An investigation of electronic property and high pressure phase stability of SmN has been conducted using first principles calculations based on density functional theory. The elec- tronic properties of Stun show a striking feature of a half metal, the majority-spin electrons are metallic and the minority-spin electrons are semiconducting. It was found that Stun undergoes a pressure-induced phase transition from NaCl-type （B1） to CsCl-type structure （B2） at 117 GPa. The elastic constants of Stun satisfy Born conditions at ambient pressure, indicating that B1 phase of SmN is mechanically stable at 0 GPa. The result of phonon spectra shows that B1 structure is dynamically stable at ambient pressure, which agrees with the conclusion derived from the elastic constants.
利用聚乙烯吡咯烷酮(PVP)作为聚合物配位剂和燃料,通过溶胶-凝胶PVP辅助燃烧法在800℃到900℃合成了具有不同形貌的锂离子电池负极材料Li_4Ti_5O_(12)。主要研究了不同煅烧温度对材料结构、形貌以及电化学性能的影响。利用XRD、SEM和充放电测试表征Li_4Ti_5O_(12)的结构、形貌及其充放电和倍率性能。研究结果表明材料为尖晶石型结构,颗粒大小分布均匀,颗粒在500 nm左右。在800℃焙烧8 h得到的Li_4Ti_5O_(12)首次充放电容量为167.4 m Ah/g。
