MXenes由于其层状结构而成为水性锌离子电池(AZIBs)的有前途的阴极材料,金属导电性,和亲水性。然而,它们具有低容量,除非它们经受电化学诱导的第二相形成,这很乏味,耗时,无法控制。在这里,我们提出了一种简单的一步表面硒化策略,用于实现先进的基于MXene的纳米杂化物。通过硒化过程,MXenes的表面金属原子转化为过渡金属硒化物(TMS),表现出高容量和优异的结构稳定性,而MXenes的内层是故意保留的。此策略适用于各种MXenes,如成功构建VSe2@V2CTx所示,TiSe2@Ti3C2Tx,和NbSe2@Nb2CTx。通常,VSe2@V2CTx提供高速率能力(132.7mAhg-1,2.0Ag-1),长期可循环性(在2.0Ag-1下600次循环后,容量保持率为93.1%),和高电容贡献(2.0mVs-1时为85.7%)。详细的实验和模拟结果表明,优异的Zn离子存储归因于V2CTx和VSe2的接合集成,这不仅显着提高了Zn离子扩散系数从4.3×10-15到3.7×10-13cm2s-1,而且还为长期循环提供了足够的结构稳定性。这项研究为开发用于高级水性金属离子电池的高性能MXene基材料提供了一种简便的方法。
MXenes are promising cathode materials for aqueous zinc-ion batteries (AZIBs) owing to their layered structure, metallic conductivity, and hydrophilicity. However, they suffer from low capacities unless they are subjected to electrochemically induced second phase formation, which is tedious, time-consuming, and uncontrollable. Here we propose a facile one-step surface selenization strategy for realizing advanced MXene-based nanohybrids. Through the selenization process, the surface metal atoms of MXenes are converted to transition metal selenides (TMSes) exhibiting high capacity and excellent structural stability, whereas the inner layers of MXenes are purposely retained. This strategy is applicable to various MXenes, as demonstrated by the successful construction of VSe2@V2CTx, TiSe2@Ti3C2Tx, and NbSe2@Nb2CTx. Typically, VSe2@V2CTx delivers high-rate capability (132.7 mA h g-1 at 2.0 A g-1), long-term cyclability (93.1% capacity retention after 600 cycles at 2.0 A g-1), and high capacitive contribution (85.7% at 2.0 mV s-1). Detailed experimental and simulation results reveal that the superior Zn-ion storage is attributed to the engaging integration of V2CTx and VSe2, which not only significantly improves the Zn-ion diffusion coefficient from 4.3 × 10-15 to 3.7 × 10-13 cm2 s-1 but also provides sufficient structural stability for long-term cycling. This study offers a facile approach for the development of high-performance MXene-based materials for advanced aqueous metal-ion batteries.