He Hanna, Zhang Hehe, Huang Dan, Kuang Wei, Li Xiaolong, Hao Junnan, Guo Zaiping, Zhang Chuhong
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute, Sichuan University, Chengdu, 610065, China.
State Key Lab of Physical Chemistry of Solid Surfaces, College of Materials, Xiamen University, Xiamen, 361005, China.
Adv Mater. 2022 Apr;34(15):e2200397. doi: 10.1002/adma.202200397. Epub 2022 Mar 1.
Metallic-phase selenide molybdenum (1T-MoSe ) has become a rising star for sodium storage in comparison with its semiconductor phase (2H-MoSe ) owing to the intrinsic metallic electronic conductivity and unimpeded Na diffusion structure. However, the thermodynamically unstable nature of 1T phase renders it an unprecedented challenge to realize its phase control and stabilization. Herein, a plasma-assisted P-doping-triggered phase-transition engineering is proposed to synthesize stabilized P-doped 1T phase MoSe nanoflower composites (P-1T-MoSe NFs). Mechanism analysis reveals significantly decreased phase-transition energy barriers of the plasma-induced Se-vacancy-rich MoSe from 2H to 1T owing to its low crystallinity and reduced structure stability. The vacancy-rich structure promotes highly concentrated P doping, which manipulates the electronic structure of the MoSe and urges its phase transition, acquiring a high transition efficiency of 91% accompanied with ultrahigh phase stability. As a result, the P-1T-MoSe NFs deliver an exceptional high reversible capacity of 510.8 mAh g at 50 mA g with no capacity fading over 1000 cycles at 5000 mA g for sodium storage. The underlying mechanism of this phase-transition engineering verified by profound analysis provides informative guide for designing advanced materials for next-generation energy-storage systems.
与半导体相（2H-MoSe₂）相比，金属相硒化钼（1T-MoSe₂）因其固有的金属电子导电性和畅通无阻的钠扩散结构，已成为储钠领域的一颗新星。然而，1T相的热力学不稳定性质使其在实现相控制和稳定方面面临前所未有的挑战。在此，我们提出了一种等离子体辅助的P掺杂触发相变工程，以合成稳定的P掺杂1T相MoSe₂纳米花复合材料（P-1T-MoSe₂ NFs）。机理分析表明，由于等离子体诱导的富硒空位MoSe₂结晶度低且结构稳定性降低，其从2H到1T的相变能垒显著降低。富空位结构促进了高浓度的P掺杂，从而操纵了MoSe₂的电子结构并促使其相变，获得了91%的高转变效率以及超高的相稳定性。结果，P-1T-MoSe₂ NFs在50 mA g下具有510.8 mAh g的超高可逆容量，在5000 mA g下进行1000次循环储钠时没有容量衰减。通过深入分析验证了这种相变工程的潜在机制，为设计下一代储能系统的先进材料提供了有益的指导。
