Aqueous Zinc-ion batteries (ZIBs), using zinc negative electrode and aqueous electrolyte, have attracted great attention in energy storage field due to the reliable safety and low-cost. A composite material comprised of VO2·0.2H2O nanocuboids anchored on graphene sheets (VOG) is synthesized through a facile and efficient microwave-assisted solvothermal strategy and is used as aqueous ZIBs cathode material. Owing to the synergistic effects between the high conductivity of graphene sheets and the desirable structural features of VO2·0.2H2O nanocuboids, the VOG electrode has excellent electronic and ionic transport ability, resulting in superior Zn ions storage performance. The Zn/VOG system delivers ultrahigh specific capacity of 423 mAh·g-1 at 0.25 A·g-1 and exhibits good cycling stability of up to 1,000 cycles at 8 A·g-1 with 87% capacity retention. Systematical structural and elemental characterizations confirm that the interlayer space of VO2·0.2H2O nanocuboids can adapt to the reversible Zn ions insertion/extraction. The as-prepared VOG composite is a promising cathode material with remarkable electrochemical performance for low-cost and safe aqueous rechargeable ZIBs.
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Novel hierarchical coral-like Ni-Mo sulfides on Ti mesh (denoted as HC-NiMoS/Ti) were synthesized through facile hydrothermal and subsequent sulfuration processes without any template. These non-precious HC-NiMoS/Ti hybrids were explored as bifunctional catalysts for urea-based overall water splitting, including the anodic urea oxygen evolution reaction (UOR) and cathodic hydrogen evolution reaction (HER). Due to the highly exposed active sites, excellent charge transfer ability, and good synergistic effects from multi-component reactions, the HC-NiMoS/Ti hybrid exhibited superior activity and high stability, and only a cell voltage of 1.59 V was required to deliver 10 mA·cm–2 current density in an electrolyte of 1.0 M KOH with 0.5 M urea.
The issues of hydrogen generation and storage have hindered the widespread use and commercialization of hydrogen fuel cell vehicles. It is thus highly attractive, but the design and development of highly active non-noble-metal catalysts for on-demand hydrogen release from alkaline NaBH4 solution under mild conditions remains a key challenge. Herein, we describe the use of CoP nanowire array integrated on a Ti mesh (CoP NA/Ti) as a three-dimensional (3D) monolithic catalyst for efficient hydrolytic dehydrogenation of NaBH4 in basic solutions. The CoP NA/Ti works as an on/off switch for on-demand hydrogen generation at a rate of 6,500 mL/(min·g) and a low activation energy of 41 kJ/mol. It is highly robust for repeated usage after recycling, without sacrificing catalytic performance. Remarkably, this catalyst also performs efficiently for the hydrolysis of NH3BH3.