Doping Effects on Ternary Cathode Materials for Lithium-ion Batteries：A Review.

The ongoing advancements in lithium-ion battery technology are pivotal in propelling the performance of modern electronic devices and electric vehicles. Amongst various components, the cathode material significantly influences the battery performance, such as the specific capacity, capacity retention and the rate performance. Ternary cathode materials, composed of nickel, manganese, and cobalt (NCM), offer a balanced combination of these traits. Recent developments focus on elemental doping, which involves substituting a fraction of NCM constituent ions with alternative cations such as aluminum, titanium, or magnesium. This strategic substitution aims to enhance structural stability, increase capacity retention, and improve resistance to thermal runaway. Doped ternary materials have shown promising results, with improvements in cycle life and operational safety. However, the quest for optimal doping elements and concentrations persists to maximize performance while minimizing cost and environmental impact, ensuring the progression towards high-energy-density, durable, and safe battery technologies.

Atomic Horizons Interpretation on Enhancing Electrochemical Performance of Ni-Rich NCM Cathode via W Doping: Dual Improvements in Electronic and Ionic Conductivities from DFT Calculations and Experimental Confirmation.

The rapid capacity degradation and poor rate capability hinder the application of Rich-Ni layered LiNix Coy Mnz O2 (NCM) as cathode materials for high-energy lithium-ion batteries. In this study, density functional theory (DFT) calculations, combined with conventional electrochemical measurements, reveal from the atomic view that the dual improvements in electronic and ionic conductivities are the main facts for the property enhancement. The bandgap of the cathode material is reduced to 1.1623 eV due to the increased number of electrons near the Fermi level after W intercalation. Such improved electronic conductivity subsequently leads to a suppressed polarization and reduced resistance, enabling an improved cycle life of up to 93.97% after 100 cycles at 0.5 C. Furthermore, the doping with W6+ also introduced a strong WO bond into the layered structure so that the thickness of the Li slab is expanded to 2.6476 Å, which reduces the energy barrier from 0.355 to 0.308 eV for the migration of Li+ within the Li slab, as confirmed by the DFT calculation. Consequently, the rate performance is greatly improved due to the reduced diffusion energy, with a specific capacity of 159.11 mAg-1 even at 5 C rate, indicating high potential for future applications.

Enhanced Electrochemical Performance of Li1.27Cr0.2Mn0.53O2 Layered Cathode Materials via a Nanomilling-Assisted Solid-state Process.

Li1.27Cr0.2Mn0.53O2 layered cathodic materials were prepared by a nanomilling-assisted solid-state process. Whole-pattern refinement of X-ray diffraction (XRD) data revealed that the samples are solid solutions with layered α-NaFeO2 structure. SEM observation of the prepared powder displayed a mesoporous nature composed of tiny primary particles in nanoscale. X-ray photoelectron spectroscopy (XPS) studies on the cycled electrodes confirmed that triple-electron-process of the Cr3+/Cr6+ redox pair, not the two-electron-process of Mn redox pair, dominants the electrochemical process within the cathode material. Capacity test for the sample revealed an initial discharge capacity of 195.2 mAh·g-1 at 0.1 C, with capacity retention of 95.1% after 100 cycles. EIS investigation suggested that the high Li ion diffusion coefficient (3.89 × 10-10·cm²·s-1), caused by the mesoporous nature of the cathode powder, could be regarded as the important factor for the excellent performance of the Li1.27Cr0.2Mn0.53O2 layered material. The results demonstrated that the cathode material prepared by our approach is a good candidate for lithium-ion batteries.

Photoluminescence and afterglow behavior of Ce3+ activated Li2Sr0.9Mg0.1SiO4 phosphor.

A blue emitting phosphor Li2Sr0.9Mg0.1SiO4:Ce3+, with long persistence, was synthesized via a high-temperature solid phase method. According to the X-ray diffraction analysis result, the introduction of Mg2+ and Ce3+ ions has no influence on the structure of the host material. Typical 5d-2F5/2 and 5d-2F7/2 transitions of Ce3+ ions were detected by PL spectra, which corresponded to the CIE chromaticity coordinates of x = 0.1584, y = 0.0338. An optimal doping concentration of Ce3+ was determined as of 0.4 at%. Furthermore, the Li2Sr0.9Mg0.1SiO4:Ce3+ phosphor showed a typical triple-exponential afterglow behavior when the UV source was switched off. The highest lifetime of the electrons within the material reached a value of 73.9 s. Thermal stimulated luminescence study indicated that the afterglow of Li2Sr0.9Mg0.1SiO4:Ce3+ was due to the recombination of the electrons with holes released from the traps generated by the doping of Ce3+ ions in the Li2Sr0.9Mg0.1SiO4 host. The afterglow mechanism of Li2Sr0.9Mg0.1SiO4:Ce3+ is illustrated and discussed in detail on the basis of the experimental results.

A Single Bout of Exercise Reduces Postprandial Lipemia but Has No Delayed Effect on Hemorheological Variables.

High plasma triglyceride (TG) concentration in fasting state could cause hemorheological abnormality, thus increasing the incidence of metabolic diseases. Exercise has been reported to effectively reduce postprandial TG response. This study aimed to investigate whether a single bout of pre-prandial exercise can affect lipemia and hemorheological variables after a high-fat meal. Nine healthy young male subjects completed two experimental trials. The subjects walked for 1 h at 50% maximal oxygen uptake (V̇O2max) (the exercise, EX trial), or rested (the control, CON trial). In the next morning, the subjects consumed a high-fat meal, and the postprandial lipemia and hemorheological responses were monitored for 6 h. The results showed that postprandial plasma TG concentrations were significantly lower in the EX trial compared to the CON trial. The postprandial low-density lipoproteins (LDL) concentration declined in the first 2 h and then gradually returned to the baseline level in both trials. The postprandial blood viscosity also decreased in the CON trial. There was no significant difference in postprandial blood viscosity, red blood cell (RBC) deformation index and aggregation degree between the trials. There was no significant correlation between plasma TG concentration and blood viscosity. In conclusion, brisk walking effectively reduced postprandial TG concentration, but has no significant impact on postprandial blood viscosity, RBC deformation index and RBC aggregation index.

Efficient Active Oxygen Free Radical Generated in Tumor Cell by Loading-(HCONH2)·H2O2 Delivery Nanosystem with Soft-X-ray Radiotherapy.

Tumor hypoxia is known to result in radiotherapy resistance and traditional radiotherapy using super-hard X-ray irradiation can cause considerable damage to normal tissue. Therefore, formamide peroxide (FPO) with high reactive oxygen content was employed to enhance the oxygen concentration in tumor cells and increase the radio-sensitivity of low-energy soft-X-ray. To improve stability of FPO, FPO is encapsulated into polyacrylic acid (PAA)-coated hollow mesoporous silica nanoparticles (FPO@HMSNs-PAA). On account of the pH-responsiveness of PAA, FPO@HMSNs-PAA will release more FPO in simulated acidic tumor microenvironment (pH 6.50) and subcellular endosomes (pH 5.0) than in simulated normal tissue media (pH 7.40). When exposed to soft-X-ray irradiation, the released FPO decomposes into oxygen and the generated oxygen further formed many reactive oxygen species (ROS), leading to significant tumor cell death. The ROS-mediated cytotoxicity of FPO@HMSNs-PAA was confirmed by ROS-induced green fluorescence in tumor cells. The presented FPO delivery system with soft-X-ray irradiation paves a way for developing the next opportunities of radiotherapy toward efficient tumor prognosis.

The Influence of Pre-Exercise Glucose versus Fructose Ingestion on Subsequent Postprandial Lipemia.

Ingestion of low glycemic index (LGI) carbohydrate (CHO) before exercise induced less insulin response and higher fat oxidation than that of high GI (HGI) CHO during subsequent exercise. However, the effect on the subsequent postprandial lipid profile is still unclear. Therefore, the aim of this study was to investigate ingestion of CHO drinks with different GI using fructose and glucose before endurance exercise on the subsequent postprandial lipid profile. Eight healthy active males completed two experimental trials in randomized double-blind cross-over design. All participants ingested 500 mL CHO (75 g) solution either fructose (F) or glucose (G) before running on the treadmill at 60% VO2max for 1 h. Participants were asked to take an oral fat tolerance test (OFTT) immediately after the exercise. Blood samples were obtained for plasma and serum analysis. The F trial was significantly lower than the G trial in TG total area under the curve (AUC; 9.97 ± 3.64 vs. 10.91 ± 3.56 mmol × 6 h/L; p = 0.033) and incremental AUC (6.57 ± 2.46 vs. 7.14 ± 2.64 mmol/L × 6 h, p = 0.004). The current data suggested that a pre-exercise fructose drink showed a lower postprandial lipemia than a glucose drink after the subsequent high-fat meal.

LiNi0.8Co0.15Al0.05O2: Enhanced Electrochemical Performance From Reduced Cationic Disordering in Li Slab.

Sub-micron sized LiNi0.8Co0.15Al0.05O2 cathode materials with improved electrochemical performance caused by the reduced cationic disordering in Li slab were synthesized through a solid state reaction routine. In a typical process, spherical precursor powder was prepared by spray drying of a uniform suspension obtained from the ball-milling of the mixture of the starting raw materials. Then the precursor powders were pressed into tablets under different pressures and crushed into powder. The pressing treated powders were finally calcinated under oxygen atmosphere to obtain the target cathode materials. XRD investigation revealed a hexagonal layered structure without impurity phase for all samples and significant increase in the diffraction intensity ratio of I(003)/I(104) was observed. Rietveld refinement further confirmed the reduced cationic disordering in Li slab by such pressing treatment, and the smallest disordering was observed for sample S4 with only 1.3% Ni ions on Li lattice position. The electrochemical testing showed an improvement in electrochemical behavior for those pressing treated samples. The calculation of diffusion coefficients using EIS data showed improved Li diffusion coefficient after pressing treatment. The sample S4 presented a diffusion coefficient of 4.36 × 10-11 cm2·s-1, which is almost 3.5 times the value of untreated sample.

Energy replacement using glucose does not increase postprandial lipemia after moderate intensity exercise.

BACKGROUND: Aerobic exercise can decrease postprandial triglyceride (TG) concentrations but the relationship between exercise-induced energy deficits and postprandial lipemia is still unclear. The aim of the present study was to examine the effect of a single bout of aerobic exercise, with and without energy replacement, on postprandial lipemia and on peripheral blood mononuclear cell (PBMC) mRNA expression of very low density lipoprotein (VLDL) and low density lipoprotein (LDL) receptors and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). METHODS: Nine healthy male humans completed three two-day trials in a random order. On day 1, volunteers rested (CON), completed 60 minutes of treadmill walking at 50% of VO2peak (EX) or completed the same bout of walking but with the energy replaced afterwards with a glucose solution (EXG). On day 2, volunteers rested and consumed a high fat test meal in the morning. RESULTS: Total and incremental TG AUC were significantly lower on the EXG (P < 0.05) and EX (P < 0.05) trials than the CON trial with no difference between the two exercise trials. No significant difference was observed in VLDL or LDL receptor mRNA expression among the trials (P > 0.05). CONCLUSIONS: In conclusion, energy replacement by glucose did not affect the decrease in postprandial TG concentrations observed after moderate intensity exercise and exercise does not affect changes in PBMC HMGCR, VLDL and LDL receptor mRNA expression.

The preparation of LiCoO2 nanoplates via a hydrothermal process and the investigation of their electrochemical behavior at high rates.

We report an alternative hydrothermal process for the preparation of pure phase LiCoO(2) cathode material for potential application under high rates. By adjusting the hydrothermal conditions, nanoplate-like LiCoO(2) crystals were obtained, with grain size about 200 nm. It was found in the experiment that the H(2)O(2) concentration and hydrothermal temperature were the two key factors that influence the phase purity and crystal shape, while LiOH concentration has only a slight effect on the crystal size of the product. The electrochemical test revealed a good rate behavior of the synthesized pure phase LiCoO(2) nanoplates, demonstrating a potential of the hydrothermal process for mass production.

The pseudo-single-crystal method: a third approach to crystal structure determination.

A novel method that enables single-crystal diffraction data to be obtained from a powder sample is presented. A suspension of LiCoPO(4) microrods was subjected to a frequency-modulated dynamic elliptical magnetic field to align the microrods; the alignment achieved was consolidated by photopolymerization of the suspending UV-curable monomer. The composite thus obtained (referred to as a pseudo single crystal) gave rise to X-ray diffraction data from which the crystal structure was solved using the standard method for single-crystal X-ray analyses. The structure determined was in good agreement with that reported using a conventional single crystal.

[Histomorphometric osseointegration evaluation of hydroxyapatite-coated and non-coated implants in dogs].

OBJECTIVE: Some reports showed the benefits of dental implants coated with hydroxyapatite, while some other studies found no significant difference between HA-coated implants and non-coated implants. The present study was to examine the osseointegration of HA-coated and non-coated implants in dogs. METHODS: Twelve implants, 6 HA-coated and 6 non-coated were placed into mandibles of six dogs after teeth extraction. Animals were sacrificed after 1, 3, 6 months, respectively. Initial healing and the bone-implant interface were histomorphometrically assessed using light microscopy. RESULTS: All implants osseointegrated; however, the ingrowth and development of new bone tissue onto HA-coated implants surface were sooner than that of non-coated ones. The index of bone osseointegration of HA-coated implants was higher than that of non-coated ones. After 1,3,6 months the osseointegration of HA-coated implants were 71.68%, 86.81%, 90.19%; While the non-coated ones'were 53.26%, 66.16%, 68.72%. The differences of them were very significant. CONCLUSION: HA-coated implants enhanced initial bone tissue ingrowth and development and thus benefited the osseointegration of implants.