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Layered O3-phase LiNi0.8Co0.1Mn0.1O2 (NCM811) material has shown great potential for lithium-ion batteries (LIBs). However, capacity attenuation and irreversible phase transitions have been serious...

A Ti-34Nb-13Ta-5Zr (TNT5Zr) β Ti alloy with a high strength-to-modulus ratio has been developed, showing its potential to become another candidate material in load-bearing implant applications. This work mainly investigates the microstructural evolution, mechanical properties, and biocompatibility of a post-processing-treated TNT5Zr alloy manufactured via selective laser melting (SLM). Transmission electron microscopy observation shows the existence of the single beta grain matrix and alpha precipitates along the grain boundary in the SLM + HIP manufactured TNT5Zr alloy (TNT5Zr-AF + HIP), and ellipsoidal nano-sized intragranular α″ precipitates (approx. 5-10 nm) were introduced after the subsequent low-temperature aging treatment. The precipitation strengthening enables the SLM + HIP + aging manufactured TNT5Zr (TNT5Zr-AF + HIPA) alloy to show a comparable ultimate tensile strength (853 ± 9 MPa) to that of the reference material (Ti64-AF + HIP, 926 ± 23 MPa). Including the inferior notch-like surface of the test pieces, the slip-band cracking that occurs in this ductile TNT5Zr-AF + HIPA alloy is regarded as the main factor in determining its fatigue strength (170 MPa).

O3-NaNi0.33Mn0.33Fe0.33O2 layered oxide has attracted increasing attention as one of the most promising materials for Na-ion battery applications due to air stability and environmental friendliness, but the complex phase transitions and inferior cycling stability are extremely challenging to overcome. Cation substitution has been widely used to stabilize crystal structures and improve electrochemical performance for SIBs. Based on past experimental results, it was discovered that the transition metal–oxygen bond energy of the introduced dopant is an important factor for optimizing electrochemical performance. In this study, we validated our hypothesis that yttrium (Y)-which possesses high bond energy for oxygen-is most likely to be an ideal doping element by conducting a comparative study of substituting Mn in O3-NaNi0.33Mn0.33Fe0.33O2 layered oxide with aluminum (Al) and Y through elemental doping. As hypothesized, the electrochemical properties of NaNi0.33Mn0.33Fe0.33O2 have increased markedly by introducing a small amount of Y and Al, and the Y-doped materials showed superior rate performance and cycling stability due to enhanced Na+ diffusion reaction kinetics and layered structure stability. Furthermore, the substitution of Y for Mn can improve thermal stability and alleviate phase transformations. The improvement mechanism of Y substitution can be attributed to a larger d-spacing and stronger metal–oxygen bond. These results suggest that structural modulation is an effective strategy to reinforce electrochemical properties of layered oxides and provides some guidance about designing promising electrode materials.

The P2-type layered oxide Na2/3[Ni1/3Mn2/3]O2 cathode material is considered a promising material for sodium-ion batteries because of its high capacity and operating voltage together with a simple ...

Nickel-rich cathode materials have attracted considerable interest because of their high specific capacities, voltage ranges, and low cost. However, serious capacity attenuation and poor rate performance limit their application. This study proposes a novel strategy to improve the cycle stability of the nickel-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) layer material by designing core-shell LiNi0.8Co0.1Mn0.1O2 (CS-NCM811). CS-NCM811 is designed by the characteristic reaction between dimethylglyoxime (C4H8N2O2) and nickel ion to form Ni(C4H7N2O2)2. The CS-NCM811 is characterized with high nickel content in its core and high manganese content on its surface, leading to a high capacity and excellent cycle stability. The capacity retention of CS-NCM811 was 72.8%, much higher than that of NCM811 (47.1%) after 500 cycles at a rate of 5 C. Not only is this method a novel strategy to design high capacity cathode materials but also provides some new insights into the cycle stability of nickel-rich layered cathode materials.

Layered oxide O3-NaNi1/3Mn1/3Fe1/3O2 is one of the most promising cathode materials with high open-air stability, low cost, and environmental friendliness, but it experiences a series of complicated phase transitions during the charge-discharge process that lead to inferior electrochemical properties. In this work, we find that phase transitions of O3-NaNi1/3Mn1/3Fe1/3O2 can be effectively suppressed through in situ coating of Na-ion conductor Na2SiO3. The Na2SiO3 coating layer can reduce polarization and suppress voltage drop, and also has three-dimensional pathways for Na-ion diffusion to ensure larger Na+ diffusion coefficient. Therefore, the electrochemical performances of layered oxide NaMO2 (M = Ni1/3Mn1/3Fe1/3) can be greatly improved. Specifically, the discharge capacity of 5 mol% Na2SiO3 coated electrodes increase by 28% compared to the pristine after 50 cycles. Na2SiO3 coated NaNi1/3Mn1/3Fe1/3O2 also shows outstanding rate capability (58 mAh g−1 at a high rate of 5 C, compared to only 12 mAh g−1 for the pristine). These results suggest this to be an effective and reliable surface-modification strategy to reinforce the electrochemical properties of layered oxide materials for sodium ion batteries.

Layered P2-type CuO-coated Na2/3[Ni1/3Mn2/3]O2 (NNMO@CuO) with excellent rate capability and cycling performance was investigated as a sodium-ion battery cathode material for the first time. The NNMO@CuO cathode material combines the advantages of CuO coating and Cu2+ doping. Transmission electron microscopy (TEM) images, TEM elemental line scan analysis and ex situ scanning electron microscopy (SEM) images show that CuO has been successfully coated on the particle surface uniformly, and that this CuO layer effectively suppresses the exfoliation of the metal oxide layers and unfavorable side reactions. Furthermore, Cu2+ is also partially incorporated into the host structure, according to the X-ray diffraction (XRD) patterns and refinement results. Although incorporated Cu2+ does not take part in the redox reactions of the battery cell, the refinement results indicate that the d-spacing of the Na+-ion diffusion layer is enlarged due to Cu2+ doping in the crystal structure, which results in better Na+ kinetics. Thus, the CuO-coated cathode material shows prominent cycling performance and rate capability. We believe that this CuO-coating and Cu2+-doping co-modification strategy provides a promising approach to designing advanced cathode materials for sodium-ion batteries.

Sodium-ion batteries (SIBs) have shown great superiority for grid-scale storage applications because of their low cost and the abundance of sodium. P2-type Na2/3Ni1/3Mn2/3O2 cathode materials have attracted much attention for their high capacities and operating voltages as well as their simple synthesis processes. However, Na+/vacancy ordering and the P2-O2 phase transition are unavoidable during Na+ insertion/extraction, leading to undesired voltage plateaus and deficient battery performances. We show that this defect can be effectually eliminated by coating a moderate Na+ conductor Na2Ti3O7 with a smart in situ coating approach and a concomitant doping of Ti4+ into the bulk structure. Based on the combined analysis of ex situ X-ray diffraction, scanning electron microscopy, electrochemical performance tests, and electrochemical kinetic analyses, Na2Ti3O7 coating and Ti4+ doping effectively refrain Na+/vacancy ordering and P2-O2 phase transition during cycling. Additionally, the Na2Ti3O7 coating layer suppresses particle exfoliation and accelerates Na+ diffusion at the cathode and electrolyte interface. Hence, Na2Ti3O7-coated Na2/3Ni1/3Mn2/3O2 exhibits excellent cycling stability (almost no capacity decay after 200 cycles at 5 C) and outstanding rate capability (31.1% of the initial capacity at a high rate of 5 C compared to only 10.4% for the pristine electrode). This coating strategy can provide a new guide for the design of prominent cathode materials for SIBs that are suitable for practical applications.

Objective: Based on GEO database, we performed bioinformatics analysis on rheumatoid arthritis (RA)-related gene chips to obtain key genes and signaling pathways of RA, understand the molecular mechanism of RA occurrence and development, and provide candidate targets for the diagnosis and treatment of RA.Methods: The chip GSE77298 related to rheumatoid arthritis in GEO database was retrieved, and the R Programming Language analyzed the differential genes. Subsequently, the differential gene protein-protein interaction (PPI) relationship was constructed. The hub gene was screened, and the DAVID database was used for GO enrichment analysis and KEGG pathway analysis of key differential genes. The miRNAs were then subjected to target gene prediction, and then a miRNA-mRNA visualization network map was constructed using Cytoscape. Finally, transcription factors were predicted by the AnimalTFDB database.Results: ①The chip with the serial number of GSE77298 was retrieved from GEO database, and 1539 differential genes were screened out using the R Programming language analysis, including 1156 up-regulated genes and 383 down-regulated genes. ②By DAVID online functional enrichment analysis of differential genes, it was shown that the signaling pathways were mainly rheumatoid arthritis, Staphylococcus aureus infection, chemokine signaling pathway, viral myocarditis, cytokine-cytokine receptor interaction, etc. ③PPI was constructed through String database. Its hub genes were CXCL12, CD44 and CDH2. The top 10 key differential genes in Degree were CXCL8, PTPRC, MMP9, TLR2, FN1, ITGB2, CXCL1, CCL5, CXCR4 and CXCL10. ④Ten important miRNAs such as hsa-miR-30a-3p, hsa-miR-34a-5p, hsa-miR-30d-3p were predicted. ⑤Transcription factors such as GTF3C2, GLYR1, TRIM24, YY1 were predicted.Conclusion: PI3K-AKT signaling pathway and many other pathways are involved in the occurrence and development of RA, and CXCL8, SOCS3, and TLR2 genes may be the key genes in RA. Ten important miRNAs such as has-miR-340-5p may participate in the pathogenesis of RA. Many transcription factors such as YY1 may be involved in RA's disease process, which will provide directions for further research on RA diagnosis and treatment targets of RA.

This study investigates Ti-Nb-Ta based β alloys with different zirconium additions (0, 5, 9 wt%) manufactured by SLM. A low level of as-fabricated defects is obtained: the relative density of TNT (Z) alloys is99.97% with the keyhole size in a range of 3-20 μm. BF TEM images combining SAD patterns of TNT(Z) alloys show single β phase obtained inside the beta matrix; BF-STEM images reveal potential nano-scale grain boundary alpha phase precipitation. Zirconium functions as a neutral element in these high β-stabilized Ti-Nb-Ta based alloys. An increase in Vickers hardness and UTS caused by zirconium additions is observed, which is explained by beta grain refinement because higher degree of undercooling occurs. Corrosion ions of TNT(Z) alloys released from immersion testing at each time intervals show extremely small concentrations (10 μg/L). It indicated that good biocompatibility during culture with the negligible corrosion ions. High strength-to-modulus ratio β Ti alloys together with excellent biological response show their prospect for biomedical applications.

O3-NaNi0.33Mn0.33Fe0.33O2 layered oxide has attracted increasing attention as one of the most promising materials for Na-ion battery applications due to air stability and environmental friendliness, but the complex phase transitions and inferior cycling stability are extremely challenging to overcome. Cation substitution has been widely used to stabilize crystal structures and improve electrochemical performance for SIBs. Based on past experimental results, it was discovered that the transition metal-oxygen bond energy of the introduced dopant is an important factor for optimizing electrochemical performance. In this study, we validated our hypothesis that yttrium (Y)-which possesses high bond energy for oxygen-is most likely to be an ideal doping element by conducting a comparative study of substituting Mn in O3-NaNi0.33Mn0.33Fe0.33O2 layered oxide with aluminum (Al) and Y through elemental doping. As hypothesized, the electrochemical properties of NaNi0.33Mn0.33Fe0.33O2 have increased markedly by introducing a small amount of Y and Al, and the Y-doped materials showed superior rate performance and cycling stability due to enhanced Na+ diffusion reaction kinetics and layered structure stability. Furthermore, the substitution of Y for Mn can improve thermal stability and alleviate phase transformations. The improvement mechanism of Y substitution can be attributed to a larger d-spacing and stronger metal-oxygen bond. These results suggest that structural modulation is an effective strategy to reinforce electrochemical properties of layered oxides and provides some guidance about designing promising electrode materials.

Nickel-rich layered cathode materials have aroused widespread interest due to their high discharge capacity, which is a basic requirement for next-generation high energy density lithium batteries. However, with the increase of nickel content, cathode materials face the serious challenge of capacity degradation, which is attributed to the formation of rock salt-type oxides such as NiO on the surface of cathode particles. To overcome this shortcoming, a novel Ni concentration gradient LiNi0.8Co0.15Al0.05O2 (NCG-NCA) cathode material was successfully synthesized using the characteristic reaction of Ni2+ and dimethylglyoxime. The final synthesized nickel concentration gradient material combines the advantages of high discharge capacity and excellent stability, which are attributed to the high nickel content in the core and high cobalt content on the surface of the material particles. The cycling stability of the NCG material is remarkably improved, exhibiting an excellent capacity retention of 75% after 200 cycles at a current density of 10C (1C = 160 mA g-1) under a high cut-off voltage of 4.5 V, much higher than that of a pristine NCA (P-NCA) cathode without NCG (50%). The excellent cycling stability of NCG-NCA is due to formation of a stable surface, which is not prone to serious atomic rearrangement on the surface. More importantly, with the structural analysis of NCA materials by neutron diffraction, we find that the proportion of Li/Ni mixing of NCA is reduced by utilizing the NCG structure; in turn, the rate performance of NCG-NCA cathode materials is improved greatly.

The poor rate performance and low discharge capacity of LiCoO2 limit its applications. Therefore, in this work, we synthesized Li1-xMxCoO2 (M = Na, Zr, Nb) via solid-phase synthesis to improve its properties. X-ray diffraction (XRD) results suggest that the doping elements were successfully doped into LiCoO2. The electrochemical properties showed that the samples doped with the high-valence elements Zr and Nb had a higher capacity, better cycle stability, and better rate performance than those doped with the low-valence element Na. In particular, the capacity retention of LiCoO2, Li0.97Na0.03CoO2, Li0.99Zr0.01CoO2, and Li0.99Nb0.01CoO2 was 68, 42, 85, and 87%, respectively, after 80 cycles at a rate of 10 C at 55 °C. However, doping of Zr and Nb into the Li+ site of LiCoO2 will reduce the content of Li+. And, less Li+ extracted in the cathode material resulting in low discharge capacity under low current density. The larger radius of Na+ is incorporated into the Li slab and enlarged the interlayer spacing of the (003) plane. The larger (003) interplanar spacing can significantly facilitate the lithium diffusion and is also favorable to the rate capability. The differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis results demonstrated that the Zr-doped and Nb-doped LiCoO2 had a higher thermal stability in the charged state than the Na-doped LiCoO2. Additionally, the resistances of the Zr-doped and Nb-doped electrodes were much lower than that of the undoped electrode. Our research results indicate that doping with high-valence elements is a very effective strategy for optimizing the electrochemical performance of LiCoO2 and that this method can also be extended to other cathode materials.

High-nickel materials with core–shell structures, whose bulk is rich in nickel content and the outer shell is rich in manganese content, have been demonstrated to improve cycle stability. The high-nickel cathode material LiNi0.8Co0.1Mn0.1O2 is a very promising material for lithium-ion batteries; however, its low rate performance and especially cycle performance currently hamper further commercialization. This study presents a new synthesis method to prepare this core–shell material (LiNi0.8Co0.1Mn0.1O2@x[Li–Mn–O], x = 0.01, 0.03, 0.06). Electrochemical data show that LiNi0.8Co0.1Mn0.1O2@x[Li–Mn–O] (x = 0.03, CS-0.03) exhibits the best high-rate performance, cycle stability, and thermal stability. The initial discharge capacity of the core–shell sample CS-0.03 is 118 mAh g–1, which is almost the same as the discharge capacity of pristine LiNi0.8Mn0.1Co0.1O2 (117 mAh g–1) at the rate of 10 C in the voltage range of 3.0–4.3 V. Notably the capacity decay of CS-0.03 is 18.4% after 200 cycles compared to 27% de...

In our work, a series of Li 1-x M x CoO 2 (M = Na, x = 0–0.05) samples are synthesized by the solid-state calcination route. Electrochemical measurements show that high-rate capacities and high-voltage performances receive obvious improvements with an appropriate content of Na-doping. Specially, the capacity retentions of Li 0.97 Na 0.03 CoO 2 and LiCoO 2 are 65.6% and 62.7% after the 100 th cycle at 3.0–4.5 V, respectively. The discharge capacity of Li 0.97 Na 0.03 CoO 2 compared with the pristine electrode LiCoO 2 is greatly enhanced from 125 to 135 mAh·g −1 at the rate of 5 C and 98 to 120 mAh·g −1 at the rate of 10 C (1C = 140 mA g −1 ) respectively. With the larger radius of Na + substituted for the smaller radius of Li + , it is found that the bond length of Li O is reduced from 2.0801 A to 2.0781 A, which is helpful for stabilizing the structure of LiCoO 2 and improving the cycle capability at high voltages. At the same time, the inter-planar distance of Li slabs is expanded from 2.5904 A to 2.59511 A which can accelerate the diffusion of Li + and improve the rate capacity. Therefore, Na-doped LiCoO 2 shows outstanding high-voltage and high-rate performances, and the strategy can also be popularized and applied to other layered cathodes.

Novel three-dimensional ZnAl-LDH/AAO and NiAl-LDH/AAO membranes using porous anodic aluminum oxide (AAO) templates as a substrate and an Al3+ source were successfully fabricated via a simple precipitant-free in situ growth technique. These membranes with uniform layered double hydroxide (LDH) plates on the outer and inner surfaces exhibit enhanced activities in photocatalysis.

As a promising cathode material, the layered oxide P2-Na0.67Fe0.5Mn0.5O2 has the obviously advantage of environmental friendliness, low cost and high theoretical capacity (290 mAh g−1), but the unfavored phase transitions lead to fast capacity decay during charge and discharge process. Surface modification and element substitution of cathode materials are emphasized for guaranteeing excellent electrochemical performance. Herein, we propose a collaborative strategy that the surface of layered P2-Na0.67Fe0.5Mn0.5O2 modified with conducting ionic Na2SiO3 nanolayers, 4.06 nm in thickness, which can inhibit side effects between the material and the electrolyte, ensure Na-ion diffusion coefficient, reduce the polarization and improve the cycling stability of the material. Furthermore, the partial element substitution of Si4+ during the coating process can be conducive to the extraction and embedding of sodium ions and able to stabilize the crystal structure of the materials resulting from a smaller radius of Si4+ and a higher bond energy of Si-O, which can enhance rate performance and thermal stability of the cathode materials. Above all, the collaborative strategy with ionic conductive Na2SiO3 coating and Si doping is reliable and effective to display preferable electrochemical properties for sodium-ion batteries.

According to the working principle of Lithium ion batteries, a perfect coating layer should not only be a lithium ion conductor but also an electronic conductor. In this work, the layered cathode material LiNi1/3Mn1/3Co1/3O2 was modified by a dual functional coating layer created from the Li-ion conductor Li2SiO3 and electronic conductor carbon. It was found that the modified LiNi1/3Mn1/3Co1/3O2 showed outstanding electrochemical performance after being coated with an appropriate content of Li2SiO3&C. Particularly, at the high current density of 5C (1C = 160 mA/g), the LiNi1/3Mn1/3Co1/3O2 coated with Li2SiO3&C could still deliver a discharge capacity of 96 mAh/g after 500 cycles with a capacity retention of 89.62%. In comparison, the pristine only delivered a discharge capacity of 71 mAh/g after 450 cycles. Furthermore, our strategy is convenient and universal, it can also be applied to other layered cathode materials to ameliorate their electrochemical properties.

Crystal structures and thermal expansion properties of Yb 2− x Fe x Mo 3 O 12 ( x = 0.0, 0.6, 1.0, 1.1, 1.4) solid solutions have been studied by X-ray powder diffraction (XRPD) at different temperatures. Rietveld analysis of the XRPD data shows that Yb 2− x Fe x Mo 3 O 12 solid solutions adopt orthorhombic structure and have variable thermal expansion coefficients controlled by the ratio of Yb 3+ to Fe 3+ . Yb 2 Mo 3 O 12 shows anisotropic negative thermal expansion property, induced by the reductions in average Yb–O–Mo angle and average apparent Mo2–O bond length with increasing temperatures. As more Yb 3+ substituted by Fe 3+ , the linear thermal expansion coefficients of Yb 2− x Fe x Mo 3 O 12 increase from negative to positive. A near-zero thermal expansion coefficient of 0.55 × 10 −6 K −1 for Yb 0.6 Fe 1.4 Mo 3 O 12 is observed in the temperature range of 573–873 K

Decreasing Li/Ni disorder has been a challenging problem for layered oxide materials, where disorder seriously restricts their electrochemical performances for lithium-ion batteries (LIBs). Element...

A series of LiNi0.5-x Mg x Mn0.5O2 (0 ≤ x ≤ 0.1) samples are synthesized by a combination of coprecipitation (CP) and solid-state reaction. After electrochemical measurements, the discharge capacity and cycle stability of LiNi0.5Mn0.5O2 can be obviously improved by Mg doping and the best doping amount is 5%. Most importantly, the cycle stability of LiNi0.5Mn0.5O2 at high voltage can be greatly improved by Mg doping. Specifically, capacity retention of 5% Mg-doping sample improves 16% than that of pure LiNi0.5Mn0.5O2 in the range of 3.0 ~ 4.6 V. We find Mg doping can lower the Li/Ni cation mixing, reduce migration resistance, and retard polarization, in turn, improve the electrochemical properties of LiNi0.5-x Mg x Mn0.5O2.

A high cut-off voltage is pretty pivotal for the improvement of the energy density of cathode materials. Unfortunately, high-capacity Ni-rich cathode materials usually show serious capacity attenuation at high cut-off voltage. Herein, we propose a Li2SiO3-surface modification strategy to highly improve the cycle performance of the Ni-rich LiNi0.8Mn0.1Co0.1O2 material at high voltage. The capacity retention of the pristine and Li2SiO3-coated electrodes is 57.6 and 77.7%, respectively, at the cut-off voltage of 4.6 V after 50 cycles. Meanwhile, the problems of polarization and voltage reduction of LiNi0.8Mn0.1Co0.1O2 are also alleviated. Our results show that Li2SiO3-surface modification is a very effective strategy for improving the cycle stability of Ni-rich cathode materials and can be used for other high capacity electrode materials.

Although layered cathode materials LiNixMnyCo1−x−yO2 have attracted much attention due to their number of advantages, the issue of Li/Ni disorder seriously restricts their electrochemical properties. It is very important and pivotal for the better optimization of layered cathode materials to clearly explain the detailed relationships among the Li/Ni disorder, Li+ migration resistance, electrochemical kinetics and electrochemical properties. Here we focus on the LiNixMnyCo1−x−yO2 cathode material and report relationships among the crystal structures, Li+ migration resistance, electrochemical kinetics and electrochemical properties by combining neutron diffraction techniques, electrochemical kinetic analysis techniques and first-principles calculation methods. The results suggest that more Li+/Ni2+ ion exchange will shrink the inter-slab space thickness, causing a higher Li+ ion migration barrier and inferior electrochemical kinetics, all of which should be responsible for the limited electrochemical properties.

Sodium-ion batteries (SIBs) have shown great superiority for grid-scale storage applications because of their low cost and the abundance of sodium. P2-type Na

Layered P2-type CuO-coated Na2/3[Ni1/3Mn2/3]O2 (NNMO@CuO) with excellent rate capability and cycling performance was investigated as a sodium-ion battery cathode material for the first time. The NNMO@CuO cathode material combines the advantages of CuO coating and Cu2+ doping. Transmission electron microscopy (TEM) images, TEM elemental line scan analysis and ex situ scanning electron microscopy (SEM) images show that CuO has been successfully coated on the particle surface uniformly, and that this CuO layer effectively suppresses the exfoliation of the metal oxide layers and unfavorable side reactions. Furthermore, Cu2+ is also partially incorporated into the host structure, according to the X-ray diffraction (XRD) patterns and refinement results. Although incorporated Cu2+ does not take part in the redox reactions of the battery cell, the refinement results indicate that the d-spacing of the Na+-ion diffusion layer is enlarged due to Cu2+ doping in the crystal structure, which results in better Na+ kinetics. Thus, the CuO-coated cathode material shows prominent cycling performance and rate capability. We believe that this CuO-coating and Cu2+-doping co-modification strategy provides a promising approach to designing advanced cathode materials for sodium-ion batteries.

The spherical-like θ-Al45(Mn,Cr)7 particle having a monoclinic structure is observed in an Al–Mg alloy using TEM. Two types of twins with different twin directions are found in these θ-Al45(Mn,Cr)7 particles. One type is shown to be a ( 1 ‾ 11 ) twin with ( 1 ‾ 11 ) plane serving as the twinning plane and the shear direction is η1 = [ 1 2 ‾ 3 ] ; the other type is seen to be a ( 1 ‾ 10 ) orientation twin with ( 1 ‾ 10 ) plane acting as the coherent plane. At least six different orientation relationships between the θ-Al45(Mn,Cr)7 particles and the α-Al matrix are observed. These relatively complicated orientation relationships are attributed to the pseudo ten-fold symmetric building block of the θ phase viewed along the [101] axis. The possible formation mechanisms of these twins are discussed based on a crystallographic consideration.

Ni-rich materials are among the most promising cathode materials for use in the electric vehicle industry with high energy density, excellent low temperature performance and rate performance. However, with the increase of Ni content, many problems emerge in Ni-rich materials, such as residual alkali and the side reactions at the electrode surface. In this work, we find that part of the residual lithium at the surface of the Li[Ni0.8Co0.1Mn0.1]O2 material can be converted into lithium silicate as a lithium-ion conductor, through the surface treatment of tetraethyl orthosilicate, thereby solving the above problems. Specifically, at a rate of 3C, the material with a coating amount of 2 wt% showed a capacity retention rate of 83.33% after 300 cycles, with the pristine material at only 64.60%. Furthermore, under the protection of the coating layer, the dissolution of the transition metal and side reactions on the cathode electrode surface were effectively suppressed. Experimental results proved that this method is reliable and easy to implement and can serve as a comprehensive solution for common problems of Ni-rich materials.

The Li2MnO3 coated LiNi0.8Mn0.1Co0.1O2 electrode has been sucessfully synthesized through a PVP-chelation and syn-lithiation strategy. X-ray diffraction (XRD) and X-ray photoelectron Spectrometer (XPS) characterizations are applied to verify the existence of the Li2MnO3 surface layer. The complete and nanoscale Li2MnO3 coating layer strongly adheres to the host material because of the layered/layered homostyructure, improves the content of Mn element on the surface of the electrode and has three-dimensional path for Li+-ion diffusion. Due to the numerous unique and dramatic advantages of the Li2MnO3 surface layer, the layered/layered homostyructure electrode exhibits superior cycle stability, rate capability and other electrochemical properties. The newly developmental coating material and versatile nanocoating strategy can also be popularized and applied in other electrode materials.

This work provides a convenient, effective and highly versatile coating strategy for the layered oxide LiMO2 (M = Ni0.5Mn0.5 and Ni1/3Mn1/3Co1/3). Here, layered oxide LiMO2 (M = Ni0.5Mn0.5 and Ni1/3Mn1/3Co1/3) has been successfully coated with ion conductor of Li2SiO3 by in situ hydrolysis of tetraethyl orthosilicate (TEOS) followed by the lithiation process. The discharge capacity, cycle stability, rate capability, and some other electrochemical performances of layered cathode materials LiMO2 can be highly enhanced through surface-modification by coating appropriate content of Li2SiO3. Particularly, the 3 mol % Li2SiO3 coated LiNi1/3Mn1/3Co1/3O2 exhibits approximately a discharge capacity of 111 mAh/g after 300 cycles at the current density of 800 mA/g (5 C). Potentiostatic intermittent titration technique (PITT) test was carried out to investigate the mechanism of the improvement in the electrochemical properties. The diffusion coefficient of Li+-ion (DLi) of Li2SiO3 coated layered oxide materials has b...

High-nickel materials with core-shell structures, whose bulk is rich in nickel content and the outer shell is rich in manganese content, have been demonstrated to improve cycle stability. The high-nickel cathode material LiNi