Investigation of solid state hydrogen storage performances of novel NaBH4/Ah-BN nanocomposite as hydrogen storage medium for fuel cell applications

Abstract

In the era of chaotic global warming and climate change, the hunt for alternative energy sources for fossil fuel has become an intense topic. The most viable clean, green and alternative energy carrier is hydrogen that can meet out the challenges posed towards energy scarcity. So, the present work focus on the effective storing of hydrogen on non-carboneous (Ah-BN) and hydrogen rich metal hydride (NaBH4) based storage medium. where a facile chemical impregnated method was adopted for the preparation of NaBH4/Ah-BN nanocomposite. The structural, morphological, elemental composition and specific surface area analysis of the prepared NaBH4/Ah-BN nanocomposite confirms the presence of NaBH4 wrapped around Ah-BN and enhanced specific surface area of 154.4 m2 g −1 (NaBH4/Ah-BN) from 68.2 m2 g −1 (Ah-BN). The presence of NaBH4 not only increases the specific surface area but also increases the pore volume thereby creating more defects. In contrast the presence of Ah-BN drastically reduces the decomposition temperature of NaBH4. The amount of stored hydrogen (Sievert’s-like hydrogenation setup) was 3.8 wt% at 119 °C and the binding energy falls in the recommended range (0.33 −0.50 eV) of US-Department of Energy (DOE) 2025 targets. All the thermal analysis [thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and temperature-programmed desorption (TPD)] ensures the two-step dehydrogenation for NaBH4/Ah-BN. Moreover, the utilization of NaBH4/Ah-BN as an electrode to store hydrogen electrochemically reveals the attainment of 2550 mAh/g discharge capacity during 15 cycles that equals to 4.10 wt% hydrogen storage capacity. Hence, these excellent characteristics proved that the prepared NaBH4/Ah-BN nanocomposite may serve as an excellent weakly chemisorbed hydrogen storage system and electrode material to store hydrogen electrochemically in the realm of Hydrogen Fuel cells.