Reversible Hydrogen Storage in a LiBH₄–C₆₀ Nanocomposite

Abstract

Hydrogen storage, fullerene, LiBH 4 , nanocomposite, fullerane Reversible hydrogen storage in a LiBH 4 :C 60 nanocomposite (70:30 wt. %) synthesized by solvent-assisted mixing has been demonstrated. D uring the solvent-assisted mixing and nanocomposite formation, a chemical reaction occurs in which the C 60 cages are significantly modified by polymerization as well as by hydrogenation (fullerane formation) in the presence of LiBH 4 . We have determined that two distinct hydrogen desorption events are observed upon rehydrogenation of the material, which are attributed to the reversible formation of a fullerane (C 60 H x ) as well as a LiBH 4 species. This system is unique in that the carbon species (C 60 ) actively participates in the hydrogen storage process which differs from the common practice of 2 melt infiltration of high surface area carbon materials with LiBH 4 (nanoconfinment effect). This nanocomposite demonstrated good reversible hydrogen storage properties as well as the ability to absorb hydrogen under mild conditions (pressures as low as 10 bar H 2 or temperatures as low as 150°C). The nanocomposite was characterized by TGA-RGA, DSC, XRD, LDI-TOF-MS, FT-IR, 1 H NMR, and APPI MS.

Composite cooperative enhancement on the hydrogen desorption kinetics of LiBH4 by co-doping with NbCl5 and hexagonal BN

“…As shown in Fig. 3(e), for the ball milled LiBH 4 sample, an activation energy of 195 kJ/mol was determined, which is in agreement with the previous report [34,35]. In the case of LiBH 4 -0.01NbCl 5 Fig.…”

“…This result confirms that NbH is formed after NbCl 5 ball milling with LiBH 4 . Based on above XRD and XPS results, the reaction equation between NbCl 5 and partial LiBH 4 during ball milling process can be written as follows [34]:…”

Hydrogen storage properties of nanoconfined LiBH 4 –NaBH 4

“…2C, as peaks a 0 , c 0 and d 0 , in which these peaks are equivalent to those presented in the bulk desorption profile. Furthermore, the onset temperature for hydrogen release is as low as 150 C, possibly assigned to the effect induced by nanoconfinement or the presence of the carbon surface, acting as a catalyst for hydrogen desorption [18]. Comparing the mixed and nanoconfined samples, it is worth noting that the hydrogen desorption profile of the physical mixed sample displays an Table 1 e Structural parameters; BET surface area, (S BET ), micro, meso and total pore volume, (V micro , V meso , V tot ), and pore size (D max ) of as prepared carbon aerogel scaffold (CA) and CO 2 -activated scaffold (CA-4).…”

“…The temperature difference between c 0 and d 0 compared to c and d may be due to the difference in the interaction between the carbon scaffold and the respective borohydrides, i.e. a possible catalytic effect [18].…”

Hydrogen Desorption Properties of Bulk and Nanoconfined LiBH4-NaAlH4

“…The improvement of hydrogen release kinetics due to the carbon scaffold, is assigned to the effect induced by nanoconfinement and possible catalytic properties of the carbon surface [36]. In addition, the DSC signal assigned to the major hydrogen desorption at T~340˝C is reduced by~140˝C as compared to that of bulk LiNa.…”