Hydrogen Desorption Properties of Bulk and Nanoconfined LiBH4-NaAlH4

Abstract

Nanoconfinement of 2LiBH 4 -NaAlH 4 into a mesoporous carbon aerogel scaffold with a pore size, BET surface area and total pore volume of D max = 30 nm, S BET = 689 m 2 /g and V tot = 1.21 mL/g, respectively is investigated. Nanoconfinement of 2LiBH 4 -NaAlH 4 facilitates a reduction in the temperature of the hydrogen release by 132˝C, compared to that of bulk 2LiBH 4 -NaAlH 4 and the onset of hydrogen release is below 100˝C. The reversible hydrogen storage capacity is also significantly improved for the nanoconfined sample, maintaining 83% of the initial hydrogen content after three cycles compared to 47% for that of the bulk sample. During nanoconfinement, LiBH 4 and NaAlH 4 reacts to form LiAlH 4 and NaBH 4 and the final dehydrogenation products, obtained at 481˝C are LiH, LiAl, AlB 2 and Al. After rehydrogenation of the nanoconfined sample at T = 400˝C and p(H 2 ) = 126 bar, amorphous NaBH 4 is recovered along with unreacted LiH, AlB 2 and Al and suggests that NaBH 4 is the main compound that can reversibly release and uptake hydrogen.

LiAlH4 as a “Microlighter” on the Fluorographite Surface Triggering the Dehydrogenation of Mg(BH4)2: Toward More than 7 wt % Hydrogen Release below 70 °C

“…Such results suggest that FGi may act as “barriers” in ball milling to prevent the interactions between Mg­(BH 4 ) 2 and LiAlH 4 . Interestingly, such an effect has not been reported in other multihydride systems with carbon-based additives. , …”

“…Interestingly, such an effect has not been reported in other multihydride systems with carbon-based additives. 32,33 FTIR measurements were performed to reveal the bonding environments of as-prepared samples, as displayed in Figure 2. According to the FTIR results, as-prepared Mg(BH 4 ) 2 exhibits three major absorbance peaks at 2291, 1265, and 1124 cm −1 , which are in consistence with a previous report.…”

Recent Development of Lithium Borohydride‐Based Materials for Hydrogen Storage

“…[121] Nanoconfinement of 2LiBH 4 -NaAlH 4 enabled an onset of hydrogen release below 100 ºC, which was 132 ºC lower than that of bulk system. [122] For the ternary system of LiBH 4 -MgH 2 -NaAlH 4 , nanoconfinement not only converged multiple-step decomposition into a single step but also largely reduced the dehydrogenation temperature, approximately by 70 ºC regarding the last dehydrogenation step. [123] The hydrogen storage properties of eutectic mixed borohydride systems were also significantly improved by nanoconfinement.…”

Lightweight hydrides nanocomposites for hydrogen storage: Challenges, progress and prospects

“…Considerable efforts have been made to explore the hydrogenation and dehydrogenation performances of lightweight metal alanates [180][181][182][183][184][185]. Many effective approaches have been proposed to enhance hy- drogen storage performances by nanoscaling [186,187], wet chemistry infiltration [188][189][190], adding dopants [191][192][193][194][195], and mixing in the lightweight metal hydride [189,[196][197][198]. In this part, we will summarize the challenges and progresses of lightweight metal alanates and focus on the effects of nanoscaling and multifarious dopants.…”