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Tunable Surface Selenization on MoO2 -Based Carbon Substrate for Notably Enhanced Sodium-Ion Storage Properties.
Small ( IF 13.0 ) Pub Date : 2020-09-20 , DOI: 10.1002/smll.202001905
Fanyan Zeng 1 , Maohui Yu 1 , Wanting Cheng 1 , Wenxiu He 1 , Yang Pan 2 , Yaohui Qu 1 , Cailei Yuan 1
Affiliation  

Transition metal chalcogenides with high theoretical capacity are promising conversion‐type anode materials for sodium ion batteries (SIBs), but often suffer from unsatisfied cycling stability (hundreds of cycles) caused by structural collapse and agglomerate. Herein, a rational strategy of tunable surface selenization on highly crystalline MoO2‐based carbon substrate is designed, where the sheet‐like MoSe2 can be coated on the surface of bundle‐like N‐doped carbon/granular MoO2 substrate, realizing partial transformation from MoO2 to MoSe2, and creating b‐NC/g‐MoO2@s‐MoSe2‐10 with robust hierarchical MoO2@MoSe2 heterostructures and strong chemical couplings (MoC and MoN). Such well‐designed architecture can provide signally improved reaction kinetics and reinforced structural integrity for fast and stable sodium‐ion storage, as confirmed by the ex situ results and kinetic analyses as well as the density functional theory calculations. As expected, the b‐NC/g‐MoO2@s‐MoSe2‐10 delivers splendid rate capability and ultralong cycling stability (254.2 mAh g−1 reversible capacity at 5.0 A g−1 after 6000 cycles with 89.0% capacity retention). Therefore, the tunable surface strategy can provide new insights for designing and constructing heterostructures of transition metal chalcogenides toward high‐performance SIBs.

中文翻译:

基于MoO2的碳基板上的可调表面硒化,可显着增强钠离子存储性能。

具有高理论容量的过渡金属硫属化物是用于钠离子电池(SIB)的有前途的转换类型阳极材料,但通常会因结构崩溃和团聚而导致循环稳定性(数百个循环)不令人满意。在此,设计了一种在高度结晶的基于MoO 2的碳基底上可调表面硒化的合理策略,其中可以将片状MoSe 2涂覆在成束的N掺杂碳/颗粒状MoO 2基底的表面上,从而实现部分硒化。从MoO 2转换为MoSe 2,并使用健壮的MoO 2分层创建b ‐NC / g-MoO 2 @ s-MoSe 2 -10@MoSe 2个异质结构和强化学偶联(沫 C和沫 N)。异位结果和动力学分析以及密度泛函理论计算证实,这种精心设计的体系结构可提供信号改善的反应动力学和增强的结构完整性,以实现快速,稳定的钠离子存储。如预期的那样,b ‐NC / g-MoO 2 @ s-MoSe 2 ‐10具有出色的速率能力和超长的循环稳定性(6000次循环后,在5.0 A g -1下可逆容量为254.2 mAh g -1可逆容量,89.0%的容量保留率)。因此,可调谐表面策略可为设计和构建过渡金属硫族化物朝向高性能SIB的异质结构提供新的见解。
更新日期:2020-10-16
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