Electrochemical oxygen intercalation in La2NiO4+delta crystals
Electrochemical oxygen intercalation in La2NiO4+delta crystals
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DOI：
10.1016/0167-2738(96)00191-9
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发表时间：
1996-07-01
影响因子：
3.2
通讯作者：
Buttrey, DJ
中科院分区：
文献类型：
--
作者：
Bhavaraju, S;DiCarlo, JF;Buttrey, DJ
通过电位阶跃法在低于析氧的电位下研究了氧气从水性 KOH 电解质到 La2NiO4+δ 的电化学嵌入。第一个还原循环在整个成分范围内几乎恒定的电势下发生，并且是成核和生长行为的特征。在第一次氧化和随后的还原-氧化循环中，结果与之前针对多晶电极获得的结果类似，并且显示存在0小于或等于δ小于或等于0.06的两相区域和成分0.06小于或等于δ小于或等于0.13的单相。 P4(2)/ncm 相的 delta 类似于 0.02，化学计量范围较窄，在 d delta/dV 与 delta 数据以及电流衰减曲线的行为中很明显。对循环各个阶段的晶体进行的检查表明，形成了广泛的裂纹，这些裂纹的密度随着循环而明显增加。电位阶跃后瞬态电流的测量已用于估计单相区域 La2NiO4+delta 中氧的扩散系数。获得了多晶和单晶电极的数据。
The electrochemical intercalation of oxygen from an aqueous KOH electrolyte into La2NiO4+delta has been investigated by a potential step method at potentials below oxygen evolution. The first reduction cycle occurs at nearly constant potential for the whole composition range and is characteristic of nucleation and growth behavior. On the first oxidation and subsequent reduction-oxidation cycles, the results are similar to those obtained previously for polycrystalline electrodes and show the presence of a two-phase region for 0 less than or equal to delta less than or equal to 0.06 and a single phase with the composition 0.06 less than or equal to delta less than or equal to 0.13. The P4(2)/ncm phase with delta similar to 0.02 and a narrow range of stoichiometry, is apparent in d delta/dV versus delta data and in the behavior of the current decay curves. Examination of the crystals at various stages of cycling show the formation of extensive cracks that apparently increase in density with cycling. Measurements of the transient currents after potential steps have been used to estimate the diffusion coefficient of oxygen in La2NiO4+delta in the single phase region. Data were obtained for both polycrystalline and single crystal electrodes.