磷铁钠矿型NaFePO_4/C正极的制备及储钠性能

通过溶胶凝胶法制备了磷铁钠矿型NaFePO_4/C钠离子电池正极材料,然后利用X射线衍射(XRD)、扫描电子显微镜(SEM)以及X射线能量色散光谱(EDX)研究了磷铁钠矿型NaFePO_4/C正极材料的微观结构及形貌;并进一步利用恒流充/放电及循环伏安(CV)技术测试了其电化学性能。结果表明:所制备的磷铁钠矿型NaFePO_4/C正极在0.1 C时的首次放电比容量约为26.9 m Ah/g,经过50次循环后,电极的容量保持率为98.6%,而且在1.0 C时的可逆放电比容量仍为15.5 m Ah/g,表现了满意的充/放电循环稳定性和倍率性能,在对电池容量要求不高的应用场合中优势更加明显。

马脾铁蛋白铁核表层磷铁组成稳定性

马脾铁蛋白络合Ｆｅ２＋的能力与它的铁核表层磷酸盐和Ｆｅ３＋组成含量有关．ＯＨ－参与铁核表层组成，并迫使铁蛋白释放Ｆｅ３＋．用强还原剂还原铁核表层时，铁蛋白只能释放磷酸盐．在Ｆｅ２＋、磷酸盐和氧化剂存在下，铁蛋白能贮存原铁核总磷酸盐量的６０％的磷．

Preparation and Investigation on Lattice Distortion and Electrochemical Performances of Li0.95Na0.05FePO4/C

Na^＋ doped sample Li0.95Na0.05FePO4 was prepared through solid state method. Structure characterization shows Na^＋ is successfully introduced into the LiFePO4 matrix. Scanning electron microscopy shows the particle size mainly ranges in 1-3 μm. X-ray diffraction Rietveld refinement demonstrates lattice distortion with an increased cell volume. As one cathode material, it has a discharge capacity of 150 mAh/g at 0.1 C rate. The material exhibits a capacity of 109 and 107 mAh/g at 5 and 7.5 C respectively. When cycled at 1 and 5 C, the material retains 84% （after 1000 cycles） and 86% （after 350 cycles） of the initial discharge capacity respectively indicating excellent structure stability and cycling performance. Na^＋ doping enhances the electrochemical activity especially the cycle performance effectively.

Quantum Chemistry Study on Local Structure and Properties of Amorphous Fe80P20 Alloy

According to the structure features of Fe80P20, A series of clusters Fe4P were designed and focused on studying the stability of local structure, charge distribution and chemical bond, Using the DFT method, energy and structure of Fe4P clusters were optimized and analyzed. The computational results showed that the energy of cluster 1（2） has the lowest energy, and the possibility of its existence in the Fe80P20 is high. Analyzing the transition states among the clusters, it was found that the clusters in the doublet state are more stable than those in the quartet state. The numbers of the Fe-P bond in the clusters play important roles in the cluster stability and electrons transfer properties, The more numbers of Fe-P bonds in the clusters, the higher the cluster stability, and the weaker the ability of P atom to get electron, The number of Fe atoms, which has bonding interactions with the P atom, is direct proportional to the average 3d orbit population of Fe atom. Basing on the orbital population, average magnetic moments of each Fe atom in the Fe4P clusters were calculated, and they are all smaller than that of single metal Fe atom. This suggests that all Fe4P clusters have soft magnetic property and they are expected to be perfect material for preparing soft magnetic apparatus.

Effects of Zn/P ratio on structures and properties of zinc-iron phosphate glasses

Effects of Zn/P ratio on the structures and properties of glasses with the general composition of （80-x）ZnO-20Fe2O3-xP2O5 （x=40, 45, 50, 55, 60） （molar fraction, %） were investigated. Glass structure was measured by infrared absorption spectrum. Glass density （/9） was measured by the Archimedes method. Coefficients of thermal expansion （a） and characterization temperature were obtained by a dilatometer. Water durability of each glass was estimated from the dissolution rate （DR）in water at 90 ℃ for 24 h. With increasing Zn/P ratio, water durability of zinc-iron phosphate glasses increases dramatically without large increase in the characterization temperature. （80-x）ZnO-20Fe2O3-xP2O5 glasses with 0.3≤Zn/P≤0.5 are suit for low-to-mid temperature sealing application for substrates with a〈8.0× 10^-6℃^-1.