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Abstract: Li2FeSiO4/C composites were successfully prepared by tartaric acid assisted sol–gel route. Tartaric acid was used as both the chelating agent and carbon source. Effects of carbon content on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge–discharge and AC impedance spectroscopy, respectively. The particle size of Li2FeSiO4/C decreases with increasing content of carbon; however higher content of carbon will lead to poorer crystallinity and more impurities. When the carbon content is 4.0wt.%, the Li2FeSiO4/C sample has the largest exchange current density (i° =0.110mAcm−2) and highest diffusion coefficient of lithium ion (D Li + =1.01E−12cm2 s−1). Thus, Li2FeSiO4/C with 4.0wt.% carbon has the best electrochemical properties, in terms of discharge capacity and cycling stability. It exhibits an initial discharge capacity of 119.7mAhg−1 at C/16 rate at room temperature. When cycled at C/10 rate, the Li2FeSiO4/C sample with 4.0wt.% carbon delivers an initial discharge capacity of 96.6mAhg−1, and 98.6% of the initial discharge capacity remained after 25 cycles. [Copyright &y& Elsevier]

A high-rate and stable-cycling hollow corn-like LiNi 0.8 Co 0.1 Mn 0.1 O 2 material for lithium ion battery cathodes is successfully synthesized from a hollow hierarchical precursor that derives from hydrothermal method. The obtained material with unique 3D corn-like architecture is assembled from a mirco-rod body and numerous nanoparticles surface, which expand the electrochemical active area, depress the Ni/Li disorder, and alleviate the pulverization. As a proof of practical application, the cathode delivers a high-rate capacity of 186.94 mA h g −1 , and the capacity retention is 85.71% after 100 cycles at 200 mA g −1 . Particularly, this unique cathode architecture is stable, tolerates high-rate charging process, and keeps the original structure intact after fast Li + extraction and diffusion, thus possessing the advantages present in both nanostructures and microstructures. [ABSTRACT FROM AUTHOR]

Li 1.2 Mn 0.54 Ni x Co y O 2 (x+y=0.26, and x:y=1:1, 1:2, 2:1, 1:3, 3:1) was synthesized by aerogel with urea as chelating agent. The physical and electrochemical properties of the cathode materials were investigated through X-ray diffraction, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy analyses as well as and charge/discharge tests. Results showed that samples with different Ni/Co ratios crystallized well and showed a layered structure. The sample, Li 1.2 Mn 0.54 Ni 0.195 Co 0.065 O 2 (x:y=3:1), delivered a high discharge capacity of 313 mA h g −1 at 20 mA g −1 and exhibited excellent cycle performance after 50 cycles, with a capacity of 247 mA h g −1 at 100 mA g −1 . [ABSTRACT FROM AUTHOR]

Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 is synthesized with spherical mesocrystal, which is prepared by modified hydrothermal method with urea as precipitator. X-ray diffraction, scanning electron microscopy, thermogravimetry, energy-dispersive X-ray spectroscopy, transmission electron microscope, inductive coupled plasma-mass spectrometry, cyclic voltammetry, electrochemical impedance spectroscopy, and charge/discharge test are conducted to evaluate the physical and electrochemical properties of the spherical mesocrystal and resulting materials. Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 synthesized with spherical mesocrystal at 190 °C delivers a high discharge capacity of 339 mA h g −1 at 20 mA g −1 and maintains a discharge capacity of 201 mA h g −1 at 100 mA g −1 . Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 also exhibites excellent rate capability and cycle performance after 50 cycles, with a capacity of 150 mA h g −1 at 200 mA g −1 . All tests prove that the lithium-rich materials synthesized with spherical mesocrystal have excellent electrochemical properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] ZnWO4/CNTs composites have been prepared by sol–gel method as anode material of Li-ion battery. [•] CNTs addition improves the conduction and alleviates mechanical stress caused by the volume expansion of ZnWO4. [•] Composites showed the better electrochemical performance such as rate capability, specific capacitance, and cycle performance. [Copyright &y& Elsevier]

Abstract: Multi-walled carbon nanotubes (MWCNTs)-doped lithium vanadium phosphate Li3V2(PO4)3 (LVP)/MWCNTs x (x =0, 1, 3, 4, 5, 7wt.%) cathode materials for lithium ion batteries are synthesized by a microwave assisted sol–gel method. Moreover, the influences of doped MWCNTs on the physicochemical and electrochemical properties of the as-prepared samples are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical experiments. The results show that the optimal doping amount of MWCNTs is 4wt.%. Under this condition, the LVP/MWCNTs4wt.% sample has an monoclinic structure, the average particle size is about 0.2–4μm with very fine particle size, uniform shape and loose agglomeration. When charge/discharge at 0.1C, the sample reached the maximum discharge capacity (130mAhg−1), which is comparable to its theoretical capacity. Comparing with the sample obtained by conventional solid-state route, the obtained materials display lower charge transfer resistance, higher rate capability and excellent reversibility. The above experiments demonstrate that the LVP/MWCNTs4wt.% is a very promising cathode material which will be used in the future for lithium ion batteries. [Copyright &y& Elsevier]

Copper incorporated in Li 3 V 2 (PO 4 ) 3 /C cathode materials for high-rate Li-ion batteries were prepared by a self-catalysed sol-gel approach followed by a sintering process. The effect of copper incorporating amounts on the crystal structure, morphology and related electrochemical properties of Li 3 V 2 (PO 4 ) 3 /C was investigated. It is noteworthy that the impurity Li 3 PO 4 phase can be effectively affected by copper-incorporating without any significant influence on the surface morphology and crystal structure; moreover, the carbon layer coated onto Li 3 V 2 (PO 4 ) 3 -Cu 0.05 /C can be separated into the porous inner layer and the graphene-type outer layer. Benefiting from above two factors, copper-incorporated Li 3 V 2 (PO 4 ) 3 /C composite with improved electrochemical properties has been achieved. In comparison with pure Li 3 V 2 (PO 4 ) 3 /C, the Li 3 V 2 (PO 4 ) 3 -Cu 0.05 /C composite delivers a reversible specific capacity of 123.3 mAh g −1 after 50 cycles at a current rate of 1C and 116.2 mAh g −1 at 10C, maintaining 98.2% and 89.5% of capacity retention, respectively, and even cycled at 20C rate, it still possesses 105.4 mAh g −1 of discharge capacity, demonstrating an excellent rate capability and cycling stability. [ABSTRACT FROM AUTHOR]

A Bi 2 WO 6 /graphene composite synthesized by sol–gel and sintering processes was investigated as anode material for Li-ion batteries. The morphology and structure of the products were analyzed by SEM, TEM, and XRD. The electrochemical performance of Bi 2 WO 6 /graphene composite was investigated by the galvanostatic charge/discharge method, cyclic voltammetry and electrochemical impedance spectroscopy. Results showed that the first cycle of the reversible specific capacity of Bi 2 WO 6 /graphene composite reached 697.1 mA h g −1 at 50 mA g −1 . Charge/discharge cycling study indicated that the Bi 2 WO 6 /graphene composite had excellent cycling stability and superior rate capability. [ABSTRACT FROM AUTHOR]