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Abstract Lithium-sulfur (Li S) batteries are attractive candidates for advanced energy storage devices. However, the low utilization of sulfur and the severe "shuttle effect" hinder the commercialization of Li S batteries. Herein, we design an ultra-thin and lightweight two-dimensional (2D) molybdenum nitride nanosheets layer to modify Celgard (denoted as MoN x /Celgard) separator to promote the electrochemical performance of Li S batteries. Benefiting from the 2D polar molybdenum nitride nanosheets, the obtained molybdenum nitride layer can effectively suppress the shuttle effect via the synergistic effect of structural confinement and chemical absorption. Meanwhile, molybdenum nitride nanosheets layer possesses metallic and catalytic characteristics, which are beneficial for high sulfur utilization. Therefore, the Li S batteries using MoN x /Celgard separator with multifunction exhibit high capacity and outstanding cycling performance. It delivers a high discharge capacity of 1298 mA h g−1 at 0.1C and sustain a capacity of 566 mA h g−1 after 500 cycles at 0.5C, corresponding with the capacity fading rate of only 0.063% per cycle. Highlights • A thin and lightweight 2D MoN x layer was introduced to modify Celgard separator. • Structural and chemical cooperativity of MoN x layer suppresses LiPSs' migration. • Metallic and catalytic properties of MoN x layer improve the sulfur utilization. • The Li S cell with MoN x /Celgard separator shows good electrochemical performance. [ABSTRACT FROM AUTHOR]

Abstract: Perovskite‐type solid‐state electrolytes exhibit great potential for the development of all‐solid‐state lithium batteries due to their high Li‐ion conductivity (approaching 10−3 S cm−1), wide potential window, and excellent thermal/chemical stability. However, the large solid–solid interfacial resistance between perovskite electrolytes and electrode materials is still a great challenge that hinders the development of high‐performance all‐solid‐state lithium batteries. In this work, a perovskite‐type Li0.34La0.51TiO3 (LLTO) membrane with vertically aligned microchannels is constructed by a phase‐inversion method. The 3D vertically aligned microchannel framework membrane enables more effective Li‐ion transport between the cathode and solid‐state electrolyte than a planar LLTO membrane. A significant decrease in the perovskite/cathode interfacial resistance, from 853 to 133 Ω cm2, is observed. It is also demonstrated that full cells utilizing LLTO with vertically aligned microchannels as the electrolyte exhibit a high specific capacity and improved rate performance. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are adopted to modify ZnCo 2 O 4 (ZCO) electrode, and a novel porous polyhedral structure ZCO/CNTs composites are prepared by a facile and scalable hydrothermal process, and the pure ZCO with cubic structure is also synthesized for comparison. The as-prepared materials are characterized by field emission scanning electron microscopy (FESEM). The results demonstrate that the introduced of CNTs has great effects on the nanostructure and electrochemical performance of the samples. The CNTs among the polyhedral structure ZCO/CNTs composites can provide better mechanical robustness, more contact between Li + and electrodes, and more effective electron transmission than the pure ZCO with cubic structure. When tested as anode materials for lithium ion batteries, the ZCO/CNTs composites exhibit a high initial coulombic efficiency of 83.9%, a high specific capacity of ∼864.6 mAh g −1 at a current rate of 100 mA g −1 after 150 cycles, as well as a good rate capability at elevated current rates, such as, ∼924.3 and ∼605.7 mAh g −1 at current rates of 500 and 2000 mA g −1 , respectively. This work would be meaningful in the preparation of complex oxides/carbon composites with porous nanostructure as anodes for LIBs. [ABSTRACT FROM AUTHOR]

Highlights: [•] The fiber bundle nanostructure ZnCo2O4 was prepared by co-precipitation method. [•] The as-prepared ZnCo2O4 electrode shows excellent electrochemical performances. [•] The preparation method has mild experiment conditions and high production rate. [ABSTRACT FROM AUTHOR]

• A novel quaternary, low-cobalt long-life LiNi 0.88 Co 0.06 Mn 0.03 Al 0.03 cathode is designed. • Zr-doping and LiBO 2 -coating measures are adopted to modify the LiNi 0.88 Co 0.06 Mn 0.03 Al 0.03. • The 18,650 full cell obtains capacity retention of 95.8% after 1000 cycles at 1C. Compared to the fossil-fuelled cars, developing a high-safety, low-cost, long-life lithium ion battery with higher energy density is critical important to enhance the market acceptance of electric vehicles. Herein, a novel quaternary low-cobalt LiNi 0.88 Co 0.06 Mn 0.03 Al 0.03 O 2 cathode material (NCMA-ZB) is rationally designed and synthesized by a two-step modification of Zr-doping and LiBO 2 -coating for the first time. Impressively, the two-step modified NCMA-ZB cathode exhibits greatly improved long-term cycling performance, voltage fading, high-temperature performance and safety performance. Further studies demonstrate that the two-step modification of Zr-doping and LiBO 2 -coating can remarkably strengthen the structural stability during the cell cycling. In addition, the thermal decomposition temperature of the modified NCMA-ZB cathode is increased by ∼8 ℃. Finally, the coin cells assembled by the as-prepared NCMA-ZB cathodes show a discharge specific capacity of 211.7 mAh g−1 and an initial coulombic efficiency of 89.0% at 0.1 C and 25 ℃ with a cut-off voltage range of 3.0–4.3 V. The corresponding capacity retention reaches 98.1% after 50 cycles at 1C. It additionally provides significantly improved high-temperature electrochemical performance of capacity retention of 97.8% after 50 cycles at 45 ℃. Moreover, the 18650-type cylindrical full cell configured with NCMA-ZB as the cathode obtains capacity retention of 95.8% after 1000 cycles at 1 C at 2.75–4.2 V. [ABSTRACT FROM AUTHOR]

In this paper, porous NiCo 2 O 4 @amorphous carbon (NCO@C) composites have been designed and fabricated via a sucrose-assisted hydrothermal method where sucrose act as carbon sources and chelating agent, followed by annealing in air atmosphere. The synthesized NCO@C composites exhibited porous, polycrystalline, and carbon-coated nature. When it was used as anode material for lithium-ion batteries, the porous NCO@C composite electrode delivered a high discharge specific capacity of 1224.8 mAh g −1 with 133.6% of the second reversible capacity over 190 cycles at a current density of 500 mA g −1 . Even at a current density as high as 4000 mA g −1 , a reversible capacity of 675.4 mAh g −1 was still obtained. The enhanced Li-storage performance should be attributed to the porous and firm nanostructure coated with a thin amorphous carbon layer (∼2 nm), as well as synergistic effects of NCO@C composites. [ABSTRACT FROM AUTHOR]

In this work, organic carbon modified NiCo 2 O 4 (NCO@C) nanocomposite with porous 3-dimensional (3D) structure was successfully synthesized by a facile hydrothermal method in D-glucose-mediated processes. A detailed research reveals that D-glucose molecules play an important role in the formation of the porous 3D structure and also provide a conductive carbon network within the NCO@C nanocomposite materials. Such a porous 3D interconnected carbonaceous nanostructure applied as electrode material for lithium-ion batteries (LIBs) shows that its reversible capacity, cycling stability, and rate capability are significantly enhanced in comparison with those of pure NiCo 2 O 4 (NCO) electrode. The as-prepared NCO@C composite electrode with porous 3D nanostructure displays a higher discharge specific capacity of 1389 mAh g −1 even after 180 cycles at a current rate of 0.55 C. Furthermore, this composite material also presents a high rate capacity, when the current rate gradually increases to 0.55 C, 1.1 C, 2.2 C, and 4.4 C, the reversible capacity can still render about 1082, 1029, 850, and 625 mAh g −1 , respectively. The enhanced electrochemical performance indicated that the NCO@C nanocomposite might be a very promising candidate to replace conventional graphite-based anode materials for LIBs. [ABSTRACT FROM AUTHOR]

Cubic spinel Co 2 SnO 4 /graphene sheets (Co 2 SnO 4 /G) nanocomposites are synthesized by a facile hydrothermal process in alkaline solution, using SnCl 4 · 4H 2 O, CoCl 2 · 6H 2 O and graphene oxide (GO) as the precursor. The structure and morphology of the resulting nanocomposites are characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Co 2 SnO 4 nanoparticles are uniformly dispersed among graphene sheets, with a size of 80–150 nm. As anode material for lithium-ion batteries, the galvanostatic charge/discharge and cyclic voltammetry are conducted to indicate the electrochemical performance of Co 2 SnO 4 /G nanocomposites. Co 2 SnO 4 /G nanocomposites exhibit an improved electrochemical performance compared with pure Co 2 SnO 4 nanoparticles, such as high reversible capacities, good cycling stability and excellent rate performance. The initial charge and discharge capacities are 996.1 mAh g −1 and 1424.8 mAh g −1 . After 100 cycles, the reversible charge/discharge capacities still remain 1046/1061.1 mAh g −1 at the current density of 100 mA g −1 . Co 2 SnO 4 nanoparticles coated by Graphene sheets with superior electrochemical performance indicate that Co 2 SnO 4 /G nanocomposites are promising electrode materials used for high-storage lithium-ion batteries. [ABSTRACT FROM AUTHOR]

A novel dispersed structure Co 2 SnO 4 /Co 3 O 4 composite has been successfully synthesized by a conventional co-precipitation method with certain amount of NaOH concentration. The obtained composite exhibits dispersed structure with small spherical nanocrystals adhering to the surface of large polyhedral particles, which has been studied as an anode material in lithium-ion battery. Galvanostatic charge–discharge and cyclic voltammetry has been conducted to measure the electrochemical properties of the material. The results show that Co 2 SnO 4 /Co 3 O 4 composite demonstrates good reversible capacity of 702.5 mA h g −1 after 50 cycles at a current density of 100 mA h g −1 , much better than that of pure Co 3 O 4 (375.1 mA h g −1 ) and pure Co 2 SnO 4 (194.1 mA h g −1 ). This material also presents improved rate performance with capacity retention of 71.1% when the current ranges from 100 mA g −1 to 1000 mA g −1 . The excellent electrochemical performance of the as-prepared dispersed structure Co 2 SnO 4 /Co 3 O 4 composite could be attributed to the good dispersibility of nanoparticles which can effectively alleviate the volume expansion and improve the conductivity, thus enhance the cycling stability. [ABSTRACT FROM AUTHOR]

Abstract: Chemical precipitation and hydrothermal reaction were adopted to prepare the SnO2 nanorods/MCMB composite. Firstly Mesophase carbon micro beads (MCMB) were treated by the mixture of concentrated sulphuric acid and nitric acid, and then deposited with a little amount of SnO2 though chemical precipitation to form the primitive SnO2/MCMB composite. In hydrothermal condition and at certain concentration of Na2SnO3, such primitive composite turned into the SnO2 nanorods/MCMB composite eventually. SEM figures showed that SnO2 nanorods grow on the surface of MCMB extensively; TEM and XRD characterization indicated SnO2 nanorods presenting good single crystalline structure with 50nm in diameter and 400–500nm in length. The following electrochemical performance showed that the final composite exhibited initial discharge capacity of 1321.25mAhg−1. Reversible capacity of 505.8mAhg−1 was observed after 50 discharge/charge cycles at the constant current density of 100mAg−1 etc. [Copyright &y& Elsevier]