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Sustainable and green manufacturing of hard carbon (HC) material in a low-cost way is the key issue in promoting its industrial applications in Na-ion batteries (SIB). Nowadays, most synthesis ways to prepare HC need the help of chemical reagents to improve its Na-ion storage performance. Herein, we firstly developed a completely green biological fermentation technology to prepare HCs on a large scale using cheap and renewable carbon sources of various biomass starch. Pre-treatment by bio-fermentation can effectively modify the carbon precursor for facile pyrolysis to fabricate starch-based HCs, and make its internal microstructure with larger interlayer spacing, more disordered structure and abundant closed micropores. Finally, a case of cornstarch-based hard carbon exhibits a high reversible capacity of 335 mA h g−1 at a current density of 30 mA h g−1 and high rate performance with a reversible capacity of 140.6 mA h g−1 even at a high current of 5 A g−1 as well as long cycling stability. In-situ Raman spectra, ex-situ SAXS and ex-situ XPS tests during discharge and charge process reveal the pore filling mechanism of quasi-metallic Na in hard carbon anode. Such a "bread-making"strategy is a facile and scalable route to fabricate various starch-based hard carbons with improved performance, demonstrating a very practically promising application for industrial manufacture. • A green biological fermentation technology to prepare HCs is firstly developed. • Renewable carbon sources of various biomass starch derived HCs are achieved. • Bio-fermentation effectively improve interlayer spacing with abundant closed micropores. • HC with a reversible capacity of 335 mA h g−1 and long cycling stability is demonstrated. • Such a "bread-making" strategy is a scalable route to fabricate hard carbons at a kilogram. [ABSTRACT FROM AUTHOR]

Abstract: A series of La–M–Cu–Zn–O (M = Y, Ce, Mg, Zr) based perovskite-type catalysts are prepared by sol–gel method and characterized by XRD, BET, TPR, N2O-adsorption, XPS and TPD techniques. The results indicate that all the catalysts exhibit La2CuO4 perovskite structure. The addition of Ce, Mg and Zr lead to smaller particles, lower reduction temperature, higher Cu dispersion, larger amount of hydrogen desorption at low temperature and more amount of basic sites. However, Y has less affects on the physicochemical properties. The catalysts derived from perovskite-type precursors show high selectivity for methanol, which is correlated with the Cuα+ species that exists in the reduced catalysts. More exposed Cu surface area is favorable for high CO2 conversion. [Copyright &y& Elsevier]

Abstract: In this paper, monodispersed LiFePO4 nanopillows have been successfully synthesized via solvothermal route with ethylene glycol (EG) as reaction medium. Subsequently, with the basis of the solvothermally synthesized monodispersed LiFePO4 nanopillows, monodispersed LiFePO4@C core–shell nanostructures are facilely prepared in high yield. Based on the experimental results, the formation mechanism of the monodispersed LiFePO4 nanopillows has been discussed simply. The monodispersed LiFePO4@C core–shell nanostructures exhibit nice capacity retention and high rate capacity due to the full carbon-coating and the well-crystallized nanosized particles. [Copyright &y& Elsevier]

Tin (Sn)-based materials are potential alternatives to the commercial graphite anode for next-generation Li-ion batteries (LIBs) due to their high theoretical capacity. However, the poor cyclic stability, originating from the large volumetric changes during charge/discharge process, hinder their practical utilization. Herein, we have successfully prepared a Sn-based metal-organic framework (MOF, Sn-PMA), and explored as potential anode materials in LIBs. Benefiting from its layered structure and efficient electron transport channels, Sn-PMA electrodes deliver a high initial capacity of 1567 mAh g−1, at 100 mA g−1, and maintained a reversible capacity of 707 mAh g−1, at 800 mA g−1, after 400 cycles. Furthermore, the detailed post-electrochemical structural, morphological and compositional analysis is carried out to unveil the structural changes and Li-ion storage mechanism of electrodes. Ex-situ XRD and XPS results revealed that, in Sn-PMA electrode, O atom, coordinated to the Sn atom, exhibited higher electronegativity, served as major Li-ion storage site and rendered excellent cyclic stability due to a stable structure. Kinetic analyses reveal that the excellent performance of the Sn-PMA is typical attributed to the pseudocapacitive contribution induced by the special porous structure. A Sn-based MOF has successfully prepared by hydrothermal reaction, which shows outstanding lithium storage properties. Image 1 • Sn-based MOF was fabricated through a simple hydrothermal reaction. • Sn-PMA exhibits excellent electrochemical performance with typical pseudocapacitive contribution. • Ex-situ XRD and XPS reveal the lithium storage mechanism of Sn-PMA. [ABSTRACT FROM AUTHOR]

Abstract: We report a simple strategy to prepare a hybrid of lithium titanate (Li4Ti5O12, LTO) nanoparticles well-dispersed on electrical conductive graphene nanosheets as an anode material for high rate lithium ion batteries. Lithium ion transport is facilitated by making pure phase Li4Ti5O12 particles in a nanosize to shorten the ion transport path. Electron transport is improved by forming a conductive graphene network throughout the insulating Li4Ti5O12 nanoparticles. The charge transfer resistance at the particle/electrolyte interface is reduced from 53.9Ω to 36.2Ω and the peak currents measured by a cyclic voltammogram are increased at each scan rate. The difference between charge and discharge plateau potentials becomes much smaller at all discharge rates because of lowered polarization. With 5wt.% graphene, the hybrid materials deliver a specific capacity of 122mAhg−1 even at a very high charge/discharge rate of 30C and exhibit an excellent cycling performance, with the first discharge capacity of 132.2mAhg−1 and less than 6% discharge capacity loss over 300 cycles at 20C. The outstanding electrochemical performance and acceptable initial columbic efficiency of the nano-Li4Ti5O12/graphene hybrid with 5wt.% graphene make it a promising anode material for high rate lithium ion batteries. [Copyright &y& Elsevier]

Abstract: One of the most attractive research areas in lithium-ion batteries (LIBs) is to design elaborate nanostructure of the electrode, which has been considered as keys to solve the problems such as the low energy density, slow lithium ion and electron transport, and the large volume change of electrode materials during cycling processes. Here, mesoporous Co3O4 with controllable structures was directly grown on a graphene membrane by hydrothermal reaction followed by annealing treatment, and used as an integrated anode in LIBs without using metallic current collector, binder and conductive additive. The light graphene membrane as current collector with high electrical conductivity and stability contributes to the high energy density of LIBs. A mesoporous structure with enough space is beneficial to lithium ion diffusion and strain buffer of Co3O4 during discharge/charge processes, rendering the electrodes high performance. The integrated electrode shows good rate capability and impressive cycling stability without capacity loss over 500 cycles under a high current density of 500 mA g−1. [Copyright &y& Elsevier]

Abstract: Nanocomposites of Mn3O4 nanoparticles and graphene (GR) nanosheets – Mn3O4@GR can be made by growing Mn3O4 nanoparticles directly on the surfaces of GR in solvothermal reactions. The asymmetric supercapacitors constructed with Mn3O4@GR as positive and activated carbon (AC) as negative electrodes, respectively, show highly enhanced performances in energy storage. It was found that the electrolytes employed in constructing electrodes of the devices can influence the performances of Mn3O4@GR supercapacitors dramatically. Compared to their energy density in KOH electrolyte, the devices exhibit improved charge storage performances in Na2SO4 electrolyte. Furthermore, the charge storage abilities of the devices are closely related to the amount of Mn3O4 nanoparticles loaded onto the surface of GR nanosheets. The performances of Mn3O4@GR//AC asymmetric supercapacitors can be optimized by carefully tailoring the composition of electrode materials and adjusting the electrolytes for making the devices. [Copyright &y& Elsevier]

Inspired by the successful application of spinel LiMn 2 O 4 cathode in Li-ion batteries, analogous spinel ZnMn 2 O 4 (ZMO) is regarded as a promising cathode for rechargeable aqueous Zn-ion batteries (ZIBs). Nevertheless, clear Zn2+ storage mechanism and phase transition of spinel ZMO is still scarce. Herein, in the first time, we report an in-situ Raman study in dynamically probing the phase and structure evolution of a spinel ZMO-based cathode during charging-discharging process, in which spinel ZMO nanoparticles are anchored on porous carbon polyhedrons (PCPs). By in-situ investigation, it is demonstrated that the electrochemical mechanism can be attributed to the highly reversible phase transformation between spinel ZMO and λ-type MnO 2 upon Zn2+ insertion/extraction, which is driven by stepwise oxidation and reduction reactions of Mn3+/Mn4+ along with efficient charge carriers. Furthermore, the resultant ZMO@PCPs composite as cathode delivers a large reversible capacity of 125.6 mAh g−1 at a high current density of 1 A g−1 after 2000 cycles, representing superior long-term cyclic stability (capacity retention of 90.3%) and remarkable rate capability in aqueous ZIBs. As a proof of concept, high-performance flexible aqueous ZIBs are fabricated and represent stable electrochemical performance under various deformation states, indicating their potential applications in portable and wearable electronics. • A 3D-confined spinel ZnMn 2 O 4 cathode is proposed for aqueous Zn-ion batteries (ZIBs). • Zn2+ storage mechanism is explored by in-situ Raman investigation in the first time. • Reversible phase change between ZnMn 2 O 4 and λ-MnO 2 upon Zn2+ insertion/extraction. • The resultant cathode represents superior electrochemical behaviors in aqueous ZIBs. • Flexible aqueous ZIBs show stable electrochemical performance at deformation states. [ABSTRACT FROM AUTHOR]