Na2V6O16·2.14H2O nanobelts as a stable cathode for aqueous zinc-ion batteries with long-term cycling performance

Aqueous zinc-ion batteries(ZIBs) have been considered as one of the most promising electrochemical devices for large-scale energy storage system owing to their low cost and high safety. Herein, Na2V6O16·2.14H2O nanobelts are synthesized and applied as cathode material for ZIBs. The sample displays a high capacity of 466 m Ahg^-1 at 100 mAg^-1 and stable cycling performance with a capacity retention of 90% over 20 0 0 cycles at the 20 Ag^-1. Moreover, Na2V6O16·2.14H2O presents a capable rate ability and a high energy density of 312 Wh kg^-1 at a specific power of 70 Wkg^-1. The superior electrochemical performance is attributed to the large interlayer spacing and outstanding structure stability, which promise the highly reversible intercalation and extraction of zinc ion. The electrochemical kinetics and zinc ion storage mechanism are also investigated. This work demonstrates that nanoscale electrode materials with large interlayer spacing can effectively enhance the electrochemical performance of aqueous ZIBs, which can be extended to other metal ion batteries, such as magnesium ion batteries and aluminum ion batteries.

High-performance Na1.25V3O8 nanosheets for aqueous zinc-ion battery by electrochemical induced de-sodium at high voltage

Aqueous rechargeable zinc-ion batteries(ARZIBs) are expected to replace organic electrolyte batteries owing to its low price,safe and environmentally friendly characteristics.Herein,we fabricated vanadium-based Na1.25V3O8 nanosheets as a cathode material for ARZIBs,which present a high performance by electrochemical de-sodium at high voltage to form Na2V6O16 phase in the first cycle:high capacity of 390 mAh/g at 0.1 A/g,high rate perfo rmance(162 mAh/g at 10 A/g) and superior cycle stability(179 mAh/g with a high capacity retention of 88.2% of the maximum capacity after 2000 cycles).In addition,the cell exhibits a high energy density of 416.9 Wh/kg at 143.6 W/kg,suggesting great potential of the as-prepared Na1.25V3O8 nanosheets for ARZIBs.

Improvement on compressive properties of lotus-type porous copper by a nickel coating on pore walls

The aim of this work is to understand the effect of a thin coating on the compressive properties of the porous metal.In our work,the uniaxial compressive behavior and the energy absorption properties of the lotus-type porous copper deposited with Ni coatings with thickness from 3.9 to 4.8μm on pore walls were investigated.It is found that the Ni coating on pore walls shows a clear enhancement effect on compressive properties of the lotus-type porous copper,in which the specific yield strength and the energy absorption per unit mass at densification strain increase from 5.27 to 7.31 MPa cm3 g-1 and from 11.50 to 18.21 J g-1 with the Ni coating,respectively.Furthermore,the enhancement appears to be insensitive to the coating thickness.It is considered that the resistance of the interface between the nickel coating and the pore walls to the dislocation slip plays an important role in the improvement on compressive properties of the lotus-type porous copper.

High-performance (NH_(4))_(2)V_(6)O_(16).0.9H_(2)O nanobelts modified with reduced graphene oxide for aqueous zinc ion batteries

Ammonium vanadate has been considered as a competitive high-performance cathode material for aqueous Zn-ion batteries.However,it still suffers from insufficient rate capability and poor cyclability due to the low electronic conductivity.Herein,(NH_(4))_(2)V_(6)O_(16).0.9H_(2)Onanobelts with reduced graphene oxide(RGO)modification are synthesized by one-step hydrothermal reaction.Benefiting from the addition of RGO,an excellent electrochemical performance of(NH_(4))_(2)V_(6)O_(16).0.9H_(2)O@RGO nanobelts can be obtained.The(NH_(4))_(2)V_(6)O_(16).0.9H_(2)O@RGO displays a high-rate capacity and a high energy density of 386 Wh/kg at 72 W/kg.In particular,after 1000 cycles at 5 A/g,the capacity remains at 322 mAh/g with 92.8%capacity retention.In addition,the key reaction mechanisms of reversible Zn^(2+)insertion/extraction in(NH_(4))_(2)V_(6)O_(16).0.9H_(2)O@RGO are clarified.