Sodium-ion batteries (SIBs) are promising power sources due to the low cost and abundance of battery-grade sodium resources, while practical SIBs suffer from intrinsically sluggish diffusion kinetics and severe volume changes of electrode materials. Metal-organic framework (MOFs) derived carbonaceous metal compound offer promising applications in electrode materials due to their tailorable composition, nanostructure, chemical and physical properties. Here, we fabricated hierarchical MOF-derived carbonaceous nickel selenides with bi-phase composition for enhanced sodium storage capability. As MOF formation time increases, the pyrolyzed and selenized products gradually transform from a single-phase Ni₃Se₄ into bi-phase NiSe_x then single-phase NiSe₂, with concomitant morphological evolution from solid spheres into hierarchical urchin-like yolk-shell structures. As SIBs anodes, bi-phase NiSe_x@C/CNT-10h (10 h of hydrothermal synthesis time) exhibits a high specific capacity of 387.1 mAh/g at 0.1 A/g, long cycling stability of 306.3 mAh/g at a moderately high current density of 1 A/g after 2,000 cycles. Computational simulation further proves the lattice mismatch at the phase boundary facilitates more interstitial space for sodium storage. Our understanding of the phase boundary engineering of transformed MOFs and their morphological evolution is conducive to fabricate novel composites/hybrids for applications in batteries, catalysis, sensors, and environmental remediation.

钠离子电池（SIB）由于低成本和丰富的电池级钠资源而成为有前途的电源，而实际的SIB则固有地具有扩散动力学缓慢和电极材料体积变化大的缺点。金属有机骨架（MOF）衍生的含碳金属化合物因其可定制的组成，纳米结构，化学和物理特性而在电极材料中提供了有希望的应用。在这里，我们制造了具有两相成分的分层MOF衍生的碳质硒化镍，以增强钠的储存能力。随着MOF形成时间的增加，热解和硒化产物逐渐从单相Ni ₃ Se ₄转变为双相NiSe _x然后转变为单相NiSe ₂，伴随着形态的变化，从固体球体演变为类似海胆的蛋黄壳结构。作为SIBs阳极，双相NiSe _x @ C / CNT-10h（水热合成时间为10 h）在0.1 A / g的条件下显示出387.1 mAh / g的高比容量，在中等水平下显示出306.3 mAh / g的长循环稳定性2,000次循环后1 A / g的高电流密度。计算仿真进一步证明，相边界处的晶格失配有助于更多的间隙空间用于钠存储。我们对转化MOF的相边界工程及其形态演变的理解有助于制造用于电池，催化，传感器和环境修复的新型复合材料/混合材料。