A series of Ni(OH)₂/Co(OH)₂ core/shell nanoplatelets with varying shell thickness (0.5–4.1 nm) are systematically investigated with a combination of scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX), x-ray diffraction (XRD), in situ and ex situ x-ray absorption fine structure spectroscopy (XAFS), and electrochemical tests. Structure-properties correlations reveal that electrochemical behavior and reversibility of Co(OH)₂ redox conversion depends non-linearly on the average shell thickness, with the best performance (99.6% of theoretical capacity of the composite material, 10% improvement over the performance of pristine Ni(OH)₂ nanoparticles) is achieved at shell thickness of 1.9 ± 0.3 nm. Two fundamental phenomena are suggested to be responsible for the superior performance: templated shell deposition and galvanic coupling of core and shell materials. Homogeneous deposition of the shell is confirmed with XRD, SEM and EDX, while lattice templating effect was suggested from XAFS results showing that Co-M and Co-O distances are close to those of the Ni(OH)₂ lattice in thin shells and shift gradually towards values of bulk Co(OH)₂ as the shell thickness increases. From a combination of electrochemical and structural characterization of these composite nanomaterials, including in situ XAFS, galvanic coupling between the shell and core is proposed as a material activation mechanism, which explains the limited reversibility of the Co(II)/Co(III) oxidation in some cases. Proposed performance enhancement mechanisms are applicable for design of other core/shell electrode materials.

结合扫描电子显微镜（SEM）和能量色散X射线分析（EDX），系统地研究了一系列具有不同壳厚度（0.5–4.1 nm）的Ni（OH）₂ / Co（OH）₂核/壳纳米片），X射线衍射（XRD），原位和异位X射线吸收精细结构光谱（XAFS）以及电化学测试。结构-性质的相关性表明，Co（OH）₂氧化还原转化的电化学行为和可逆性与平均壳厚度呈非线性关系，具有最佳性能（复合材料理论容量的99.6％，比复合材料的性能提高10％）原始Ni（OH）₂壳厚度为1.9±0.3 nm时获得）。建议两个基本现象来负责获得优异的性能：模板化的壳层沉积以及核和壳层材料的电流耦合。XRD，SEM和EDX证实了壳的均匀沉积，而XAFS结果表明晶格模板效应表明，Co-M和Co-O距离接近薄壳中Ni（OH）₂晶格的距离并发生漂移。随着壳厚度的增加，逐渐趋向于本体Co（OH）_2的值。从这些复合纳米材料的电化学和结构表征的结合，包括原位XAFS，壳和核之间的电流耦合被提议为一种材料激活机制，这解释了在某些情况下Co（II）/ Co（III）氧化的有限可逆性。提议的性能增强机制适用于其他核/壳电极材料的设计。