Scalable Precursor-Assisted Synthesis of a High Voltage LiNiyCo1-yPO4 Cathode for Li-Ion Batteries.

A solid-solution cathode of LiCoPO4-LiNiPO4 was investigated as a potential candidate for use with the Li4Ti5O12 (LTO) anode in Li-ion batteries. A pre-synthesized nickel-cobalt hydroxide precursor is mixed with lithium and phosphate sources by wet ball milling, which results in the final product, LiNiyCo1-yPO4 (LNCP) by subsequent heat treatment. Crystal structure and morphology of the product were analyzed by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Its XRD patterns show that LNCP is primarily a single-phase compound and has olivine-type XRD patterns similar to its parent compounds, LiCoPO4 and LiNiPO4. Synchrotron X-ray absorption spectroscopy (XAS) analysis, however, indicates that Ni doping in LiCoPO4 is unfavorable because Ni2+ is not actively involved in the electrochemical reaction. Consequently, it reduces the charge storage capability of the LNCP cathode. Additionally, ex situ XRD analysis of cycled electrodes confirms the formation of the electrochemically inactive rock salt-type NiO phase. The discharge capacity of the LNCP cathode is entirely associated with the Co3+/Co2+ redox couple. The electrochemical evaluation demonstrated that the LNCP cathode paired with the LTO anode produced a 3.12 V battery with an energy density of 184 Wh kg-1 based on the cathode mass.

The Preparation and Characterization of N,N-Dimethyl Acrylamide-Diallyl Maleate Gel/Hydrogel in a Non-Aqueous Solution.

A few drugs need non-aqueous gels for release in the specific region of the intestine. The present work focuses on preparing N,N-Dimethyl acrylamide-Diallyl Maleate (DMAA-DAM) gel in Dimethyl sulfoxide (DMSO) solvent by applying different doses of gamma radiation and then characterization. The blend solution of 10%: 10%-DMAA: DAM was prepared in DMSO and irradiated at 2, 5, 10, 20, and 30 kGy doses from the Co-60 gamma source. After extraction, it was observed that all of the radiation doses yielded more than 95% gel content. The best gel content was found for 10 kGy dose, which was 97%. The equilibrium swelling was optimized 1800% of the dried gel for 5 kGy dose. Gel formation was confirmed by analyzing characteristic functional groups and the environment of protons in the gel structure by using FTIR and NMR spectroscopy. The thermal stability was tested using DSC and TGA which showed the glass transition temperature at 86.55 °C and the degradation started at 320 °C. The XRD pattern analysis revealed the semi-crystalline nature of the gel. Therefore, DMAA-DAM gels can be a good candidate for use in different fields of study, especially in drug delivery.

Recent Update and Drug Target in Molecular and Pharmacological Insights into Autophagy Modulation in Cancer Treatment and Future Progress.

Recent evidence suggests that autophagy is a governed catabolic framework enabling the recycling of nutrients from injured organelles and other cellular constituents via a lysosomal breakdown. This mechanism has been associated with the development of various pathologic conditions, including cancer and neurological disorders; however, recently updated studies have indicated that autophagy plays a dual role in cancer, acting as a cytoprotective or cytotoxic mechanism. Numerous preclinical and clinical investigations have shown that inhibiting autophagy enhances an anticancer medicine's effectiveness in various malignancies. Autophagy antagonists, including chloroquine and hydroxychloroquine, have previously been authorized in clinical trials, encouraging the development of medication-combination therapies targeting the autophagic processes for cancer. In this review, we provide an update on the recent research examining the anticancer efficacy of combining drugs that activate cytoprotective autophagy with autophagy inhibitors. Additionally, we highlight the difficulties and progress toward using cytoprotective autophagy targeting as a cancer treatment strategy. Importantly, we must enable the use of suitable autophagy inhibitors and coadministration delivery systems in conjunction with anticancer agents. Therefore, this review briefly summarizes the general molecular process behind autophagy and its bifunctional role that is important in cancer suppression and in encouraging tumor growth and resistance to chemotherapy and metastasis regulation. We then emphasize how autophagy and cancer cells interacting with one another is a promising therapeutic target in cancer treatment.

Electrochemical Storage Behavior of a High-Capacity Mg-Doped P2-Type Na2/3Fe1-yMnyO2 Cathode Material Synthesized by a Sol-Gel Method.

Grid-scale energy storage applications can benefit from rechargeable sodium-ion batteries. As a potential material for making non-cobalt, nickel-free, cost-effective cathodes, earth-abundant Na2/3Fe1/2Mn1/2O2 is of particular interest. However, Mn3+ ions are particularly susceptible to the Jahn-Teller effect, which can lead to an unstable structure and continuous capacity degradation. Modifying the crystal structure by aliovalent doping is considered an effective strategy to alleviate the Jahn-Teller effect. Using a sol-gel synthesis route followed by heat treatment, we succeeded in preparing an Mg-doped Na2/3Fe1-yMnyO2 cathode. Its electrochemical properties and charge compensation mechanism were then studied using synchrotron-based X-ray absorption spectroscopy and in situ X-ray diffraction techniques. The results revealed that Mg doping reduced the number of Mn3+ Jahn-Teller centers and alleviated high voltage phase transition. However, Mg doping was unable to suppress the P2-P'2 phase transition at a low voltage discharge. An initial discharge capacity of about 196 mAh g-1 was obtained at a current density of 20 mAh g-1, and 60% of rate capability was maintained at a current density of 200 mAh g-1 in a voltage range of 1.5-4.3 V. This study will greatly contribute to the ongoing search for advanced and efficient cathodes from earth-abundant elements for rechargeable sodium-ion batteries operable at room temperature.

MoO3@MoS2 Core-Shell Structured Hybrid Anode Materials for Lithium-Ion Batteries.

We explore a phase engineering strategy to improve the electrochemical performance of transition metal sulfides (TMSs) in anode materials for lithium-ion batteries (LIBs). A one-pot hydrothermal approach has been employed to synthesize MoS2 nanostructures. MoS2 and MoO3 phases can be readily controlled by straightforward calcination in the (200-300) °C temperature range. An optimized temperature of 250 °C yields a phase-engineered MoO3@MoS2 hybrid, while 200 and 300 °C produce single MoS2 and MoO3 phases. When tested in LIBs anode, the optimized MoO3@MoS2 hybrid outperforms the pristine MoS2 and MoO3 counterparts. With above 99% Coulombic efficiency (CE), the hybrid anode retains its capacity of 564 mAh g-1 after 100 cycles, and maintains a capacity of 278 mAh g-1 at 700 mA g-1 current density. These favorable characteristics are attributed to the formation of MoO3 passivation surface layer on MoS2 and reactive interfaces between the two phases, which facilitate the Li-ion insertion/extraction, successively improving MoO3@MoS2 anode performance.

Unveiling the mechanism of sodium ion storage for needle-shaped ZnxCo3-xO4 nanosticks as anode materials.

The interest in the development of micro-nanostructured metal oxides has been increasing recently because of their advantages as electrode materials in energy storage applications. In this study, dandelion-like ZnxCo3-xO4 microspheres assembled with porous needle-shaped nanosticks were synthesized by co-precipitation followed by a post-annealing treatment. The open space between neighboring nanosticks enables easy infiltration of the electrolyte; therefore, each nanostick is surrounded by the electrolyte solution, which ensures proper utilization of the active material during the electrochemical reaction. The dandelion-like ZnxCo3-xO4 hierarchical microspheres exhibit a greatly improved electrochemical performance with a high capacity and good cyclability as anodes for sodium-ion batteries (SIBs). A high initial reversible capacity of 612 mA h g-1 (at 35 mA g-1, ∼0.04C) is obtained and a capacity of 349 mA h g-1 is retained after 200 cycles. Meanwhile, the electrode shows a high rate performance with a capacity of 246 mA h g-1 at 2.0C-rate. The conversion of ZnxCo3-xO4 with Na is followed by ex situ X-ray absorption spectroscopy (XAS) and transmission electron microscopy (TEM) in different sodiation/de-sodiation states during electrochemical cycling. These analyses reveal that Na insertion/extraction is followed by complete reduction/oxidation of both metallic cobalt and zinc. The development of metallic Co and Zn after complete discharge and the formation of Co3O4 and ZnO when the electrode was fully recharged were identified by ex situ TEM analysis. In addition, the ZnxCo3-xO4 anode demonstrates feasible operation in a full cell by pairing with a NaNi2/3Bi1/3O2 cathode, affording a sodium-ion battery with an average working voltage of 2.6 V.

Kinetic and Electrochemical Reaction Mechanism Investigations of Rodlike CoMoO4 Anode Material for Sodium-Ion Batteries.

Sodium-ion batteries are considered the most promising power source for electrical energy storage systems because of the abundance of sodium and their significant cost advantages. However, high-performance electrode materials are required for their successful application. Herein, we report a monoclinic-type CoMoO4 material which is synthesized by a simple solution method. An optimized calcination temperature with a high crystallinity and a rodlike morphology of the material are selected after analyzing the as-synthesized powder by temperature-dependent time-resolved X-ray diffraction. The CoMoO4 rods exhibit initial discharge and charge capacities of 537 and 410 mA h g-1, respectively, when used as an anode for sodium-ion batteries. The sodium diffusion coefficient in the bimetallic CoMoO4 anode is measured using the galvanostatic intermittent titration technique and calculated in the range of 1.565 × 10-15 to 4.447 × 10-18 cm2 s-1 during the initial cycle. Further, the reaction mechanism is investigated using ex situ X-ray diffraction and X-ray absorption spectroscopy, and the obtained results suggest an amorphous-like structure and reduction/oxidation of Co and Mo during the sodium insertion/extraction process. Ex situ transmission electron microscopy and energy-dispersive spectroscopy images of the CoMoO4 anode in fully discharged and recharged state reveal the rodlike morphology with homogenous element distribution.

Probing the Sodium Insertion/Extraction Mechanism in a Layered NaVO3 Anode Material.

For the realization of sodium-ion batteries (SIBs), high-performance anode materials are urgently required with the advantages of being low-cost and environment-friendly. In this work, layered-type NaVO3 is prepared by the simple solid-state route with a rod-like morphology and used as an anode material for SIBs. The NaVO3 electrode exhibits a high specific capacity of 196 mA h g-1 during the first cycle and retains a capacity of 125 mA h g-1 at the 80th cycle with a high Coulombic efficiency of >99%, demonstrating high reversibility. The sodium diffusion coefficient in NaVO3 is measured using electrochemical impedance spectroscopy (1.368 × 10-15 cm2 s-1), the galvanostatic intermittent titration technique (1.15715 × 10-13 cm2 s-1), and cyclic voltammetry (2.7935 × 10-16 cm2 s-1). Furthermore, the reaction mechanism during the sodiation/desodiation process is investigated using in situ X-ray diffraction and X-ray absorption near the edge structure analysis, which suggests the formation of an amorphous-like phase and reversible redox reaction of V4+ ↔ V5+, respectively.

A 4†V Li-Ion Battery using All-Spinel-Based Electrodes.

Boosting the performance of rechargeable lithium-ion batteries (LIBs) beyond the state-of-the-art is mandatory toward meeting the future energy requirements of the consumer mass market. The replacement of conventional graphite anodes with conversion-type metal-oxide anodes is one progressive approach toward achieving this goal. Here, a LIB consisting of a highcapacity spinel NiMn2 O4 anode and a high-voltage spinel LiNi0.5 Mn1.5 O4 cathode was proposed. Polyhedral-shaped NiMn2 O4 powder was prepared from a citrate precursor via the sol-gel method. Electrochemical tests showed that the NiMn2 O4 in a half-cell configuration could deliver reversible capacities of 750 and 303 mAh g-1 at 0.1 and 3 C rates. Integrating the NiMn2 O4 anode into a full-cell configuration provided an estimated energy density of 506 Wh kg-1 (vs. cathode mass) upon 100 cycles and excellent cycling performance over 150 cycles at the 0.1 C rate, which can be considered promising in terms of satisfying the demands for high energy densities in large-scale applications.

Self-Rearrangement of Silicon Nanoparticles Embedded in Micro-Carbon Sphere Framework for High-Energy and Long-Life Lithium-Ion Batteries.

Despite its highest theoretical capacity, the practical applications of the silicon anode are still limited by severe capacity fading, which is due to pulverization of the Si particles through volume change during charge and discharge. In this study, silicon nanoparticles are embedded in micron-sized porous carbon spheres (Si-MCS) via a facile hydrothermal process in order to provide a stiff carbon framework that functions as a cage to hold the pulverized silicon pieces. The carbon framework subsequently allows these silicon pieces to rearrange themselves in restricted domains within the sphere. Unlike current carbon coating methods, the Si-MCS electrode is immune to delamination. Hence, it demonstrates unprecedented excellent cyclability (capacity retention: 93.5% after 500 cycles at 0.8 A g-1), high rate capability (with a specific capacity of 880 mAh g-1 at the high discharge current density of 40 A g-1), and high volumetric capacity (814.8 mAh cm-3) on account of increased tap density. The lithium-ion battery using the new Si-MCS anode and commercial LiNi0.6Co0.2Mn0.2O2 cathode shows a high specific energy density above 300 Wh kg-1, which is considerably higher than that of commercial graphite anodes.

Study on the Electrochemical Reaction Mechanism of NiFe2O4 as a High-Performance Anode for Li-Ion Batteries.

Nickel ferrite (NiFe2O4) has been previously shown to have a promising electrochemical performance for lithium-ion batteries (LIBs) as an anode material. However, associated electrochemical processes, along with structural changes, during conversion reactions are hardly studied. Nanocrystalline NiFe2O4 was synthesized with the aid of a simple citric acid assisted sol-gel method and tested as a negative electrode for LIBs. After 100 cycles at a constant current density of 0.5 A g-1 (about a 0.5 C-rate), the synthesized NiFe2O4 electrode provided a stable reversible capacity of 786 mAh g-1 with a capacity retention greater than 85%. The NiFe2O4 electrode achieved a specific capacity of 365 mAh g-1 when cycled at a current density of 10 A g-1 (about a 10 C-rate). At such a high current density, this is an outstanding capacity for NiFe2O4 nanoparticles as an anode. Ex-situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) were employed at different potential states during the cell operation to elucidate the conversion process of a NiFe2O4 anode and the capacity contribution from either Ni or Fe. Investigation reveals that the lithium extraction reaction does not fully agree with the previously reported one and is found to be a hindered oxidation of metallic nickel to nickel oxide in the applied potential window. Our findings suggest that iron is participating in an electrochemical reaction with full reversibility and forms iron oxide in the fully charged state, while nickel is found to be the cause of partial irreversible capacity where it exists in both metallic nickel and nickel oxide phases.