The Electrode Properties of Mg1.9Al0.1Ni0.8Co0.1Mn0.1 Alloy by Mechanical Grinding with Ni Powders

A modified magnesium alloy of composition Mg1.9Al0.1Ni0.8Co0.1Mn0.1 was prepared by mechanical grinding with Ni powder for periods up to 120 h. The resulting structures of the Mg1.9Al0.1Ni0.8Co0.1Mn0.1 alloys were found to be amorphous. The electrodes of the modified Mg1.9Al0.1Ni0.8Co0.1Mn0.1 alloys had large discharge capacities. At a discharge current rate of 50 mA/g, the capacity was 630 mAh/g after 50 h of mechanical grinding and 510 mAh/g after 120 h of mechanical grinding

Anomalous magnetization peak effect in spiral-grown Bi2Sr2CaCu2Oy crystals

Magnetic hysteresis loops were measured on spiral-grown Bi2Sr2CaCu2Oy (Bi-2212) crystals. An anomalous peak effect at a magnetic field of 1000–2000 Oe was observed both in high-Tc (86 K) and oxygen underdoped (Tc=76 K) spiral-grown crystals between 20 and 40 K. The peak effect was observed to be stronger than that induced by oxygen vacancies, defect dislocation networks reported in Bi-2212 crystals. Further, the anomalous peak almost completely disappeared after removing growth spiral patterns from the crystal surface. Edge barriers associated with the growth spirals are suggested to be responsible for the strong peak effect for the spiral-grown Bi-2212 crystals and not oxygen vacancies or screw dislocations

Characterization of LiMxFe1–xPO4 (M = Mg, Zr, Ti) Cathode Materials Prepared by the Sol-Gel Method

A series of LiMxFe12xPO4 (M 5 Mg,Zr,Ti) phosphates were synthesized via a sol-gel method. Transmission electron microscopy observations show that LiMxFe12xPO4 particles consist of nanosize crystals, ranging from 40 to 150 nm. High-resolution TEM analysis reveals that a layer of amorphous carbon was coated on the surface of the LiMxFe12xPO4 particles, which substantially increases the electronic conductivity of LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 powders are phase pure. Near full capacity ~170 mAh/g! was achieved at the C/8 rate at room temperature for LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 electrodes demonstrated better electrochemical performance than that of undoped LiFePO4 at high rate