Metallic vanadium trioxide intercalated with phase transformation for advanced aqueous zinc-ion batteries

Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan has affected their development.Herein,we report a metallic vanadium trioxide material intercalated with phase transformation as cathode applied in aqueous zinc-ion batteries.It offers satisfactory electrochemical performances with a high specific capacity(435 mAh g^(-1) at 0.5 A g^(-1)),decent power density(5.23 kW kg^(-1))and desired energy density(331 Wh kg^(-1)),as well as good cyclability.The superior performance originates from the stable structure and fast Zn^(2+)diffusion,enabled by the pre-intercalation of Zn^(2+)and water molecules.

Controllable assembling of highly-doped linked carbon bubbles on graphene microfolds

Carbon-based microassemblies(CMs) have attracted significant attention in numerous applications due to their unique hierarchical structures and delicate building blocks,especially when hollow carbon spheres(HCSs) are reasonably introduced into the construction.Herein,a new design for novel HCSscombined CMs is proposed.Remarkably,the HCSs are linear carbon bubbles linked one-by-one, arranging into necklaces decorating on the graphene microfolds.Detailed thermal analysis confirm that high temperatures straighten the linked carbon bubbles into bamboo-like carbon nanofibers,evidently due to the attenuation of doping degree.Benefiting from the abundant active sites of carbon bubbles,the obtained CMs exhibit satisfactory electrocatalytic activity for oxygen reduction reactions.This work establishes a bridge to precisely control the synthesis of carbon-based hierarchical architectures.

Designing heterostructured FeP–CoP for oxygen evolution reaction:Interface engineering to enhance electrocatalytic performance

It is significant to develop highly efficient electrocatalysts for energy conversion systems.Interface engineering is one of the most feasible approaches to effectively enhance the electrocatalytic activity.Herein,the density functional theory(DFT)calculations predict that the potential barriers of Fe sites at the interface of FeP–CoP heterostructures are lower than that of Fe sites in FeP nanoparticles(NPs),Co sites in CoP NPs,or Co sites in heterostructures.Motivated by the DFT calculation results,FeP–CoP heterostructures have been designed and synthesized by a metal–organic frameworks(MOFs)confined-phosphorization method.The FeP–CoP exhibits the lowest overpotential of 230 mV at the current density of 10 mA·cm^(−2)for oxygen evolution reaction(OER),compared with FeP(470 mV)and CoP(340 mV),which outperforms most of transition metal-based catalysts.The Tafel analysis of FeP–CoP heterostructures shows an improved reaction kinetic pathway with the smallest slope of 90.3 mV·dec^(−1),as compared to the Tafel slopes of FeP NPs(137 mV·dec^(−1))and CoP NPs(114 mV·dec^(−1)).And the FeP–CoP shows extraordinary long-term stability over 24 h.The excellent activity and long-term stability of FeP–CoP derive from the synergistic effect between FeP and CoP.

Stereoassembled V_(2)O_(5)@FeOOH Hollow Architectures with Lithiation Volumetric Strain Self-Reconstruction for Lithium-Ion Storage

Vanadium oxides have recently attracted widespread attention due to their unique advantages and have demonstrated promising chemical and physical properties for energy storage.This work develops a mild and efficient method to stereoassemble hollow V_(2)O_(5)@FeOOH heterostructured nanoflowers with thin nanosheets.These dual-phased architectures possess multiple lithiation voltage plateau and well-defined heterointerfaces facilitating efficient charge transfer,mass diffusion,and self-reconstruction with volumetric strain.As a proof of concept,the resulting V_(2)O_(5)@FeOOH hollow nanoflowers as an anode material for lithiumion batteries(LIBs)realize high-specific capacities,long lifespans,and superior rate capabilities,e.g.,maintaining a specific capacity as high as 985 mAhg^(-1) at 200mAg^(-1) with good cyclability.