Owing to the relatively high theoretical capacities, transition metal phosphides (TMPs) are attracting much attention for potassium and lithium storage. Nonetheless, the severe volume change and sluggish diffusion kinetics caused by the repeated intercalation and de-intercalation processes of Li+/K+, impede their further development. Herein, the ultrafine Ni2P nanoparticles were encapsulated inside the tubular mesoporous carbon pore channels (named as Ni2P@SCC) via the confined growth strategy. The obtained Ni2P@SCC possesses small particle size of Ni2P (∼5.4 nm), high specific surface area and monodisperse nature of Ni2P nanoparticles even at high temperature of 600 °C. Its novel nanostructure can not only promote the electrical conductivity but also protect the integrity of Ni2P nanoparticles during cycling. Thus, the Ni2P@SCC anode displays high performance for potassium (210 mAh/g) and lithium (340 mAh/g) storage at 6.0 A/g. The EIS, GITT and ex-situ TEM results further suggest the immobilization and monodispersity of Ni2P nanoparticles within the tubular mesoporous carbon pore channels contribute to a charge storage process without agglomeration. Furthermore, this work can provide an effective strategy for rationally designing construction of other materials with small particle size, which will interest for energy and catalysis area.

中文翻译：

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超细 Ni2P 纳米颗粒的介孔碳管诱导的弹性约束，用于增强钾和锂的储存


由于相对较高的理论容量，过渡金属磷化物 （TMP） 在钾和锂储存方面引起了广泛关注。尽管如此，Li+/K+ 的反复插层和脱层过程引起的剧烈体积变化和缓慢的扩散动力学阻碍了它们的进一步发展。在此，超细 Ni2P 纳米颗粒通过受限生长策略封装在管状介孔碳孔通道（命名为 Ni2P@SCC）内。所得Ni2P@SCC即使在 600 °C 的高温下也具有小粒径的 Ni2P （∼5.4 nm）、高比表面积和 Ni2P 纳米颗粒的单分散性。 其新颖的纳米结构不仅可以促进导电性，还可以保护 Ni2P 纳米颗粒在循环过程中的完整性。因此，Ni2P@SCC负极在 6.0 A/g 的钾 （210 mAh/g） 和锂 （340 mAh/g） 储存方面表现出高性能。EIS、GITT 和非原位 TEM 结果进一步表明，Ni2P 纳米颗粒在管状介孔碳孔通道内的固定化和单分散性有助于电荷储存过程而不会团聚。此外，这项工作可以为合理设计其他小粒径材料的构建提供有效的策略，这将在能源和催化领域发挥作用。