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All-solid-state lithium–sulfur batteries are regarded as promising high safety- and high energy-density–energy-storage devices. However, the dissolution of lithium polysulfide intermediate species and the growth of dendrites on the lithium metal anode during cycling causes capacity fading and hidden security problems. Herein, we designed a composite solid polymer electrolyte based on poly(thioether)/polyethylene oxide (PTE/PEO) with a sizeable electrochemical window, enhanced ionic conductivity, and attractive mechanical properties. In the PTE composite electrolyte, the interactions of PTE with the –CF3 and SO2– groups of the (NSO2CF3)2− anion enhanced the dissociation of lithium salts to release more Li+ and improve the ionic conductivity. Also, traces of short-chain polysulfides could be observed on the cathode, demonstrating the successful conversion of the longer-chain polysulfides, leading to minimum parasitic reactions, preventing polysulfide dissolution, and inhibiting lithium dendrite. Benefiting from the improvements in electrolytes, high capacity and safety of lithium–sulfur batteries could be achieved. [ABSTRACT FROM AUTHOR]

Nb-modified anatase-supported Pt nanoparticles were synthesized for the efficient conversion of cellulose to light bioalcohols. Characterization confirmed the presence of SMSIs in the catalysts, offering adjacent hydrogenation sites, Brønsted and Lewis acid sites. Treating the catalysts in humid air enhanced the acidic concentration, accelerating the key step during the reaction. [ABSTRACT FROM AUTHOR]

We report the synthesis of a tantalum phosphate catalyst with abundant strong acid sites, which is very active for the catalytic conversion of acetone into mesitylene. Characterizations, kinetic studies, and theoretical results show a relationship between the acidic sites and catalytic performance in this reaction. [ABSTRACT FROM AUTHOR]

Here we prepare a hexagonal boron nitride (h-BN)–polyethylene oxide composite polymer electrolyte via a convenient casting method, which shows high mechanical strength. Meanwhile, the electrochemical properties (electrochemical window and lithium ion transference number) are enhanced but the ionic conductivity of the h-BN composite electrolyte is decreased after adding h-BN. Density functional theory (DFT) calculation results show that a stronger binding effect is observed between TFSI− and BN, compared to that between Li+ and BN. Molecular dynamics (MD) simulations are also utilized to study the mechanism behind the enhanced Li ion diffusion by h-BN addition. Li+ diffusion in PEO/LiTFSI/BN is lower than that in the PEO/LiTFSI system, but the diffusion of TFSI− exhibits a more significant decline rate in the presence of BN. This indicates that the presence of BN suppresses anion motion and enhances selectivity in Li+ transport. Thus, the PEO/LiTFSI/h-BN composite electrolyte exhibits higher Li ion conductivity but lower anion diffusivity than the PEO/LiTFSI system. Hence the h-BN composite polymer electrolyte in a Li/Li symmetric battery provides a long cycling time of 430 h at 0.2 mA cm−2. A Li metal/LiFePO4 full battery with the PEO/LiTFSI/h-BN composite electrolyte also works more efficiently for long-term cycling (140 cycles) than a filler-free PEO based electrolyte (39 cycles). [ABSTRACT FROM AUTHOR]

Transition metal vanadates have gained significant attention as high performance anode materials for lithium ion batteries (LIBs). Herein, we successfully fabricated a novel hierarchical hybrid nanostructure of ordered mesoporous carbon (CMK-3) supported Ni3V2O8 composites (Ni3V2O8@CMK-3) through a facile hydrothermal method and a post-calcination process for the first time. Within such a hierarchical hybrid structure, short intercrossed Ni3V2O8 nanorods are firmly anchored onto the external surface of CMK-3 and ultrafine Ni3V2O8 nanoparticles are embedded in the internal channels of CMK-3. Benefitting from their robust porous structure and excellent conductive characteristic, the as-prepared hierarchical hybrid Ni3V2O8@CMK-3 composites exhibit long-term cycle stability with a high reversible capacity of 945.9 mA h g−1 after 200 cycles at a current density of 500 mA g−1 and superior high-rate capability (161.5 mA h g−1 when cycled at 20 A g−1) when used as a promising anode for LIBs. [ABSTRACT FROM AUTHOR]

Carbonaceous hybrid nanocomposites with a porous flaky structure hold great promise as high-performance electrodes for lithium-ion batteries (LIBs); yet large-scale synthesis is still a challenge. In this work, we successfully develop a novel carbon hybrid structure of carbon-coated ZnFe2O4 nanoflakes (ZnFe2O4@C NFs) through a fast ethylene glycol (EG)-mediated metal alkoxide method, refluxing at 200 °C in EG and a post-calcination at 500 °C in a N2 atmosphere. The organic components in the pre-synthesized ZnFe-alkoxide precursor (ZnFe2(OCH2CH2O)4) can be transferred into an amorphous carbon layer easily surrounding the crystalline ZnFe2O4 subunits during the annealing process. The flaky morphologies of the as-prepared ZnFe2O4@C hybrids are highly dependent on the refluxing temperature. Upon increasing the refluxing temperature from 140 °C to 200 °C, the sphere-like morphology of the ZnFe2O4@C composites gradually evolves into microflowers and separate nanoflakes. When used as an anode for LIBs, the hybrid ZnFe2O4@C NFs present excellent electrochemical performance with high discharge capacity, long-term cyclic stability and superior high-rate capability. Even after 1000 cycles at 0.5 A g−1, the hybrid ZnFe2O4@C NFs still deliver a stable reversible discharge capacity of 778.6 mA h g−1. [ABSTRACT FROM AUTHOR]

Hybrid carbon-coated transition metal oxides (TMOs@C) offer enhanced lithium storage capabilities, but the facile formation of TMOs@C nanocomposites remains a great challenge. Herein, we report a novel hierarchical hybrid nanostructure of carbon-coated CoFe2O4 twin elliptical frustums (CoFe2O4@C TEFs) via a quick one-pot refluxing reaction in ethylene glycol (EG) followed by an annealing treatment. When evaluated as an anode in lithium-ion batteries (LIBs), the resultant CoFe2O4@C TEF hybrids demonstrate good electrochemical performance with high reversible specific capacity, excellent rate capability and super-long life cycle. After 600 cycles at a current density of 500 mA g−1, the resultant TEFs still deliver a stable reversible discharge capacity of 875 mA h g−1. This work demonstrates the extensive potential of such simple synthetic methods towards various carbon coated transition metal oxide composites for energy conversion and storage devices. [ABSTRACT FROM AUTHOR]

Hierarchical hybrid nanostructures based on flexible graphene sheets and ternary transition metal oxides have attracted special attention as high-performance electrode materials for next-generation lithium-ion batteries (LIBs) yet their practical application is often beset with challenges. In this work, we report a hierarchical hybrid nanocomposite of reduced graphene oxide supported mesoporous Co3V2O8 nanoparticles (rGO@Co3V2O8 NPs) through a simple hydrothermal synthesis and post-calcination. This unique hybrid architecture when used as an anode in LIBs would effectively facilitate charge transfer, maintain structural integrity and accommodate the volume variation of the electrode materials during the repeated charge/discharge processes. As a result, the hybrid rGO@Co3V2O8 NPs manifest a very stable high reversible capacity of 1050 mA h g−1 over 200 cycles at a current density of 50 mA g−1 and excellent rate capability. Importantly, even when cycled at a higher current density of 200 mA g−1, a stable reversible capacity of 899 mA h g−1 and a remarkable cycling stability could also be achieved after 600 cycles. These results indicate the potential suitability of such mesoporous nanoparticles on graphene nanostructures for high-rate and long cycle life anode materials. [ABSTRACT FROM AUTHOR]

Ultrathin CoMn2O4 nanosheets supported on reduced graphene oxide (rGO) are successfully synthesized through a simple co-precipitation method with a post-annealing treatment. With the assistance of citrate, the free-standing CoMn2O4 ultrathin nanosheets can form porous overlays on both sides of the rGO sheets. Such a novel hybrid nanostructure can effectively promote charge transport and accommodate volume variation upon prolonged charge/discharge cycling. When evaluated as a promising electrode for supercapacitors in a 6 M KOH solution electrolyte, the hybrid nanocomposites demonstrate highly enhanced capacitance and excellent cycling stability. [ABSTRACT FROM AUTHOR]

Hybrid nanosheet structures based on carbon coated metal oxides still attract promising interest as high-performance electrode materials for next-generation lithium-ion batteries (LIBs). In this study, we develop a simple one-pot solution method to synthesize large-scale flat Fe3O4 nanosheet hybrid structures coated with an amorphous carbon overlayer (denoted as Fe3O4@C NSs) followed by a thermal annealing treatment. It is found that the refluxing temperature plays an important role in adjusting the morphology of the Fe3O4@C hybrid. Increasing the temperature from 140 °C to 200 °C will lead to flower-like hybrid structures constructed by Fe3O4 nanoflakes gradually growing, rupturing, and finally evolving into flat and completely separate nanoflakes with large size at 200 °C. When evaluated as an anode material for LIBs, the hybrid Fe3O4@C NSs demonstrate a high reversible capacity of 1232 mA h g−1 over 120 cycles at a current density of 200 mA g−1, and remarkable rate capability. [ABSTRACT FROM AUTHOR]

Nb-modified anatase-supported Pt nanoparticles were synthesized for the efficient conversion of cellulose to light bioalcohols. Characterization confirmed the presence of SMSIs in the catalysts, offering adjacent hydrogenation sites, Brønsted and Lewis acid sites. Treating the catalysts in humid air enhanced the acidic concentration, accelerating the key step during the reaction.

Carbonaceous hybrid nanocomposites with a porous flaky structure hold great promise as high-performance electrodes for lithium-ion batteries (LIBs); yet large-scale synthesis is still a challenge. In this work, we successfully develop a novel carbon hybrid structure of carbon-coated ZnFe 2 O 4 nanoflakes (ZnFe 2 O 4 @C NFs) through a fast ethylene glycol (EG)-mediated metal alkoxide method, refluxing at 200 °C in EG and a post-calcination at 500 °C in a N 2 atmosphere. The organic components in the pre-synthesized ZnFe-alkoxide precursor (ZnFe 2 (OCH 2 CH 2 O) 4 ) can be transferred into an amorphous carbon layer easily surrounding the crystalline ZnFe 2 O 4 subunits during the annealing process. The flaky morphologies of the as-prepared ZnFe 2 O 4 @C hybrids are highly dependent on the refluxing temperature. Upon increasing the refluxing temperature from 140 °C to 200 °C, the sphere-like morphology of the ZnFe 2 O 4 @C composites gradually evolves into microflowers and separate nanoflakes. When used as an anode for LIBs, the hybrid ZnFe 2 O 4 @C NFs present excellent electrochemical performance with high discharge capacity, long-term cyclic stability and superior high-rate capability. Even after 1000 cycles at 0.5 A g -1 , the hybrid ZnFe 2 O 4 @C NFs still deliver a stable reversible discharge capacity of 778.6 mA h g -1 .

Ultrathin CoMn2O4 nanosheets supported on reduced graphene oxide (rGO) are successfully synthesized through a simple co-precipitation method with a post-annealing treatment. With the assistance of citrate, the free-standing CoMn2O4 ultrathin nanosheets can form porous overlays on both sides of the rGO sheets. Such a novel hybrid nanostructure can effectively promote charge transport and accommodate volume variation upon prolonged charge/discharge cycling. When evaluated as a promising electrode for supercapacitors in a 6 M KOH solution electrolyte, the hybrid nanocomposites demonstrate highly enhanced capacitance and excellent cycling stability.