Mechanism of Mn on inhibiting Fe-caused magnesium corrosion

In the present study,to understand the mechanism of Mn on inhibiting Fe-caused Mg corrosion,the corrosion behaviour of commercial pure Mg and Mg-6 Mn alloy in 0.6 M NaCl solution is investigated.It is found that in Mg-6 Mn alloy,Fe impurity is incorporated into Mn to form Mn(Fe)phase with Fe as solid solute.The initial galvanic corrosion cannot be reduced through converting Fe-rich phase to Mn(Fe)phase,since Mn(Fe)phase also has relatively strong cathodic activity and has much larger volume fraction than Fe-rich phase.However,the cathodic activation behaviour of pure Mg is inhibited.The cathodic activity even decreases for Mg-Mn alloy with increased exposure time,due to the reduced cathodic HER at the Mn(Fe)particles.Mn can be oxidized at the OCP of Mg-6 Mn alloy,resulting in relatively dense Mn-rich corrosion film on particle surface,which separates the particle from the electrolyte and,consequently,inhibits HER.

Synthesis and Electrocatalytic Properties of Complex Oxides Containing Lanthanum

A series of perovskite-type complex oxides LaNi1-xRuxO3 were prepared and studied by means of XRD. The effects of some factors on th complex oxides were discussed. Each kind of those perovskite-type complex oxides was used to prepare cathode by composite-electroplating technique. The cathodes were electrochemically charactrized. The results show that these novel cathode exhibit high activities and excellent stabilities during long-term continuous electrolysis with some current interruptions.

Recent advances in cathodes for all-solid-state lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries have been regarded as the candidate for the next-generation energy storage system due to the high theoretical specific capacity(1675 m Ah/g), energy density(2600 Wh/kg)and the abundance of elemental sulfur, but the application of Li-S batteries is impeded by a series of problems. Recently, all-solid-state Li-S batteries(ASSLSBs) have drawn great attention because many drawbacks such as safety issues caused by metallic lithium anodes and organic liquid electrolytes can be overcome through the use of solid-state electrolytes(SEs). However, not only the problems brought by sulfur cathodes still exist, but more trouble arouses from the interfaces between SEs and cathodes, hampering the practical application of ASSLSBs. Therefore, in order to deal with the problems, enormous endeavors have been done on ASSLSB cathodes during the past few decades, including engineering of cathode active materials, cathode host materials, cathode binder materials and cathode structures. In this review, the electrochemical mechanism and existing problems of ASSLSBs are briefly introduced. Subsequently, the strategies for developing cathode materials and designing cathode structures are presented. Then there follows a brief discussion of SE problems and expectations, and finally, the challenges and perspectives of ASSLSBs are summarized.

Enhanced photoelectrocatalytic decomplexation of Ni-EDTA and simultaneous recovery of metallic nickel via TiO_(2)/Ni-Sb-SnO_(2) bifunctional photoanode and activated carbon fiber cathode

In order to enhance Ni-EDTA decomplexation and Ni recovery via photoelectrocatalytic (PEC)process,TiO_(2)/Ni-Sb-SnO_(2)bifunctional electrode was fabricated as the photoanode and activated carbon fiber (ACF) was introduced as the cathode.At a cell voltage of 3.5 V and initial solution pH of 6.3,the TiO_(2)/Ni-Sb-SnO_(2)bifunctional photoanode exhibited a synergetic effect on the decomplexation of Ni-EDTA with the pseudo-first-order rate constant of 0.01068 min^(-1)with 180 min by using stainless steel (SS) cathode,which was 1.5 and 2.4times higher than that of TiO_(2)photoanode and Ni-Sb-SnO_(2)anode,respectively.Moreover,both the efficiencies of Ni-EDTA decomplexation and Ni recovery were improved to 98%from 86%and 73%from 41%after replacing SS cathode with ACF cathode,respectively.Influencing factors on Ni-EDTA decomplexation and Ni recovery were investigated and the efficiencies were favored at acidic condition,higher cell voltage and lower initial Ni-EDTA concentration.Ni-EDTA was mainly decomposed via·OH radicals which generated via the interaction of O_(3),H_(2)O_(2),and UV irradiation in the contrasted PEC system.Then,the liberated Ni^(2+)ions which liberated from Ni-EDTA decomplexation were eventually reduced to metallic Ni on the ACF cathode surface.Finally,the stability of the constructed PEC system on Ni-EDTA decomplexation and Ni recovery was exhibited.

Effect of Mn Addition and Heat Treatment on the Corrosion Behaviour of Mg-Ag-Mn Alloy

The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of Mg-Ag-Mn alloys is investigated with the underlying microstructural factors examined. The Mg-Ag alloy with 2 wt% Mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of Mn results in α-Mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-Mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.

A bi-component polyoxometalate-derivative cathode material showed impressive electrochemical performance for the aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries are recently gaining incremental attention because of low cost and material abundance,but their development is plagued by limited choices of cathode materials with satisfactory cycling performance.The polyoxometalates perform formidable redox stability and able to participate in multi-electron transfer,which was well-suited for energy storage.Herein,a bicomponent polyoxometalate-derivative KNiVO(K_(2)[Ni(H_(2)O)_(6)]_(2)[V_(10)O_(28)]·_(4)H_(2)O polyoxometalates after annealing)is firstly demonstrated as a cathode material for aqueous ZIBs.The layered KV_(3)O_(8)(KVO)In the bi-component material constitutes Zn^(2+) migration and storage channels(K^(+) were substantially replaced by Zn^(2+) in the activation phase),and the three-dimensional NiV_(3)O_(8)(NiVO)part acts as skeleton to stabilize the ion channels,which assist the cell to demonstrate a high-rate capacity and specific energy of229.4 mAh/g and satisfactory cyclability(capacity retention of 99.1%after 4500 cycles at a current density of 4 A/g).These results prove the feasibility of POM as cathode materials precursor and put forward a novel pattern of the Zn^(2+)storage mechanism in the activated-KNiVO clusters,which also provide a new route for selecting or designing high-performance cathode for aqueous ZIBs and other advanced battery systems.