Li Zhenglong, Xian Kaicheng, Gao Mingxia, Wang Shun, Qu Shanqing, Wu Meihong, Gan Jiantuo, Yang Yaxiong, Zhang Xin, Sun Wenping, Liu Yongfeng, Pan Hongge
Institute of Science and Technology for New Energy, Xi'an Technological University, Xi'an 710021, PR China.
State Key Laboratory of Silicon and Advanced Semiconductor Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, PR China.
ACS Appl Mater Interfaces. 2024 Sep 11;16(36):47571-47580. doi: 10.1021/acsami.4c08705. Epub 2024 Sep 2.
To achieve large-scale hydrogen storage for growing high energy density and long-life demands in end application, the 2LiBH-MgH (LMBH) reactive hydride system attracts huge interest owing to its high hydrogen capacity and thermodynamically favorable reversibility. The sluggish dehydrogenation kinetics and unsatisfactory cycle life, however, remain two challenges. Herein, a bimetallic titanium-niobium oxide with a two-dimensional nanoflake structure (2D TiNbO) is selected elaborately as an active precursor that transforms into TiB and NbB with ultrafine size and good dispersion in the LMBH system as highly efficient catalysts, giving rise to excellent kinetic properties with long-term cycling stability. For the LMBH system added with 5 wt% 2D TiNbO, 9.8 wt% H can be released within 20 min at 400 °C, after which the system can be fully hydrogenated in less than 5 min at 350 °C and 10 MPa H. Moreover, a dehydrogenation capacity of 9.4 wt% can be maintained after 50 cycles corresponding to a retention of 96%, being the highest reported to date. The positive roles of TiB and NbB for kinetics and recyclability are from their catalytic nucleation effects for MgB, a main dehydrogenation phase of LMBH, thus reducing the apparent activation energy, suppressing the formation of thermostable LiBH byproducts, and inhibiting the hydride coarsening. This work develops an advanced LMBH system, bringing hope for high-capacity, fast-response, and long-life hydrogen energy storage.
为了满足终端应用中不断增长的高能量密度和长寿命需求，实现大规模储氢，2LiBH-MgH（LMBH）反应性氢化物体系因其高储氢容量和热力学上有利的可逆性而备受关注。然而，缓慢的脱氢动力学和不尽人意的循环寿命仍然是两个挑战。在此，精心选择了一种具有二维纳米片状结构的双金属钛铌氧化物（2D TiNbO）作为活性前驱体，它在LMBH体系中转变为尺寸超小且分散良好的TiB和NbB，作为高效催化剂，具有优异的动力学性能和长期循环稳定性。对于添加了5 wt% 2D TiNbO的LMBH体系，在400 °C下20分钟内可释放9.8 wt%的氢，之后在350 °C和10 MPa氢气压力下不到5分钟即可完全氢化。此外，50次循环后脱氢容量可维持在9.4 wt%，保留率为96%，是迄今为止报道的最高值。TiB和NbB对动力学和可循环性的积极作用源于它们对LMBH主要脱氢相MgB的催化成核作用，从而降低了表观活化能，抑制了热稳定LiBH副产物的形成，并抑制了氢化物粗化。这项工作开发了一种先进的LMBH体系，为高容量、快速响应和长寿命的氢能存储带来了希望。
