3NaBH4/ErF3复合储氢材料的制备及吸放氢特性

采用高能球磨法制备了3NaBH4/ErF3复合储氢材料, 并研究了其相结构和储氢性能. X射线衍射(XRD)显示, NaBH4和ErF3在球磨过程中未发生反应; 同步热分析(TG-DSC)测试结果表明, 3NaBH4/ErF3体系在420℃开始放氢, 比相同测试条件下纯NaBH4的放氢温度降低了约100℃, 放氢量为3.06%(质量分数). 压力-成分-温度(Pressure-Composition-Temperature, PCT)性能测试结果显示, 3NaBH4/ErF3复合储氢材料在较低的温度(355~413℃)及平台氢压(<1 MPa)下即拥有良好的可逆吸放氢性能, 最高可逆吸氢量可达到2.78%(质量分数), 吸氢后体系重新生成了NaBH4相. 计算得吸氢焓变仅为-36.8 kJ/mol H2; 而放氢焓变为-180.8 kJ/mol H2. NaBH4在ErF3的作用下提高了热动力学性能, 并实现了可逆吸放氢.

Synthesis and Hydrogen Sorption Properties of 3NaBH4/ErF3 Hydrogen Storage Composite

3NaBH4/ErF3 hydrogen storage composite was prepared through ball milling method and its phase structure and hydrogen sorption properties were investigated. It is shown that NaBH4 did not react with ErF3 during ball milling. The dehydrogenation temperature of the composite, measured by thermo gravimetric-diffe-rential scanning calorimetry(TG-DSC), is 420℃, which is about 100℃ lower than the dehydrogenation temperature of pure NaBH4. Mass loss of the composite is about 3.06%. Pressure-Composition-Temperature (PCT) tests revealed that the composite has outstanding reversible hydrogen sorption performance at moderate temperatures (355-413℃) and under quite low hydrogenation plateau pressures(<1 MPa) the maximum hydrogen storage capacity of the composite can reach up to 2.78%. It was found that NaBH4 was regenerated during hydrogenation. Based on the PCT analyses, the hydrogenation enthalpy of the composite is determined to be -36.8 kJ/mol H2, while the dehydrogenation enthalpy is -180.8 kJ/mol H2. The addition of ErF3 into NaBH4 improves the thermodynamic performance of NaBH4 and forms a reversible hydrogen storage composite.