molecular biosensing must be addressed. In this paper, we briefly review the history of biosensors, followed by the current status of nucleic acid-based detection methods. We then discuss the current challenges pertaining to CRISPR-based nucleic acid detection, followed by the recent breakthroughs addressing these challenges. We focus upon future advancements required to enable rapid, simple, sensitive, specific, multiplexed, amplification-free, and shelf-stable CRISPR-based molecular biosensors.

Al-Cu binary alloys are important and interesting industry materials. Up to date, the formation mechanisms of the key strengthening precipitates, named θ′-phase, in the alloys are still controversial. Here, we report that for non-deformed bulk Al-Cu alloys the θ′-phase actually has its own direct precursors that can form only at elevated aging temperature (> ca. 200 °C). These high-temperature precursors have the same plate-like morphology as the θ′-phase precipitates but rather different structures. Atomic-resolution imaging reveals that they have a tetragonal structure with a = 0.405 nm and c = 1.213 nm, and an average composition of Al5-xCu1+x (0 ≤ x

Ni-rich LiNi0.8 Co0.15 Al0.05 O2 (NCA) material attracts extensive attention due to its high discharge specific capacity, but its distinct drawbacks of rapid capacity decline and poor cycle performance at elevated temperatures and high voltage during charge/discharge cycling restricts its widespread application. To solve these problems, a multifunctional coating layer composed of a lithium-ion-conductive lithium polyacrylate (LiPAA) inner layer and a cross-linked polymer outer layer from certain organic substances of silane-coupling agent (KH550) and polyacrylic acid (PAA) is successfully designed on the surface of NCA materials, which is favorable for eliminating residual lithium and improving lithium-ion conductivity, surface stability, and hydrophobicity of NCA materials. In addition, the amount of the coating material is also investigated. A series of characterization methods such as XRD, FTIR, SEM, TEM, and X-ray photoelectron spectroscopy are used to analyze the morphologies and structures for materials of pristine and modified NCA. It is revealed that the co-coating layer plays a vital part in reducing the surface residual alkalis and improving the stability of NCA particles; as a result, the modified NCA exhibits a greatly improved rate capability, cycle performance, and low polarization impedance.

LiMn0.8Fe0.2PO4 is a potential candidate cathode material to balance the energy density, safety, and cost of power lithium ion batteries. However, the low electronic conductivity and ion diffusion coefficient limit its application. Here, bimetallic oxalate Mn0.8Fe0.2C2O4·2H2O/graphene oxide (Mn0.8Fe0.2C2O4·2H2O/GO) is designed to synthesize homogeneously distributed LiMn0.8Fe0.2PO4/reduced graphene oxide/carbon (LiMn0.8Fe0.2PO4/rGO/C) composite. The influence of rGO on the morphologies, structure, and electrochemical performance of the as-synthesized composite is investigated. The composite LiMn0.8Fe0.2PO4/rGO/C delivers discharge capacity of 153.2 mAh g−1 at 0.05 C and 127.3 mAh g−1 at 5 C, and 97.2% capacity retention even after 300 cycles at 1 C. The results confirm that the introduction of rGO sheets can alleviate the agglomeration of LiMn0.8Fe0.2PO4 particles. Furthermore, the conductive network composed of rGO sheets and pyrolytic organic carbon links the particles together to improve the migration pathways of electrons and lithium ions, thus enhancing the electrochemical performance of LiMn0.8Fe0.2PO4/rGO/C.

The MMS-200 thermal simulation testing machine was used to study the static softening behavior of low carbon high niobium microalloyed steel. The effect of niobium to the static recrystallization softening behavior of the microalloy steel had been analyzed by establishing the kinetics model of static recrystallization and the micro-morphology of precipitates. The results indicated that: the static softening behavior of the tested steel significantly influenced by the deformation temperature and the interval pass time of the rolling processing. At relatively high deformation temperature and long interval pass time, the ratio of static softening was increased. Then the deformation temperature was lower to 950°C, and the static softening behavior of the test steel was ceased. But when the deformation temperature was higher than 1000°C, the static softening behavior of the test steel completely occurred. The activation energy of the test steel was 325·mol-1 by the established model calculated.

In this article, Li2MnO3 was successfully prepared by a facile one-step high-energy mechanical activation method free from sintering. XRD, SEM, and TEM techniques were employed to analyse the mater...

A novel micro- and nanofluidic device stacked with magnetic beads has been developed to efficiently trap, concentrate, and retrieve Escherichia coli (E. coli) from the bacterial suspension and pig plasma. The small voids between the magnetic beads are used to physically isolate the bacteria in the device. We used computational fluid dynamics, three-dimensional (3D) tomography technology, and machine learning to probe and explain the bead stacking in a small 3D space with various flow rates. A combination of beads with different sizes is utilized to achieve a high capture efficiency (∼86%) with a flow rate of 50 μL/min. Leveraging the high deformability of this device, an E. coli sample can be retrieved from the designated bacterial suspension by applying a higher flow rate followed by rapid magnetic separation. This unique function is also utilized to concentrate E. coli cells from the original bacterial suspension. An on-chip concentration factor of ∼11× is achieved by inputting 1300 μL of the E. coli sample and then concentrating it in 100 μL of buffer. Importantly, this multiplexed, miniaturized, inexpensive, and transparent device is easy to fabricate and operate, making it ideal for pathogen separation in both laboratory and point-of-care settings.

An electric hysteresis loop is derived according to dipole turning upon an applied electric field in 3D ferroelectrics by the Boltzmann statistic method via Gibbs free energy in the Devonshire’s theory. The loop shape varies with temperature, dipole coupling, and applied maximum electric field, which provides a corresponding theoretical method to derive temperature dependent energy storage density. By numerical simulation the result demonstrates that energy storage density peak appears and shifts towards high temperature with increasing electric field, which is in good agreement with experimental results. A mechanism revealed that the high energy storage density in paraelectric phase, a state of zero spontaneous polarization, is ascribed to a huge increase in polarization induced by electric field around the Curie’s temperature. Since ferroelectric dielectric constant is related to the induced polarization in principle, dielectric constant peak can be a direct indicator for the energy storage density peak.

Ni-rich layered LiNi0.8 Mn0.1 Co0.1 O2 (NCM811) cathode material has promising prospects for high capacity batteries at acceptable cost. However, LiNi0.8 Mn0.1 Co0.1 O2 cathode material suffers from surface structure instability and capacity degradation upon cycling. In this study, in situ ZrP2 O7 coating is introduced to provide a protective structure. The optimum modification amount is 1.0 wt %. A series of characterization methods (X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy) verify the generation and structure of the coating layer. Electrochemical performance tests demonstrate that the cycle retention rate increases from 66.35 to 86.92 % after 100 cycles at 1 C rate. The dense inorganic pyrophosphate layer not only has chemical stability against the electrolyte but also eliminates surface residual lithium. The protective layer and the matrix are strongly joined by high-temperature heating, thereby giving a certain mechanical strength and protecting the overall structure of the topography. Therefore, the cycle and rate performance are enhanced by the modification with ZrP2 O7 .

High-capacity LiNi0.90Co0.08Al0.02O2 with a Co-rich surface has been synthesized by a coprecipitation technique. The results of elemental, morphology, and structure analyses suggest that Co(OH)2 was uniformly coated on the nickel-cobalt-aluminum hydroxide precursor, providing a Co-rich surface layer on the Ni-based cathode material. Electrochemical tests and pH measurements demonstrated that the Co-rich coating increased the Li storage ability of the cathode. The cathode displayed high discharge capacity of ~ 207 mAh g−1 and 194 mAh g−1 at rates of 0.2°C and 1°C, respectively, and high-capacity retention of 90.2% after 100 cycles at rate of 1°C, representing better performance than that of the reference sample. The Co surface enrichment also decreased the pH of the material and restrained the formation of high-resistance Li-based residues during air exposure, illustrating that such a Co-rich surface can improve the storage stability of LiNi0.90Co0.08Al0.02O2.

The lithium-rich manganese cathode material Li2MnO3·LiMO2 (M = Mn, Co, Ni, Fe, etc.) has been received extensive attention for Li-ion batteries owing to its ultra-high specific capacity (>250 mAh g−1) and lower cost. Nevertheless, it is still strictly challengeable to achieve encouraging Li-storage behaviors due to its poor cyclability, rate performance, and voltage decay. Li-rich manganese cathode material Li1.2Mn0.54Ni0.13Co0.13O2 (LRNCM) modified by a novel hybrid conductive layer constructed with Li1.4Al0.4Ti1.6(PO4)3 (LATP) and polyaniline (PANI) is prepared. The hybrid modification layer (LATP&PANI) not only serves as a physical barrier to protect the active material from the electrolyte, but also combines the high ionic conductivity of Li1.4Al0.4Ti1.6(PO4)3 with the excellent electronic conductivity of polyaniline, helping for facilitating the transfer of electrons and lithium ions. The hybrid modification cathode material (LRNCM@3 wt%LATP@1 wt%PANI) displays favorable rate capability and cycle performance, whose capacity retention (2.0–4.8 V at 0.2 C, 25 °C) deliveries 79% after 200 cycles. The hybrid modification is a promising route for remarkable enhancement in performance of the lithium-rich manganese-based cathode materials.

The (1-x)LiFePO4·xLiVPO4F/C (x = 0, 0.05, 0.10, 0.20, 0.40, 0.60, 0.80, 1) composites with high rate performance were successfully prepared by an improved solid-phase method. Their physicochemical properties were characterized by different test instruments. Through X-ray Diffractometer and structural refinement, it was found that modification with certain amount of LiVPO4F on the LiFePO4 material induced bi-phase co-existence with mutual doping. By Scanning Electron Microscope and Transmission Electron Microscopy detection assisted with Energy Dispersion Spectrum and Fast Fourier Transform analysis, it can be confirmed that the composite material was evenly distributed. Sample 0.9LiFePO4·0.1LiVPO4F/C had the highest specific capacity and specific energy in all samples, with its discharge capacity of 137.4, 129.0, 121.4, 109.6 and 94.0 mAh g−1 at the rate of 3C, 5C, 7C, 10C and 15C, respectively. Furthermore, at the rate of 15C, the specific energy of 0.9LiFePO4·0.1LiVPO4F/C was more than 2 times of that of sample LiFePO4/C. After 800 cycles at 10C, the capacity retention ratio still maintained at 91.42%. Compared with the untreated material, sample 0.9LiFePO4·0.1LiVPO4F/C possessed smaller impedance and larger lithium diffusion coefficient, which is conducive to improve the electrochemical properties of LiFePO4 materials. It indicated that the heterogeneous double active phase shows good synergistic effect.

WO3 modified LiNi0.8Co0.1Mn0.1O2 materials were got by a wet method. Structure parameters, micromorphology, element distribution of the modified and bare NCM materials were compared by different detection methods, such as XRD, SEM, EDS and TEM. The results reveal that there was no significant change in morphology before and after modification, and the distribution of tungsten was relatively uniform. In addition, tungsten oxide surface modification layer does exist by TEM, FFT and XPS analysis, and affects the distribution and valence states of surface elements. Furthermore, it is found that the micro amount of tungsten oxide modified NCM material is beneficial to the improvement of rate performance and cycle stability, especially at high cutoff voltage. Then the effect of modification on the electrochemical properties was conducted by CV, EIS and SEM detection after cycle. It is displayed that the particles after modification have no cracks, and the polarization and impedance decrease to varying degrees. This simple and feasible method has a good prospect for improving the cyclic stability of Ni-rich materials.

LiMnPO4 cathode material has a high voltage platform and matches the existing electrolyte window, and thus researchers are constantly shifting their focus from LiFePO4 to LiMnPO4. However, LiMnPO4 has lower electron (ion) conductivity than LiFePO4, and besides, its delithiated phase MnPO4 will suffer thermal decomposition at lower temperatures more easily than FePO4. In order to effectively solve the above problems by elements substitution, DFT calculations are employed to screen for suitable dopants from a series of transition metals including Fe, Mg, Ni, V, Nb, Ti. Properties such as electronic structure, atomic Bader charge, O2 evolution Gibbs free energy, average voltages, and lithium ion diffusion energy barrier were evaluated. Based on the calculation, Fe is the most effective doping element because Fe doping is able to reduce the band gap of the material and improve the electronic conductivity, suppress the O2 evolution reaction of the delithiation phase and improve the thermal stability. The reason for such a situation is that Fe can form a stronger covalent bond with the surrounding O atoms to bind the escape of O. Fe doping reduces ion diffusion energy barrier to promote lithium ion diffusion. Electrochemical tests show that Fe doping can improve the electrochemical properties of LiMnPO4.

LiFePO4 cathode material is considered as prospective materials for lithium-ion batteries and attracted great interest because of excellent cyclic performance and environmentally friendliness. However, LiFePO4 material suffers from inferior electronic and Li+ conductivity, which restricts its performance at high rate. Improving the interfacial stability and the interfacial charge transfer of the electrode is a necessary method to enhance the cycle and rate capability. Herein, vanadium oxide decoration on LiFePO4/C composites was obtained via a simple wet chemical method. The results show that a moderate amount of vanadium oxide hybrid stabilizes the structure of the matrix LiFePO4 material. Vanadium oxide and the residual carbon coating construct a mixed conductive network, which optimizes the interface structure and reaction dynamics of the electrode. In addition, the charge transfer resistance of the decorated hybrid is smaller and the Li+ diffusion ability is better than pristine LiFePO4/C material. Moreover, the electrochemical performance exhibits a promising high rate capability and perfect cycle ability, showing the discharge specific capacities of 157.2, 150.6, and 131.1 mAh g−1 at 0.1 C, 1 C, and 3 C respectively. Furthermore, the capacity retention reached 90.9% after the 1000th cycle at 3 C.

The solid-state reaction has been widely employed as the standard procedure to prepare oxide cathode materials for sodium-ion batteries. However, it involves multiple steps and consumes much energy. In this work, we report a facile method to synthesize a large-grained O3–NaCrO2 cathode by directly reducing sodium dichromate dihydrate (Na2Cr2O7·2H2O) under a hydrogen atmosphere. Owing to its unique large particle morphology, the as-prepared NaCrO2 exhibits a high tap density of 2.55 g cm–3. The compact NaCrO2 shows excellent electrochemical performance with a high reversible capacity of 123 mAh g–1 at 0.1C, a high capacity retention of 88.2% after 500 cycles at 2C, and an outstanding rate capability of 68 mAh g–1 at 20C. The performance is attributed to a stable structure from the distinctive morphology with small specific surface area to suppress interfacial side reactions and rapid Na-ion diffusion channels with a highly (110)-oriented crystal structure. Ex situ X-ray diffraction and cyclic voltammetry t...

The Li-rich cathode material for long cycle performance and long-term storage performance is a challenge for next-generation lithium-ion batteries due to the rapid capacity degradation over cycling and the formation of residual lithium on the surface during long-term storage. Herein, an elevated performance of Li1.2Mn0.54Ni0.13Co0.13O2 materials via CeO2 inlay is reported, which was prepared from Li1.2Mn0.54Ni0.13Co0.13O2 by sol-gel inlay with CeO2. It was proved by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy that cerium oxide cladding not only covered the surface of the material but also diffused into the interior of the material change crystal structure. Cerium oxide on the cladding not only reduces the material's contact with water and carbon dioxide in the air, but also prevents the material from being corroded by electrolyte during electrochemical test. The position of the transition metal atom is replaced Ce atoms, which increases the unit cell volume and the stability of the Li-rich material during the cycling. The results show that the storage property and the electrochemical cycling property of the material have been improved obviously. The CeO2 inlaid lithium rich material discharged 204.6 mAh/g for the first time at the current of 1C, and 164.4 mAh/g after 150 charge and discharge cycles with corresponding capacity retention rate of 80.35%, compared with the retention rate of 57.26% for pristine Li-rich material capacity. After being stored in humid air for 40 days, the CeO2 inlaid lithium-rich material showed better electrochemical performance than the pristine one. It is powerfully demonstrated that the CeO2 inlay strategy here holds huge promise for surface modification of electrode materials for lithium-ion batteries.

Cracking carbon, grapheme as well as carbon nanotube co-modified LiVPO4F material (LiVPO4F/C/G/CNT) and cracking carbon modified LiVPO4F material (LiVPO4F/C) were respectively prepared by a two-step process. Physicochemical properties, electrochemical datas and kinetic parameters of LiVPO4F/C/G/CNT and LiVPO4F/C materials were obtained by various detection means. X-ray diffraction analysis (XRD) demonstrates that co-modification of multi-level carbon cannot change fundamental crystallographic structure of LiVPO4F/C/G/CNT material. Scanning electron microscopy (SEM) and High resolution transmission electron microscopy (HRTEM) synergistically reveal that cross-linked network structures formed by cracking carbon, grapheme and carbon nanotube are evenly distributed among the LiVPO4F particles, helping for charge transfer throughout the inside and outside of cathode materials. Compared with LiVPO4F/C material, the LiVPO4F/C/G/CNT material possesses many advantages such as higher discharge specific capacity, higher charge-discharge rate performance, smaller charge transfer impedance (Rct), and higher Li+ diffusion coefficient (DLi+), indicating that the LiVPO4F/C/G/CNT cathode material prepared by a two-step process shows better potential application prospect for lithium batteries.

The surface-fluorinated Li4Ti5O12 nanowires/reduced graphene oxide composite is synthesized through a hydrothermal procedure. Lithium ion transport is promoted by forming a special morphology of lithium titanate nanowires, meanwhile, electronic transmission is facilitated by surface fluorination and conductive network of graphene coating. These three kinds of synergistic effects greatly improve the rate performance of lithium titanate. The surface-fluorinated Li4Ti5O12 nanowires/reduced graphene oxide composite exhibits high specific capacities (167.5 mAh g−1 at 1 C and even 132.6 mAh g−1 at 10 C) and good cyclic stability (95% capacity remain after 300 cycles at 5 C). The influences of surface fluorination and graphene coating on electrochemical performance of lithium titanate are investigated in detail in terms of reversible capacity, cyclability and rate capability. Its excellent electrochemical properties make it become possible to be a potential anode material for high-rate lithium-ion batteries applied in high power facilities.

Highly infectious illness caused by pathogens is endemic especially in developing nations where there is limited laboratory infrastructure and trained personnel. Rapid point-of-care (POC) serological assays with minimal sample manipulation and low cost are desired in clinical practice. In this study, we report an automated POC system for Ebola RNA detection with RNA-guided RNA endonuclease Cas13a, utilizing its collateral RNA degradation after its activation. After automated microfluidic mixing and hybridization, nonspecific cleavage products of Cas13a are immediately measured by a custom integrated fluorometer which is small in size and convenient for in-field diagnosis. Within 5 min, a detection limit of 20 pfu/mL (5.45 × 107 copies/mL) of purified Ebola RNA is achieved. This isothermal and fully solution-based diagnostic method is rapid, amplification-free, simple, and sensitive, thus establishing a key technology toward a useful POC diagnostic platform.

Different content of Ti4+ has been successfully doped into the lattice sites of Cr3+ in NaCrO2 by the two step solid-state reaction. The analysis results of crystal structure demonstrate that the interslab (NaO2) spacing is increased with Ti doping content, which contributes to widening the sodium ion migration channel and then facilitating the rapid (de)intercalation capability of sodium ions. During charge-discharge processes, these O3-Na1-xCr1-xTixO2 (x = 0.03, 0.05, 0.1) layered oxides exhibit delayed O3-P3 phase transition and increased average discharge voltage due to stronger Ti-O bond relative to Cr-O bond. In particular, the Na0.95Cr0.95Ti0.05O2 shows the optimal electrochemical performance which releases a discharge specific capacity of 96.7 mAh g−1 at 1 C (100 mA g−1) with 80.1% capacity retention after 800 cycles. Even under the high rate of 30 C, it can deliver a discharge specific capacity of 67 mAh g−1.

LiMnPO4/C with hierarchical spindle structures was synthesized by a facile solvothermal method at 180 ℃ for 10 h. The morphology and structure of the prepared materials were controlled through the adjustment of hexamethylenetetramine (HMT). The synthesized materials were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Quantachrome instrument(Quabrasorb SI-3MP) and Fourier transform infrared spectroscopy (FTIR), and so on. The prepared LiMnPO4/C exhibits good electrochemical performance, for instance, there are 153.2, 126.3, 110.2 mA h g−1 at 0.05 C, 1 C, 2 C respectively. The promising properties of the materials results from unique hierarchical nanostructures and the uniform thin carbon coating of particle surface, which improve the ionic and electronic transfer of LiMnPO4.

The micro-nanosized LiFePO4/carbon particles have been successfully prepared via a novel mechanical milling process and subsequently carbothermal reduction reaction, using Fe powder, H3PO4, Li2CO3 and glucose as the reactants. Notably, the milling process is assisted by ultrasonic treatment. XRD, SEM, TEM and particle size detection are operated to investigate the structure, morphology and particle size distribution of the as-prepared products. The electrochemical performances are studied by CV, EIS and cyclic tests. The results show that the LiFePO4/carbon-ultrasonic-assisted particles are granular and uniformly distributed with high crystallinity, and the mean size of LiFePO4 powder is about 220 nm. The composite exhibits an excellent electrochemical performance and its initial discharge capacity reaches approximately 156.8, 149, 138, 128 and 119 mAh g−1 at rates of 0.2, 1, 2, 3 and 5 C, respectively. Meanwhile, it can keep the discharge capacity retention of 99.7% over 300 charge/discharge cycles at 1 C.

Herein, partially reduced graphite oxide (PRGO) was prepared by the thermal reduction of GO at 220 °C and investigated as a cathode material for lithium-ion batteries. After an initial galvanostatic charging process to 5.2 V, the PRGO shows a high capacity of 230 mA h g−1, and the capacity retention can reach approximately 90% even after 8000 cycles at 1 A g−1. XPS, Raman spectroscopy, FTIR spectroscopy and TEM analysis showed that the active oxygen functional groups obviously increased after electrochemical activation; this was considered the reason for the increase in capacity. In this study, we demonstrated a novel strategy for the preparation of high-performance organic cathode materials for lithium-ion batteries.

Lithium vanadium fluorophosphate (LiVPO4F) composite with three-dimensional conductive networks architecture is synthesized with synergistic modification of pyrolytic carbon (C), multi-walled carbon nanotubes (MWCNTs) and graphene sheets (rGO). The differences between LiVPO4F@C, LiVPO4F@C/MWCNTs, LiVPO4F@C/rGO and LiVPO4F@C/MWCNTs/rGO composites are compared through a variety of characterization means. By means of SEM and TEM analysis, it can be seen that pyrolyzed C, MWCNTs and rGO are interwoven, which forms a three-dimensional conductive network structure wrapping the LiVPO4F particles. The difference of discharge specific capacity between LiVPO4F@C and LiVPO4F@C/MWCNTs/rGO composites is becoming larger and larger with the increase of charge-discharge rate. Additionally, CV and EIS results indicate that the LiVPO4F@C/MWCNTs/rGO has the smallest polarization value and charge transfer impedance (Rct) as well as the highest diffusion coefficient of lithium ion (DLi+) in all samples. Consequently, LiVPO4F@C/MWCNTs/rGO composite exhibits a high rate capability (97.9 mAh/g cycles at 10 C) and cycling stability (93.74% capacity retention over 800 cycles at 10 C)，showing potential application for high power LIB with high voltage.

Fully biobased and high performance epoxy thermosets were synthesized through curing of epoxidized soybean oil (ESO) with crystalline diamino terminated polyamide 1010 oligomers (OPAs). Four OPAs with different molecular weights were prepared to cure ESO. The results of isothermal curing investigation indicated that the curing rate decreased with increasing molecular weight of the OPA. The effects of chain length of OPAs on the thermal transition, crystallization behavior mechanical properties, heat resistance and thermal stability of the ESO thermosets were investigated in detail. The results showed that the crystallization was significantly enhanced, the glass transition temperature and the melting temperature increased to a higher temperature range with increasing OPA chain length. The tensile strength, Young's modulus, storage modulus and elongation at break increased considerably with increasing OPA chain length, due to the gradually enhanced network stiffness through crystallization and reduced crosslink density through increasing chain length between crosslinking sites. The heat resistance of the thermosets was also enhanced with increasing OPA chain length due to the increased melting temperature of the thermoset. In addition, the biobased epoxy thermosets showed excellent thermal stability with onset decomposition temperature of higher than 330 °C.

The electrochemical properties of LiNi0.6Co0.2Mn0.2O2, such as cycling stability, rate capacity and coulomb efficiency, are not fairly well at large rate, high cutoff voltage and elevated temperature. In this article, a uniform nanoscale graphene@TiO2 coating layer is skillfully formed on the surface of LiNi0.6Co0.2Mn0.2O2 via an artful sol-gel-based method. The rGO@TiO2 layer is evidenced by a series of detections, and the structures of the pristine and coated materials are investigated in detail. It indicates that the graphene@TiO2 layer with a thickness of ∼2 nm is uniformly covered on the LiNi0.6Co0.2Mn0.2O2 particles. The “synergistic effects” of graphene@TiO2 composite plays an important role in improving the comprehensive electrochemical performances of the cathode material. Compared with the pristine material, the graphene@TiO2 co-modified LiNi0.6Co0.2Mn0.2O2 shows enhanced electrochemical performances at large rate, elevated temperature, and high cutoff voltage. Particularly, it displays capacity retentions of 93.7% and 89.2% after 150 cycles at 1 C and 2 C, respectively, over 3.0–4.5 V. Even at high temperature of 55 °C and upper operating voltage of 4.5 V, the capacity retention of graphene@TiO2-coated sample increases almost 50% compared with the pristine sample after 150 cycles.

We have developed a novel detection system that couples clustered regularly interspaced short palindromic repeat-Cas recognition of target sequences, Cas-mediated nucleic acid probe cleavage, and quantum dots as highly sensitive reporter molecules for simple detection of viral nucleic acid targets. After target recognition and Cas-mediated cleavage of biotinylated ssDNA probe molecules, the probe molecules are bound to magnetic beads. A complementary ssDNA oligonucleotide quantum dot conjugate is then added, which only hybridizes to uncleaved probes on the magnetic beads. After separating hybridized quantum dots, the collected supernatant is illuminated by a portable ultraviolet flashlight, and it provides a simple “Yes-or-No” nucleic acid detection answer. By using a DNA target matching part of the African swine fever virus, detection limits of ∼0.5 and ∼1.25 nM are achieved in buffer and porcine plasma, respectively. The positive samples are readily confirmed by visual inspection, completely avoiding the need for complicated devices and instruments. This work establishes the feasibility of a simple assay for nucleic acid screening in both hospitals and point-of-care settings.

A highly time-efficient approach based on liquid nitrogen quenching technique has been developed to synthesize over-lithiated oxide Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 . The improved morphology and crystal structure, as confirmed by X-ray diffraction (XRD) patterns, scanning and high-resolution transmission electron microscope (SEM and HRTEM), endow the material with impressive electrochemical performance. The as-prepared material shows a capacity of 265 mAh g −1 at 0.1 C. It almost exhibits no capacity fading and its working voltage is stabilized within a decaying variation of 0.05 V after 100 cycles at 0.1 C. The results indicate an immense potential of application of this technique for over-lithiated oxide as cathode material for lithium ion batteries.

Ni-rich cathode material attracts a substantial amount of attention due to its high specific capacity, superior energy density and low cost. Nonetheless, there are still a few intrinsic issues which need to be solved including rate performance, cycling stability, elevated-temperature performance, etc. In this paper, the graphene-analogous structural MoS2 with chemical stability and acceptable conductivity is purposefully introduced to modify LiNi0.8Co0.1Mn0.1O2 cathode material via a facile wet-chemical approach followed by low-temperature reaction. In addition, lithium-active MoS2 coating layer can provide an interconnected and stable tunnel for the insertion and extraction of lithium ions. Characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, Raman, scanning electron microscopy and transmission electron microscopy demonstrate that MoS2 coating layer is uniformly deposited on the surface of LiNi0.8Co0.1Mn0.1O2 material. The electrochemical results indicate that the modified cathode material displays excellent structure stability, superior rate performance and outstanding cycling properties.

A bio-based poly (urethane urea) (CIPUU) network comprised of castor oil (CO), isosorbide (IS) and 4-aminophenyl disulfide (APD) was prepared and compared to the corresponding polyurethane (CIPU) consisting of CO and IS. Permanently cross-linked CIPU could not be reprocessed, while CIPUU could be reprocessed, as the network topology could rearrange through an associative disulfide exchange reaction. CIPUU had a higher Young's modulus than CIPU due to the higher rigidity of APD with benzene rings and the formed hydrogen bonding of the urea unit. Stress relaxation measurement indicated that the network topology of CIPUU was stable at temperatures lower than 100 °C due to the inactive disulfide exchange reaction at low temperatures. The exchange reaction became increasingly active with increasing temperature, as evidenced by the gradually reduced relaxation time. CIPUU showed excellent reprocessability, as indicated by the remaining gel fraction and fully recovered mechanical properties after thermal remoulding at 180 °C several times. In addition, CIPUU showed good thermal stability with an onset decomposition temperature (∼260 °C) much higher than the reprocessing temperature.

The performance of LiNi0.8Co0.1Mn0.1O2 cathode materials has been significantly improved by Li4P2O7 surface modification. Some electrochemical tests are carried out to investigate the relevant performances of LiH2PO4-coated LiNi0.8Co0.1Mn0.1O2, such as inductively coupled plasma test (ICP), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results indicate that LiNi0.8Co0.1Mn0.1O2 is clad with a layer of average thickness about 30–40 nm. And the alkalinity on the surface of the modified materials has declined dramatically after titration measurement. The effect of surface modification can be credited to the two main factors: On the one hand, the weak acidity of LiH2PO4 neutralizes the lithium residues (LiOH/Li2CO3) on the surface of LiNi0.8Co0.1Mn0.1O2 cathode materials; on the other hand, LiH2PO4 continues to decompose and react with the unneutralized lithium residues to generate a coating layer of Li4P2O7 during the annealing process, which can prevent the active materials from contacting with the electrolyte directly and act as an outstanding Li+ conductor, thus inhibiting the interface reaction and improving the cycle performance as well as the rate properties of the host materials.

A series of layered Na0.67Lix(Ni0.2Fe0.15Mn0.65)1-xO2+δ (x = 0, 0.1, 0.2 and 0.3) compounds is prepared via a facile oxalate coprecipitation method and a solid-state reaction process, and investigated as the promising positive electrode materials for Na-ion batteries. As the Li content increases, O3 phase and Li2MnO3 gradually grow at the expense of the P2 phase and the particles become smaller and more agglomerated based on X-ray diffraction, scanning electron microscopy and transmission electron microscope results. The optimal Na0.67Li0.2(Ni0.2Fe0.15Mn0.65)0.8O2+δ shows the improved electrochemical performance with a high specific capacity of 151 mAh g−1 and 78% capacity retention over 50 cycles at 0.1 C (15 mA g−1). When tested at 5 C (750 mA g−1) rate, the electrode exhibits a discharge capacity of 68 mAh g−1. The results of electrochemical impedance spectroscopic and ex-situ X-ray diffraction measurements demonstrate that the improved cyclability and rate capability of the Li-substituted cathode can be ascribed to the decreased resistance and the enhanced structure stability in the high voltage of 4.3 V.

WO3-coated Li1.2Ni0.2Mn0.6O2 cathode materials have been synthesized by using co-precipitation method along with a liquid-evaporation coating process. Investigations via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) reveal that a WO3 layer is uniformly distributed on the surface of bulk Li1.2Ni0.2Mn0.6O2. After coating appropriate amount of WO3, the Li-rich cathode materials exhibit improved electrochemical performance. In particular, the 2 wt% WO3 coated sample (WO3-0.02 LLNMO) can deliver an initial discharge capacity of 252.2 mA h g-1 with a low irreversible capacity loss of 44.6 mA h g-1 and remarkable cycling stability of 97% capacity retention after 100 cycles at a current density of 52 mA g−1. This is mainly due to the effects of the WO3 coating layer which can suppress the initial activation of Li2MnO3 and improve the stability of surface structure of Li-rich materials by protecting it from corrosion by HF and other side reactions.

Super-hydrophobic materials for oil/water separation are usually prepared from non-renewable feedstocks, which does not coincide with the sense of sustainable development. Herein, we report a sustainable super-hydrophobic material fabricated via a simple spray-coating method from biobased feedstocks including epoxidized soybean oil, sebacic acid, stearic acid, zinc oxide and cotton fabric. Rough surface structure was successfully constructed by spraying epoxidized soybean oil (ESO) with sebacic acid (SA) and nano-ZnO. After modification with stearic acid (STA), the surface became super-hydrophobic with a water contact angle (WCA) of 155°. The super-hydrophobic fabric shows excellent stability without losing super-hydrophobicity after immersion in water and oil for several days. The super-hydrophobic fabric can selectively separate water mixtures with various oily liquids with separation efficiency higher than 97.5%. With high separation efficiency and excellent stability, the biobased super-hydrophobic fabric can be used as a sustainable and eco-friendly oil/water separation material.

Ni-rich ternary cathode materials have attracted great attention because of its high energy density, good cycle performance and high rate performance. However, it suffers from the poor electrochemical performance at elevated temperature and high cut-off voltage due to intrinsic grievous side effects. Herein, a core-shell structure of LiNi0.6Co0.2Mn0.2O2 as the core and Li1.2Ni0.2Mn0.6O2 as the shell which integrated the structural stability of Ni-rich materials and the surface chemical stability of Li-rich materials was purposefully designed via a polyvinyl pyrrolidone (PVP)-assisted sol-gel method and a novel chemical activation for the Li-rich shell with AlF3 treatment. Research by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy methods (TEM), and energy dispersive X-ray spectrometer (EDS) have been proved that the surface of the host materials was deposited with a uniform shell layer of Li1.2Ni0.2Mn0.6O2 and AlF3 particles. As a result, the core-shell materials displayed excellent cycle performance: 94.0% capacity retention after 100 cycles (2.0–4.5 V under 1C and 25 °C) especially at high temperature≈50 °C: 86.5% capacity retention.

Over-lithiated oxide has been attracting enormous attention due to its high work voltage and high specific capacity. However, the bottlenecks of low initial coulombic efficiency and voltage decay block its industrial application. In this paper, nano-sized Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 was successfully synthesized by a mechano-chemical activation-assisted microwave technique, in which Mn-Co-Ni-based micro spherical precursor by conventional co-precipitation method was ball milled with Li 2 CO 3 as lithium source and alcohol as dispersant into nano size and then sintered by microwave to obtain the final product. The as-prepared sample sintered for 30 min exhibited a superior electrochemical performance: almost no capacity fading after 100 cycles at 0.1 C. The rate performance was also improved significantly and the one sintered for 30 min delivered a discharge capacity of 239, 228, 215, 193 mA h g −1 at 0.1 C, 0.2 C, 0.5 C and 1 C respectively. The distinctive electrochemical performance benefits from the uniform nano-sized particle distribution and good electrode kinetics. It is concluded that such mechano-chemical activation-assisted microwave technique featuring high time and energy efficiency can be considered as one of the dominant routes to realize the industrialization of over-lithiated oxide.

The LiV1-xCoxPO4F/C (x = 0, 0.01, 0.03 and 0.05) composite cathode material for lithium ion batteries has been successfully prepared through the modified solid state method assisted by sonication and mechanical activation. Here, the influence of cobalt doping on the physical and electrochemical performances are investigated. In this paper, we adopted the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM)/energy dispersive spectrometer (EDS), cycle voltammetry (CV), electrochemical impedance spectrum (EIS) and charge-discharge test to investigate the influence of cobalt doping on the different aspects of the materials, including the physical and electrochemical properties. Compared with the original simple, the cycle and rate performance of cobalt doped samples has increased to some extent. We found that the LiV0.97Co0.03PO4F/C sample showed the best electrochemical performance. The lithium ions diffusion constant (DLi+) of the LiV0.97Co0.03PO4F/C (1.86321 × 10−13 cm2 s−1) is much higher than that of LiVPO4F/C (2.06453 × 10−14 cm2 s−1).

As a potential precursor for the scalable production of graphene, graphene oxide (GO) is of great importance, which can be prepared by the classical Hummers method. However, it is not only troublesome for separating and purifying GO from the obtained mixed liquor but also technically difficult to avoid the agglomeration of individual graphene sheets during the subsequent reduction process. In this paper, we introduce a novel design concept for fabricating 3D graphene (3D-rGO) directly from the GO mixed liquor with the assistant of sulphates. By using an artful anti-solvent precipitation method, sulphates (Na2SO4 and the impurities) are firstly generated on the surface of GO nanosheets, which are then removed by simple water-washing at the end of the synthesis. The choice of this method in the fabrication of rGO is motivated by the water-soluble nature of Na2SO4, which circumvents the intrinsic problems associated with the prevailing methods for GO separation, purification and reduction, making our approach green, highly efficient and cost-effective. The overall microstructure and phase evolutions of the samples at each step are observed and the formation mechanism of the rGO layers is also proposed. When evaluated as an anode material for Li-ion batteries, the obtained 3D-rGO exhibits the excellent electrochemical properties. The present approach inspires a new way for the fabrication of rGO powder on a large scale.

A well-crystallized (NH4)[Fe2(OH)(PO4)2]·2H2O particle with a red-blood-cell-like (RBC-like) shape has been synthesized via a simple sonochemical method, and is employed as the precursor to fabricate LiFePO4/C as a cathode material for Li-ion batteries. The morphology evolution of (NH4)[Fe2(OH)(PO4)2]·2H2O from a nanoparticle to a nanoplate (∼50 nm in thickness) and to a RBC-like discoid is observed by increasing the reaction time. The formation mechanism of this kind of RBC-like shape can be understood as nucleation, crystallization, formation of thin plates, and self-assembly. The precursor and corresponding LiFePO4/C are characterized by XRD, SEM, TEM, charge–discharge tests and CV measurements. The results show that the morphology of the (NH4)[Fe2(OH)(PO4)2]·2H2O precursor turns from a RBC-like structure into an irregular structure and the size becomes much smaller for LiFePO4/C during the solid-state reaction process. The fabricated LiFePO4/C exhibits excellent rate performance with a discharge capacity of 113.4 mA h g−1 even at 10C and a capacity fading rate of 3.5% after 300 cycles. Thus, this kind of uniquely shaped (NH4)[Fe2(OH)(PO4)2]·2H2O shows potential application in high-power Li-ion batteries.

In order to improve the electrochemical performance of LiMn2O4 at elevated temperatures, a series of Li1.2Ni0.2Mn0.6O2-modified LiMn2O4 samples have been synthesized by a facile sol-gel method. The structure and morphology of pristine and modified LiMn2O4 are investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The Li1.2Ni0.2Mn0.6O2 coating layer is identified by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), which plays an important role in reducing the dissolution of manganese, thereby improving the cycle performance and rate capability of the material. The 2 wt% Li1.2Ni0.2Mn0.6O2-modified LiMn2O4 sample exhibits a higher capacity retention of 95.88% than that of the pristine one (81.2%) after 200 cycles at 1C and 25 °C. Furthermore, a capacity retention of 89.74% is obtained for the 2 wt%-modified LiMn2O4 sample after 200 cycles at 1C and 55 °C, compared to 66.34% for the pristine one. Surface modification with a Li-rich Li1.2Ni0.2Mn0.6O2 material is a good way to improve the elevated temperature performance of LiMn2O4.

Herein, for the first time, the visible-light-driven 2D/1D Ti3C2/CdS nanorods composites were fabricated by electrostatic assembly strategy to achieve efficient uranium(VI) photoreduction without any sacrificial agents. While CdS is the main catalyst, Ti3C2 in the composites acts as a Janus co-catalyst for the photoreduction of uranium(VI), in view of the fact that it can simultaneously enhance the photocatalytic performance and the stability of CdS. With the initial uranium(VI) concentration at 50 ppm, 97% uranium(VI) reduction efficiency was achieved by the optimal Ti3C2/CdS composites during 40 min visible light irradiation without any sacrificial agents. The kinetic reaction rate reaches as high as 1520 μmol/(g·h). Meanwhile, the Ti3C2/CdS composites keep high performance regardless of acidic, neutral and alkali conditions. The findings of this work highlight the vast opportunities for Ti3C2/CdS composites in the treatment of radioactive wastewater.

Ni-rich cathode material is considered to be a promising cathode for commercial applications in lithium-ion batteries because of its low cost and high capacity. However, its chemical, electrochemical, and mechanical instability at the cathode-electrolyte interface cause a series of problems, such as inferior electrochemical performance and serious safety concerns. To construct a stable interface, we develop a simple and reproducible method to encapsulate LiNi0.8Co0.1Mn0.1O2 within ionic and electronic conductive half-cyclized polyacrylonitrile. The images of scanning electron microscopy and transmission electron microscopy prove that a continuous polymer layer formed on the surface of the cathode material. The organic coating layer is composed of both cyano groups that provide lithium-ion transport channels and cycled cyano groups that conduct electrons. At the same time, the elasticity of the coating polymer layer can maintain the mechanical stability of the cathode material during charge/discharge. Electrochemical studies demonstrate that the cycle and rate performances of LiNi0.8Co0.1Mn0.1O2 are obviously improved. After 100 cycles at a current density of 200 mA•g−1, the capacity retention is increased from 83.93 to 96.24%. The design of this real conformal coating strategy provides a possible solution for the modification of other cathode materials.

Ni0.6Co0.2Mn0.2(OH)2 with unique morphology of dispersed hexagonal slab particles is synthesized via the hydrothermal method, which reacts with lithium hydroxide to form single-crystalline LiNi0.6Co0.2Mn0.2O2 (SC-NCM) after a simple sintering process. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy testify the micrometer-sized SC-NCM particles display well-ordered layered structure with excellent crystallinity. Electrochemical characterization demonstrates that the LiNi0.6Co0.2Mn0.2O2 sample performs excellent capacity retentions of 93.2% (2.8–4.3 V) and 89.6% (2.8–4.5 V) after 100 cycles at a current rate of 1 C. In particular, LiNi0.6Co0.2Mn0.2O2 displays extraordinary rate property (174.5 mAh g−1 at 0.1 C and 130.7 mAh g−1 at 5 C). Therefore, it may provide a new method for the preparation of single-crystalline LiNixCoyMnzO2 materials with superior electrochemical performance.

A green strategy is designed for synthesizing LiMn0.8Fe0.2PO4/C composites bases on mechano-chemical liquid-phase activation technique. The micro-nano spherical precursor is prepared by the effective redox reaction between MnO2 and H2O2 in H3PO4 aqueous solution with subsequent addition FeC2O4•2H2O and Li2CO3, which is followed by spray drying. The dense LiMn0.8Fe0.2PO4/C microspheres are formed from conformal carbon coating connected with primary nano-sized particles, which provides rapid electron and ion transport pathways during the electrode reaction. The obtained LiMn0.8Fe0.2PO4/C cathode exhibits reduced electrochemical polarization with high voltage platform and high discharge capacity of 159 mAh g −1 at 0.1 C. Even at high rate of 10 C, the composite shows an impressing discharge capacity of 130 mAh g −1 with obviously stable plateau. Besides, uniformly conductive carbon network distributed all over the primary nano-sized particles effectively inhibits the occurrence of interfacial side reactions during electrode cycling, and the electrode exhibits good cycling stability with capacity retention rate of 95% after 500 cycles at 1 C. This work provides a scalable route to fabricate high energy density LiMn0.8Fe0.2PO4/C cathode with excellent rate performance for Li-ion battery.

A facile in-situ hydrolytic coating strategy has been suggested to architecture LiAlSiO4 (LASO)-coated LiNi0.8Co0.1Mn0.1O2 (LNCM) cathode material for lithium-ion batteries. Homogeneous LASO coating layer, as an one-dimensional lithium ion conductor, on the surface of LNCM is observed clearly and ascertained jointly by several testing methods. The effects of LASO coating layer on physicochemical properties, electrochemical properties and electrochemical kinetics of LNCM cathode material have been rigorously investigated by various tests. The cycling stability, rate capability and Li+ ion diffusion rate are enhanced evidently after LASO coating. Moreover, the polarization, impedance increase and particles cracking after cycles under the high cut-off voltage are greatly improved. These effective and obvious improvements are ascribed to the LASO coating layer, which could effectively inhibit the occurrence of side reactions and HF erosion and provide a fast ion diffusion channel for lithium ions on the surface of LNCM.

Graphene oxide (GO) is the key for the large-scale production of graphene by chemical oxidation-thermal reduction route. However, the current synthesis methods of GO involve concentrated sulfuric acid and potassium permanganate, which poses a risk of explosion and potential environmental pollution. Furthermore, a large number of oxygen-containing functional groups cause GO sheets to swell, posing a major challenge to the purification process. In this paper, a one-pot hydrothermal method is developed to synthesize pre-reduced graphene oxide (PRGO). The precursor is then employed to produce reduced graphene oxide (RGO) by further high-temperature thermal reduction. It not only avoids the complex temperature control and dilution operations during the oxidation and exfoliation processes but also enables the recycling of sulfuric acid. The synthesized weakly hydrophilic PRGO is highly conducive to achieve rapid filtration, which simplifies the purification process. The obtained reduced graphene oxide exhibits high rate capability and stable long cycling performance as the anode of lithium-ion batteries. This simple, safe and green synthesis route paves the way to large-scale preparation of graphene and its application for Li-ion storage.