Catalyzed Nano-Framework Stablized High Density Reversible Hydrogen Storage Systems

Tang, Xia¹  Opalka, Susanne M.  Mosher, Daniel A  Laube, Bruce L  Brown, Ronald J  Vanderspurt, Thomas H  Arsenault, Sarah  Wu, Robert  Strickler, Jamie  Ronnebro, Ewa  Boyle, Tim  Cordaro, Joseph 

[1] value too long for type character varying(50)

关键词: Hydrogen Storage;    Nano-Framework;    Metal Borohydrides;    Aerogels;   

DOI  :  10.2172/1054211
RP-ID  :  DOE/GO/17030-1
PID  :  OSTI ID: 1054211

学科分类：再生能源与代替技术

美国|英语

来源: SciTech Connect

【 摘 要 】

A wide range of high capacity on-board rechargeable material candidates have exhibited non-ideal behavior related to irreversible hydrogen discharge / recharge behavior, and kinetic instability or retardation. This project addresses these issues by incorporating solvated and other forms of complex metal hydrides, with an emphasis on borohydrides, into nano-scale frameworks of low density, high surface area skeleton materials to stabilize, catalyze, and control desorption product formation associated with such complex metal hydrides. A variety of framework chemistries and hydride / framework combinations were investigated to make a relatively broad assessment of the method's potential. In this project, the hydride / framework interactions were tuned to decrease desorption temperatures for highly stable compounds or increase desorption temperatures for unstable high capacity compounds, and to influence desorption product formation for improved reversibility. First principle modeling was used to explore heterogeneous catalysis of hydride reversibility by modeling H₂ dissociation, hydrogen migration, and rehydrogenation. Atomic modeling also demonstrated enhanced NaTi(BH₄)₄ stabilization at nano-framework surfaces modified with multi-functional agents. Amine multi-functional agents were found to have more balanced interactions with nano-framework and hydride clusters than other functional groups investigated. Experimentation demonstrated that incorporation of Ca(BH₄)₂ and Mg(BH₄)₂ in aerogels enhanced hydride desorption kinetics. Carbon aerogels were identified as the most suitable nano-frameworks for hydride kinetic enhancement and high hydride loading. High loading of NaTi(BH₄)₄ ligand complex in SiO₂ aerogel was achieved and hydride stability was improved with the aerogel. Although improvements of desorption kinetics was observed, the incorporation of Ca(BH₄)₂ and Mg(BH₄)₂ in nano-frameworks did not improve their H₂ absorption due to the formation of stable alkaline earth B₁₂H₁₂ intermediates upon rehydrogenation. This project primarily investigated the effect of nano-framework surface chemistry on hydride properties, while the effect of pore size is the focus area of other efforts (e.g., HRL, Sandia National Laboratories (SNL) etc.) within the Metal Hydride Center of Excellence (MHCoE). The projects were complementary in gaining an overall understanding of the influence of nano-frameworks on hydride behavior.