首次研究高价银氧化物Ag3O4(可看作为由Ag(Ⅲ)和Ag(Ⅱ)*组成)在碱性水溶液中的电化学性质和反应机理.循环伏安和XRD测试表明,Ag3O4在碱性溶液中的电化学还原过程比较复杂:在较慢的放电条件下,Ag3O4中的Ag(Ⅲ)按照Ag(Ⅲ)→Ag(Ⅱ)→Ag(Ⅰ)→Ag反应途径逐步还原为单质银;在较快的放电条件下,Ag(Ⅲ)可以直接被还原为Ag(Ⅰ),即Ag(Ⅲ)→Ag(Ⅰ)→Ag.而Ag(Ⅱ)*可直接还原成金属Ag.Ag3O4的理论放电容量可以达到553.1 mAh/g,比通常锌-氧化银电池所用AgO的电容量高出27.8%.在119C放电倍率下,Ag3O4的放电容量依然达到理论容量的83%.显示了作为新型化学电源材料的应用前景.
The electrochemical properties of high-valence silver oxide Ag_(3)O_(4)in alkaline solution were investigated for the first time and the reduction mechanism of Ag_(3)O_(4) was proposed.It can be recognized that Ag_(3)O_(4)consists of_()Ag(Ⅲ) and Ag(Ⅱ)~(*).From the results of voltammetry and XRD experiments it was found that the reduction process of Ag_(3)O_(4) was more complicated.It could be electrochemically reduced through the series reactions of Ag(Ⅲ) →Ag(Ⅱ) →Ag(Ⅰ) →Ag(O) at low discharge rate or Ag(Ⅲ) →Ag(Ⅰ) →Ag(O) at higher discharge rate.And the Ag(Ⅱ)~(*) could be reduced to Ag directly at low potential region.In addition,it is interesting to note that Ag_(3)O_(4) presents the theoretical specific discharge capacity of 553.0mAh/g at high discharge rate,which is 27.8% higher than that of the commonly used cathodic material AgO in zinc/silver oxide battery.Under high discharge rate of 119C,Ag_(3)O_(4) still presents the specific discharge capacity as high as 83% of theoretical value.Ag_(3)O_(4) may have the attractive future for the use in alkaline batteries.
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