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Because of sodium abundance, sodium ion batteries attract a lot of attention for advanced energy storage applications. As the main member of cathodes, NASICON-type structured Na 3 V 2 (PO 4) 3 contributes excellent ion shuttling rate and structure stability. However, the low electrical conductivity (<10−4 S cm−1) of Na 3 V 2 (PO 4) 3 limits its application in high power field. Herein, the Na 3 V 2 (PO 4) 3 nanoparticles anchored in the carbon matrix are successfully prepared through using the V-based metal organic frameworks (MIL-101(V)). As expected, these small Na 3 V 2 (PO 4) 3 grains are uniformly distributed in Na 3 V 2 (PO 4) 3 /carbon composite accompanying with the presence of 3D carbon framework. When used as cathode for sodium ion batteries, Na 3 V 2 (PO 4) 3 /carbon composite delivers a considerable Na-storage capacity of 136.4 mAh g−1 at the current rate of 1 C and in the voltage range of 2.5–3.8 V. Even at the current rate of 5 C and 10 C, the 84.17% and 84.5% of capacity retentions are surprisingly kept after 1,000 cycles, verifying its ultra-long cycling life. Electrochemical impedance spectroscopy substantiates a decreased charge transfer resistance for Na 3 V 2 (PO 4) 3 /carbon composite. Assisting with the detailed kinetic analysis, it is found that the enhanced surface-controlled behaviors mainly lead to the improvement of sodium-storage capability. The ex-situ scanning electron microscope and X-ray powder diffraction analysis demonstrates that unique architecture of as-prepared Na 3 V 2 (PO 4) 3 /carbon composite significantly enhances structural stability during the fast cycling. This work provides insights on design of future advanced electrode materials for sodium ion batteries. Image 1 • M-NVP/C composite is synthesized using MIL-101(V) as both carbon and vanadium source. • NVP nanoparticles are surrounded by 3D carbon framework and conductive network structure. • M-NVP/C composite demonstrates high-rate capability and long-term cyclability. • Pseudocapacitive behavior of M-NVP/C composite is confirmed by kinetics analysis. • Ex - situ SEM and XRD analysis proves the good structure stability of M-NVP/C composite. [ABSTRACT FROM AUTHOR]

An in situ SiC-TiB 2 ceramic composites was fabricated by infiltrating the Al-Si alloy melt into pre-sintered porous preforms with different B 4 C/TiC weight ratios. The phase composition and microstructure of the SiC-TiB 2 ceramic composites were analyzed to understand the synthesis mechanism of the composites. TiB 2 and SiC were originated from the reaction among B 4 C, TiC and Al-Si melt. When the B 4 C/TiC weight ratio was 35:65, the fabricated TiB 2 -SiC ceramic composites but no byproduct or raw powders displayed the optimal microstructure, and the TiB 2 and SiC particles were homogeneously distributed in Al-Si melt. The SiC-TiB 2 ceramic composites with the optimal microstructure owned the outstanding integrated mechanical properties: flexural strength of 245 MPa, fracture toughness of 4.32 MPa m1/2 and Vickers hardness of 10.46 GPa. The fracture surface of SiC-TiB 2 ceramic composites showed the mixed fracture mode with intergranular and transgranular fracture. The strengthening and toughening mechanisms were investigated from particle reinforcement, pulling out of grains and crack deflection found in the SiC-TiB 2 ceramic composites. • SiC-TiB 2 ceramic composite was creatively fabricated by RMI method through infiltrating Al-Si melt into pre-sintered porous TiC-B 4 C preform. • The optimal mechanical properties of SiC-TiB 2 ceramic composite was obtained when the weight ratio of B 4 C/TiC raw powder was 35:65. • The synthesis mechanism and fracture mode of the as-processed SiC-TiB 2 ceramic composite were discussed. [ABSTRACT FROM AUTHOR]

Taking advantage of the large surface area and high porosity characteristic of metal-organic framework (MOF) materials, the synthesis of carbon-coated bimetallic transition metal oxides stands out as an effective strategy to reduce volume expansion, enhance cycling stability, and improve electronic conductivity at the active sites in lithium-ion batteries (LIBs). In this research, a novel rambutan-like Ni-Co MOF was successfully synthesized via a hydrothermal method followed by calcination to obtain nitrogen-doped carbon-stabilized hierarchical rambutan-like NiCo 2 O 4 composites (NiCo 2 O 4 /NC). The resulting composites inherited the original rambutan-like structure of the Ni-Co MOF, which was characterized by uniform size, highly ordered porosity and large surface area, and showed excellent electrochemical Li+ storage performance. In particular, the NiCo 2 O 4 /NC-600 composite exhibited superior cyclic stability and rate capability, maintaining a remarkable reversible charge/discharge specific capacity of 1281.7/1292.7 mAh g−1 after 400 cycles at 0.5 A g−1. In addition, when paired with LiFePO 4 in a full cell, it maintained a reversible discharge specific capacity of 143.9 mAh g−1 after 200 cycles at 0.1 A g−1, indicating commendable cyclic stability. Ex-situ analyses confirmed the pseudo-capacitive behavior of the NiCo 2 O 4 /NC composites. Furthermore, the nitrogen-doped carbon layer embedded in the NiCo 2 O 4 /NC composites effectively mitigated the volume expansion during repeated Li stripping/plating processes, thereby improving the structural integrity, conductivity, and specific capacitance. This study presents a practical approach for fabricating nitrogen-doped carbon-stabilized bimetallic oxide anodes in high-power LIBs through architectural engineering and compositional tailoring. [Display omitted] • Hierarchical spherical NiCo 2 O 4 /NC composites by a facile MOF-derived oxidation method. • NiCo 2 O 4 /NC composites retained uniform size, well-ordered porosity and large surface area. • NiCo 2 O 4 /NC-600 composite showed excellent cyclic stability and rate performance. • The lithium storage mechanism of NiCo 2 O 4 /NC-600 composite was confirmed. [ABSTRACT FROM AUTHOR]

The objective of this paper is to prepare a series of spherical NiCo 2 S 4 materials coated with N-doped C (NiCo 2 S 4 /NC-400 °C, NiCo 2 S 4 /NC-450 °C and NiCo 2 S 4 /NC-500 °C) by calcining the precursor of NiCo-MOF (metal organic framework) at different temperatures, and to explore the applications as anode materials for lithium-ion batteries. The results showed that the electrochemical reaction mechanism of the three materials is conversion reaction. Compared with NiCo 2 S 4 /NC-400 °C and NiCo 2 S 4 /NC-450 °C, NiCo 2 S 4 /NC-500 °C exhibited excellent cycle performance and rate performance at different current densities. NiCo 2 S 4 /NC-500 °C has a minimum charge transfer resistance. In addition, the pseudocapacitance contribution rate was 67.1 % at the scanning speed of 0.5 mV s−1, as well as relatively good structural characteristics and small particle size. The results of this study provide a reference for the application of NiCo 2 S 4 /NC materials in lithium-ion batteries. • Spherical NiCo 2 S 4 coated with N-doped C is prepared by calcining the precursor of NiCo-MOF. • N-doped C leads to good structural characteristics, small particle size and increases the intrinsic conductivity. • NiCo 2 S 4 /NC-500 °C demonstrates the best specific discharge/charge capacities and rate performance. • The conversion reaction mechanism of NiCo 2 S 4 /NC is revealed. [ABSTRACT FROM AUTHOR]

• Na 2 Ti 6 O 13 nanorods are prepared by the hydrothermal and solid-phase sintering methods. • Na 2 Ti 6 O 13 nanorods has large interlayer spacing (about 0.798 nm). • Na 2 Ti 6 O 13 nanorods exhibit high cycle capacity and high rate capability. • The pseudo-capacitance contribution rate and Na+ diffusion coefficient are calculated. [Display omitted] In this study, Na 2 Ti 6 O 13 nanorods with large interlayer spacing (about 0.798 nm) were synthesized by the hydrothermal and solid-phase sintering methods, and applied to the anode of sodium ion batteries (SIBs). The influence of different calcination temperatures on the electrochemical properties of Na 2 Ti 6 O 13 nanorods were all studied. Benefitting from the nanorods structure and the large interlayer spacing, the Na 2 Ti 6 O 13 prepared at 800 °C possessed fast Na+ diffusion and achieved high discharge capacities of 168.2 and 115.2 mA h g−1 at different current densities of 20 and 500 mA g−1, respectively, and remained at 131.1 and 96.7 mA h g−1 after 100 cycles, which exhibited the best cycling stability, fast Na+ diffusion characteristics, and excellent rate performance. Supported by electrochemical impedance spectroscopy, we found that the value of R ct became larger and the D Na + became smaller with the progress of charge and discharge, which might be the cause of the decrease in the specific discharge capacity. The detailed analysis of cyclic voltammetry test confirmed that the proportion of pseudo-capacitance gradually decreased with the electrochemical reaction process keeping, from 83.8% at the beginning to 60.9% at the 100th cycle. This work establishes a valuable basis for the future study of Na 2 Ti 6 O 13 as outstanding anode material for SIBs. [ABSTRACT FROM AUTHOR]

• NVO material doped by niobium ion (Nb5+) was successfully prepared by the rheological phase method. • Nb-doping lead to an expansion of the lattice volume and increase the intrinsic conductivity. • NaNb 0.018 V 2.982 O 8 demonstrates high-rate capability and long-term cyclability. • Pseudocapacitive behavior of Nb-doped NVO is confirmed by kinetics analysis. In this work, NaNb 0.018 V 2.982 O 8 (NVO-0.018Nb) composite was served as the cathode of sodium-ion batteries (SIBs) to deliver a superior Na-storage capacity of 187 mA h g−1 at the current density of 1 C and voltage range of 1.5–4.0 V, and favorable energy density (419.3 Wh kg−1). Electrochemical impedance spectroscopy (EIS) measurements displayed decreased charge transfer resistance in the NVO-0.018Nb composite. The detailed kinetic analysis revealed enhanced surface-controlled behaviors, leading to improved sodium-storage capability. Scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) analyses demonstrated that NVO-0.018Nb composite exhibited unique structure with significantly enhanced structural stability during fast cycling. In sum, the proposed method looks promising for the design of future advanced electrode materials of SIBs. [ABSTRACT FROM AUTHOR]

Four layered quaternary sulfides KAgCdS 2 (1), RbAgCdS 2 (2), CsAgCdS 2 (3), and Cs 2 Cu 2 Cd 2 S 4 (4) have been successfully synthesized by mild solvothermal methods by employing excess sulfur as a mineralizer. Compound 1 possesses anionic [AgCdS 2 ] n n− double layers. Compounds 2 and 3 are isostructural and contain anionic [AgCdS 2 ] n n− single layers. Although both of the two structures are constructed by edge-sharing [MS 4 ] (M = Ag/Cd) tetrahedral units, their condensation behaviors are totally different. The structure of 4 consists of infinite [Cd 2 S 4 ] n 4n− chains and [CuS 2 ]2- dumbbells that linked to form [Cu 2 Cd 2 S 4 ] n 2n− layers. According to the UV–vis diffuse reflectance experiments, the band gaps of the title compounds are 1.92 eV (1), 2.16 eV (2), 2.42 eV (3), and 2.23 eV (4). Additionally, the photoelectrochemical experiments indicate that compounds 2 and 3 exhibit excellent photocurrent responsive properties. Image 1 • Compounds KAgCdS 2 (1), RbAgCdS 2 (2), CsAgCdS 2 (3), and Cs 2 Cu 2 Cd 2 S 4 (4) were synthesized by solvothermal methods. • Excess sulfur was firstly extended to the mineralizing of quaternary sulfides containing two late transition metals. • Compounds RbAgCdS 2 (2) and CsAgCdS 2 (3) exhibit excellent photocurrent responsive properties. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) have garnered significant academic and industrial focus because of their excellent merits, like high voltage, high energy density, excellent cyclic performance, no memory effect and environment-friendly nature. So far, the electrochemical properties of LIBs are restricted by the capacity of cathode materials and various novel compositions and designed architectures have been proposed to enhance the energy density and cyclic performance of LIBs cathodes. Recently, lithium nickel cobalt manganese oxides have attracted extensive research interest owing to the united advantages of LiCoO 2 , LiNiO 2 and LiMnO 2. Herein, we have reviewed the recent developments of LiNi 1/3 Co 1/3 Mn 1/3 O 2 from the viewpoint of synthesis processes and structural designs. The electrochemical properties of LiNi 1/3 Co 1/3 Mn 1/3 O 2 depend on particle size, morphology, ion doping and surface coating of the as-prepared cathode powder. The present article summarizes the recent developments and provides an insight into the future roadmap for the realization of high energy density LIBs. • Main synthesis methods of NCM cathodes are summarized and analyzed. • Partial ionic substitution enhances the structural stability and electronic conductivity. • Surface coating can prevent the side reactions, improved the electronic and ion migration rate. • Composite structure can increase the structure constancy and the electronic conductivity. [ABSTRACT FROM AUTHOR]