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Graphical abstract Highlights • A 3D network GPE composed of PVDF-HFP and PETT-Ester is successfully fabricated. • The GPE exhibits a wide electrochemical window of 5.05 V (vs. Li/Li+). • The GPE effectively suppresses the extension of lithium dendrite. • The Li/GPE/S cell shows a high specific capacity retention. Abstract A UV-light polymerized three-dimensional (3D) network gel polymer electrolyte (GPE) is designed and fabricated for solid-state lithium-sulfur (Li-S) batteries. The GPE exhibits wide electrochemical window up to 5.05 V (vs. Li+/Li), outstanding thermostability and mechanical property. Besides, the GPE effectively suppresses the extension of lithium dendrite and the electron-donating groups in GPE inhibit the shuttle of lithium polysulfides. The assembled solid-state Li-S batteries with the 3D network GPE show high specific capacity retention of 69.1% after 300 cycles at 0.5 C. With the consideration of these, the GPE in this report undoubtedly provides an effective technique to design high performance solid-state Li-S batteries. [ABSTRACT FROM AUTHOR]

High-quality solid electrolyte is essential for the growing need of lithium ion batteries. Herein, we report a novel organic-inorganic composite electrolyte based on Li 7 La 3 Zr 2 O 12 ceramic powder incorporated into PVDF-HFP through a simple combined method. At room temperature, the composite polymer electrolyte (CPE) possesses a good ionic transmission improvement of 3.71 × 10 −4  S cm −1 . The CPE behaves a fine lithium ion transference number of 0.58 and an electrochemical window of up to 4.65 V. CPEs display meliorative electrochemical stability compared to pure PVDF-HFP electrolyte. The cathode presents an excellent initial discharge capacity of 163.1 mAh g −1 at 0.2 C in Li/CPE/LiFePO 4 cell. The cell with CPE displays much better capacity retention than that with pure PVDF-HFP electrolyte. The Li 7 La 3 Zr 2 O 12 modified PVDF-HFP is a promising electrolyte for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Integral construction of lithium sulfide (Li 2 S) cathode is indispensable and vital for developing high-performance lithium-sulfur (Li-S) batteries. Herein we have demonstrated a facile strategy for fabricating free-standing carbon paper supported Li 2 S@C (P-Li 2 S@C) integrated cathode. The P-Li 2 S@C cathode is synthesized through simple pyrolysis of low-cost lithium sulfate (Li 2 SO 4 ) and chitosan, and embedded in the double carbon matrixes with carbon paper support and outer CVD-carbon layer. Li 2 S nanoparticles are homogeneously dispersed in the above designed double carbon matrixes. The P-Li 2 S@C cathode exhibits an initial discharge capacity of 820 mAh g −1 at 0.1 C and still maintains 430 mAh g −1 after 100 cycles, superior to the P-Li 2 S counterpart (480 mAh g −1 at 0.1 C and 150 mAh g −1 after 100 cycles). Our research verifies the effectiveness of double carbon modification on the Li 2 S, especially, the outer carbon coating not only improves the electrical conductivity of electrode, but also further prohibits the “shuttle effect” of polysulfides. [ABSTRACT FROM AUTHOR]

Surface conductive engineering on Li 2 S is critical for construction of advanced cathodes of lithium-sulfur batteries. Herein, we construct a high-performance Li 2 S-based composite cathode with the help of three-dimensional reduced graphene oxide (3D-rGO) network and outer carbon coating. Typically, the Li 2 S@C particles are uniformly embedded into 3D-rGO to form a binder-free 3D-rGO-Li 2 S@C cathode by the combination of a liquid solution-evaporation coating and PVP (Polyvinyl Pyrrolidone) carbonization. The 3D-rGO-Li 2 S@C cathode exhibits a high initial discharge capacity of 856 mAh g −1 at 0.1C, superior cycling stability with a capacity of 388.4 mAh g −1 after 200 cycles at 1C, corresponding to a low capacity fading rate. It is demonstrated that the outer conductive coating is effective and necessary for electrochemical enhancement of Li 2 S cathodes by improving electrical conductivity and prohibiting polysulfide from shuttling during cycling. [ABSTRACT FROM AUTHOR]

A novel 2Li 3 V 2 (PO 4 ) 3 ·LiV 3 O 8 composite with short rod and thin plate shapes is synthesized through sol–gel method followed by hydrothermal and solid–state reaction. LiV 3 O 8 is used as an additive to improve the capacity of Li 3 V 2 (PO 4 ) 3 . In the composite cathode, active impurity phase Li 0.3 V 2 O 5 is also present, which has little impact on the whole electrochemical properties. The 2Li 3 V 2 (PO 4 ) 3 ·LiV 3 O 8 composite delivers a high initial capacity of 162.8 mAh g −1 at a current density of 100 mA g −1 in the voltage range of 2.0–4.3 V. Furthermore, the composite with high crystallinity also shows high electrochemical reversibility and good rate capability. The diffusion coefficient of Li ions in the composite is in the range of 10 −11 –10 −9 cm 2 s −1 obtained from galvanostatic intermittent titration technique. [ABSTRACT FROM AUTHOR]

A novel 0.6Li 3 V 2 (PO 4 ) 3 ·0.4Li–V–O composite cathode material is synthesized by sol-gel method followed by solvothermal and solid state reaction. The morphology and structure of the composite are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photo-electron spectroscopy (XPS). The composite particles are well-crystallized and present uniform nanoplate alike. Except Li 3 V 2 (PO 4 ) 3 phase, LiV 2 O 5 and VO 2 are also present in the composite. The 0.6Li 3 V 2 (PO 4 ) 3 ·0.4Li–V–O electrode delivers a discharge capacity of 149.3 mAh g −1 at 50 mAg −1 between 2.0 V and 4.3 V, and has higher rate property than Li 3 V 2 (PO 4 ) 3 . The diffusion coefficients of Li ions in the composite are in the range of 10 −9.5 − 10 −7.5 cm 2 s −1 obtained from galvanostatic intermittent titration technique (GITT). [ABSTRACT FROM AUTHOR]

Abstract: Novel Li1.2Mn0.5Co0.25Ni0.05O2 microcube is prepared through a simple binary template method. After calcined at 800 °C, lithium and nickel are permeated into the cathode material and a well-crystallized Li-rich layered oxide is obtained. Furthermore, hollow circle cube architecture is formed due to the decomposing of the carbonate. As a cathode material for lithium ion batteries (LIBs), the oxide with such architecture can deliver high initial discharge capacity of 272.9 mAh g−1 at a current density of 20 mA g−1. High reversible discharge capacities of 208 mAh g−1 and 110 mAh g−1 are obtained at a current density of 200 mA g−1 and 2000 mA g−1, respectively. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are performed to further study the hollow Li1.2Mn0.5Co0.25Ni0.05O2 microcube. It is remarkable that such architecture makes the Li-rich layered oxide Li1.2Mn0.5Co0.25Ni0.05O2 a promising cathode material for LIBs. [Copyright &y& Elsevier]

Highlights: [•] Cookies-shaped LiV3O8 material was synthesized by a facile sol–gel method. [•] The compound shows high capacity retentions at different current densities. [•] The good performance is due to high crystallinity and little dissolution of vanadium. [ABSTRACT FROM AUTHOR]

Abstract: LiVO3 materials are synthesized by combustion method with oxalic acid as fuel. Owing to its relatively low crystallization and small particle size, the LiVO3 calcined at 450 °C for 2 h displays optimal electrochemical performances, delivering a high discharge capacity of 298.4 mAh g−1 and 262.5 mAh g−1 between 1.0 and 3.5 V at a current density of 50 mA g−1 and 500 mA g−1 respectively, and exhibiting good cyclic stability. In this work, the chemical diffusion coefficient of Li+ (D Li+) in the LiVO3 electrode is determined by electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT). The value calculated by EIS is in the range of 10−9–10−8 cm2 s−1, while it calculated by GITT is 10−9.5–10−8 cm2 s−1. [Copyright &y& Elsevier]

Abstract: Cube-like and plate-like Li[Li0.2Mn0.54Ni0.13Co0.13]O2 particles are obtained after treated in LiCl and KCl molten salts at 800 °C, respectively, comparing to the ball-like original particles calcined in air. The oxide treated in KCl molten salt with large specific area of 17.05 m2 g−1 delivers high discharge capacities of 254.1 mAh g−1 and 168.5 mAh g−1 at current densities of 200 mA g−1 and 2000 mA g−1, respectively. In addition, enhanced cycle stability with capacity retention of 94.9% after 80 cycles at charge–discharge current densities of 200 mA g−1 is obtained for the oxide treated in LiCl molten salt with sacrifice of a little capacity. Such electrochemical performance change is proved to be independent of Li+ diffusion coefficient. It appears that the treatment in molten salts can effectively reform the electrochemical performances of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode materials for various applications. [Copyright &y& Elsevier]

Highlights: [•] Different metal sources are used to prepare Li[Li0.2Mn0.56Ni0.16Co0.08]O2 by sol–gel. [•] Porosity with surface area of 10.09m2 g−1 is only observed when nitrate is used. [•] High discharge capacity of 247.8mAhg−1 is obtained at 1°C for the porous oxides. [•] Porous morphology with good particle contact can efficiently reduce the impedance. [ABSTRACT FROM AUTHOR]

Abstract: LiVO3 is synthesized via a ball-milling route followed by a solid-state reaction at different temperatures. As cathode materials for lithium ion batteries, the electrochemical performances of LiVO3 are investigated by galvanostatic charge–discharge test and electrochemical impedance spectroscopy (EIS). The LiVO3 compound synthesized at 350 °C possesses the optimal performance, delivering an initial discharge capacity of 302.5 mAh g−1 between 1.0 V and 3.5 V at a current density of 50 mA g−1, and exhibiting a good cycling stability. Li-ion diffusion coefficient of 10−9.5–10−8 cm2 s−1 in the LiVO3 electrode is calculated by galvanostatic intermittent titration technique (GITT). The good performances can be attributed to its relatively low crystallization and small particle size. [Copyright &y& Elsevier]

Abstract: Hierarchical plate-arrayed LiV3O8 is synthesized by freeze drying method with polyacrylamide (PAM) as surfactant followed by calcination at 500 °C. As a cathode material for lithium-ion batteries, the plate-arrayed LiV3O8 delivers an initial discharge capacity of 255.2 mAh g−1 between 2.0 and 4.0 V at the current density of 50 mA g−1, and possesses a capacity retention of 88.7% after 60 cycles. Moreover, high discharge capacities of 145.2, 133.7 and 111.8 mAh g−1 can still be obtained after the 200th cycle at current densities of 600, 1500 and 3000 mA g−1, respectively. Electrochemical impedance spectroscopy (EIS) test indicates that the LiV3O8 electrode always has very low impedance during the 3rd to 180th cycles. The improved electrochemical performance is attributed to the high crystallinity and uniform arrayed structure of LiV3O8, which can facilitate the fast electron transport and Li ion diffusion in the electrode. [Copyright &y& Elsevier]

Abstract: Li-rich layered oxide Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is synthesized by combustion reaction using alcohol as both solvent and fuel. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the oxide synthesized at 800 °C exhibits perfect crystallinity and lattice ordering, and has particle sizes of 50–150 nm. The layered oxide delivers an initial discharge capacity of 290.1 mAh g−1 at a current density of 20 mA g−1 after activation, and exhibits improved rate capability with high discharge capacities of 238.6 and 165.0 mAh g−1 at current densities of 200 and 2000 mA g−1 in the voltage range of 2.0–4.8 V, respectively. Low Li-ion diffusion coefficient of 1.07 × 10−14−1.01 × 10−16 cm2 s−1 is calculated by galvanostatic intermittent titration technique (GITT) during the initial discharge process, indicating that the improved rate capability is mainly attributed to the small particle sizes of the Li-rich oxide. [Copyright &y& Elsevier]

Abstract: Li3V2(PO4)3/C cathode material was synthesized by using a freeze-drying method followed by carbon-thermal reduction. This as-prepared material has a uniform particle size distribution and a well carbon coating on the surface of Li3V2(PO4)3 particles. The Li3V2(PO4)3/C exhibits good electrochemical performance and cycling stability. Between 3.0 and 4.3V, the composite delivered a reversible capacity of 125.2mAhg−1 at a charge–discharge rate of 1.48C (1C=133mAg−1) and without obviously capacity fading after 100 cycles. Even at 14.8C and 29.6C rates, it can still deliver discharge capacities of 105.6mAhg−1 and 93.3mAhg−1, and the discharge capacities of 84.5 and 60.5mAhg−1 are sustained after 500 cycles, respectively. [Copyright &y& Elsevier]

Abstract: Ball-like LiMn0.4Ni0.4Co0.2O2 particles composed of flakes were synthesized by a simplified co-precipitation method followed by a solid-state reaction at temperatures of 600–900°C. The relationship between the flake thickness and the electrochemical performance of the layered oxides was investigated in this work. The layered oxide with a flake thickness of 80–100nm synthesized at 800°C has the best electrochemical performance among these cathode materials, especially the rate capability. An initial discharge capacity of 160mAhg−1 was obtained at 5C (1400mAg−1) in the voltage range of 2.5–4.5V, and the capacity retention was 80% after 50 cycles. The excellent rate capability is attributed to the well formed structure, short diffusion distance and good crystallinity. In addition, a detailed study of diffusion coefficient of Li+ was carried out to further understand this material. The value of calculated is in the range of 10−11 to 10−12 cm2 s−1. [Copyright &y& Elsevier]

Abstract: Carbon-coated layered oxide Li1.048Mn0.381Ni0.286Co0.286O2 is prepared by combining a co-precipitation and a direct current magnetron sputtering. TEM images show that the carbon layer is relatively well coated on the surface of oxide particles. The Li1.048Mn0.381Ni0.286Co0.286O2/C composite delivers an initial discharge capacity of 203.2mAhg−1 between 2.5 and 4.5V at 0.1C, and 94% of the initial discharge capacity can be retained after 100 cycles. Moreover, the carbon-coated oxide exhibits noticeable high-rate capacity of 145mAhg−1 at 5C, much higher than the pristine one (103mAhg−1 at 5C). The improved discharge capacity and cycle performance are attributed to the carbon coating, which protects the Li-rich cathode material from reacting with the electrolyte and retarding the incrassation of SEI film on the surface of oxide particles. [Copyright &y& Elsevier]

Abstract: Rod-like LiV3O8 composites have been fabricated by using a carbamide-assisted rheological phase reaction method. The electrochemical performances of the LiV3O8 materials prepared under different conditions are investigated by cyclic voltammograms, galvanostatic charge–discharge tests and electrochemical impedance spectroscopy (EIS). The rod-like LiV3O8 calcined at 500°C has the optimal performance, delivering an initial discharge capacity of 273.6 and 250.4mAhg−1 between 2.0V and 4.0V at a current density of 50 and 120mAg−1, respectively. After 60 cycles by applying 50mAg−1, a discharge capacity of 213.0mAhg−1 is obtained, showing a good cycling performance. The EIS studies show that the 500°C-LiV3O8 electrode has very low impedance increase during 1st to 240th discharge-charge cycles. All these results indicate that the rod-like LiV3O8 compound has a promising application as the cathode material for rechargeable lithium batteries. [Copyright &y& Elsevier]

Abstract: Plate-like Li3V2(PO4)3/C composite is synthesized via a solution route followed by solid-state reaction. The Li3V2(PO4)3/C plates are 40–100nm in thicknesses and 2–10μm in lengths. TEM images show that a uniform carbon layer with a thickness of 5.3nm presents on the surfaces of Li3V2(PO4)3 plates. The apparent Li-ion diffusion coefficient of the plate-like Li3V2(PO4)3/C is calculated to be 2.7×10−8 cm2 s−1. At a charge–discharge rate of 3C, the plate-like Li3V2(PO4)3/C exhibits an initial discharge capacity of 125.2 and 133.1mAhg−1 in the voltage ranges of 3.0–4.3 and 3.0–4.8V, respectively. After 500 cycles, the electrodes still can deliver a discharge capacity of 111.8 and 97.8mAhg−1 correspondingly, showing a good cycling stability. [Copyright &y& Elsevier]

Abstract: A nanosized LiFePO4/C composite with a complete and thin carbon-shell is synthesized via a ball-milling route followed by solid-state reaction using poly(vinvl alcohol) as carbon source. The LiFePO4/C nanocomposite delivers discharge capacities of 159, 141, 124 and 112mAhg−1 at 1C, 5C, 15C and 20C, respectively. Even at a charge–discharge rate of 30C, there is still a high discharge capacity of 107mAhg−1 and almost no capacity fading after 1000 cycles. Based on the analysis of cyclic voltammograms, the apparent diffusion coefficients of Li ions in the composite are in the region of 2.42×10−11 cm2 s−1 and 2.80×10−11 cm2 s−1. Electrochemical impedance spectroscopy and galvanostatic intermittent titration technique are also used to calculate the diffusion coefficients of Li ions in the LiFePO4/C electrode, they are in the range of 10−11–10−14 cm2 s−1. In addition, at −20°C, it can still deliver a discharge capacity of 122mAhg−1, 90mAhg−1 and 80mAhg−1 at the charge–discharge rates of 0.1C, 0.5C and 1C, respectively. [Copyright &y& Elsevier]