Influence of Al Content on the Atmospheric Corrosion Behaviour of Magnesium-Aluminum Alloys

The influence of AI content on the Mg-AI alloys corrosion performance during sodium chloride induced atmospheric corrosion has been studied. It was found that the corrosion rate of three Mg-AI alloys was accelerated with increasing AI content. The poor corrosion resistance was attributed to the galvanic coupling between the phase and eutectic phase or α phase and the formation of porous corrosion products.

Reconstructing proton channels via Zr-MOFs realizes highly ion-selective and proton-conductive SPEEK-based hybrid membrane for vanadium flow battery

There is an urgent need to break through the trade-off between proton conductivity and ion selectivity of proton exchange membrane(PEM)in vanadium flow battery(VFB).Proton channels in PEM are the key to controlling the ion sieving and proton conductivity in VFB.Herein,two types of proton channels are reconstructed in the hybrid membrane via introducing modified Zr-MOFs(IM-UIO-66-AS)into SPEEK matrix.Internal proton channels in IM-UIO-66-AS and interfacial proton channels between grafted imidazole groups on Zr-MOFs and SPEEK greatly improve the conductivity of the IM-UIO-66-AS/SPEEK hybrid membrane.More importantly,both reconstructed proton channels block the vanadium-ion permeation to realize enhanced ion selectivity according to the size sieving and Donnan exclusion effects,respectively.Moreover,the hybrid membrane exhibits good mechanical property and dimensional stability.Benefiting from such rational design,a VFB loading with the optimized membrane exhibits enhanced voltage efficiency of 79.9%and outstanding energy efficiency of 79.6%at 200 m A cm^(-2),and keeps a notable cycle stability for 300 cycles in the long-term cycling test.Therefore,this study provides inspiration for preparing next-generation PEMs with high ion selectivity and proton conductivity for VFB application.

Advanced dual-gradient carbon nanofibers/graphite felt composite electrode for the next-generation vanadium flow battery

Vanadium flow battery(VFB)is one of the most promising energy storage technologies because of its superior safety,reliability and cycle life,but the poor electrochemical performance at high cur-rent density limits its commercial application.Herein,an advanced design of the dual-gradient carbon nanofibers/graphite felt(DG-CNFs/GF)composite electrode is firstly proposed for the next-generation VFB with high power density.Specifically,there is a macro gradient distribution of CNFs along the thickness direction of the electrode,meanwhile a micro gradient distribution of CNFs is also existed along the ra-dial direction of a single fiber,and both the macro and micro gradient structure are verified through the physicochemical characterizations.In addition,the DG-CNFs/GF with a dual-gradient structure exhibits an excellent electrocatalytic activity and a fast mass transfer characteristic.It is worth noting that the energy conversion efficiencies,cycling stability in addition to power density of VFB with DG-CNFs/GF are much better than those with commercial GF,which make the dual-gradient DG-CNFs/GF to be a promis-ing alternative.Most importantly,the accomplishment of this work will provide a promising development direction of the highly efficient electrode for the next-generation VFB with high power density.