College of Materials Science and Engineering, Hunan University, Changsha, 410082, China.
State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China.
Small. 2023 Jun;19(26):e2207716. doi: 10.1002/smll.202207716. Epub 2023 Mar 20.
Metal selenides are considered as one of the most promising anode materials for Na-ion batteries owing to high specific capacity and relatively higher electronic conductivity compared with metal sulfides or oxides. However, such anodes still suffer from huge volume change upon repeated Na insertion/extraction processes and simultaneously undergo severe shuttle effect of polyselenides, thus leading to poor electrochemical performance. Herein, a facile chemical-blowing and selenization strategy to fabricate 3D interconnected hybrids built from metal selenides (MSe, M = Mn, Co, Cr, Fe, In, Ni, Zn) nanoparticles encapsulated in in situ formed N-doped carbon foams (NCFs) is reported. Such hybrids not only provide ultrasmall active nanobuilding blocks (≈15 nm), but also efficiently anchor them inside the conductive NCFs, thus enabling both high-efficiency utilization of active components and high structural stability. On the other hand, Cu-driven replacement reaction is utilized for efficiently inhibiting the shuttle effect of polyselenides in ether-based electrolyte. Benefiting from the combined merits of the unique MSe@NCFs and the utilization of the conversion of metal selenides to copper selenides, the as-obtained hybrids (MnSe as an example) exhibit superior rate capability (386.6 mAh g up to 8 A g ) and excellent cycling stability (347.7 mAh g at 4.0 A g after 1200 cycles).
金属硒化物被认为是最有前途的钠离子电池负极材料之一，因为与金属硫化物或氧化物相比，它们具有更高的比容量和相对较高的电子电导率。然而，这种负极在反复的钠插入/提取过程中仍然会经历巨大的体积变化，同时会发生多硒化物的严重穿梭效应，从而导致电化学性能不佳。在此，本文报道了一种简便的化学发泡和硒化策略，用于制备由金属硒化物（MSe，M=Mn、Co、Cr、Fe、In、Ni、Zn）纳米颗粒封装在原位形成的氮掺杂碳泡沫（NCF）中的 3D 互连混合体。这种混合体不仅提供了超小的活性纳米构建块（≈15nm），而且还能有效地将它们固定在导电的 NCF 内部，从而实现了活性成分的高效利用和高结构稳定性。另一方面，Cu 驱动的取代反应被用于有效地抑制醚基电解质中多硒化物的穿梭效应。得益于独特的 MSe@NCF 的综合优势以及利用金属硒化物转化为硒化铜，所获得的混合体（以 MnSe 为例）表现出优异的倍率性能（高达 8A g 时为 386.6 mAh g）和出色的循环稳定性（在 4.0 A g 下循环 1200 次后为 347.7 mAh g）。
