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Cadmium oxides (CdO), an important semiconductor material, have many superior properties when used as a cathode material for nickel-cadmium batteries. Here, the coating and the doped co-modified LiNi 0.8 Co 0.15 Al 0.05 O 2 cathode are constructed by a continuous wet chemical process and a high-temperature sintering process, wherein the Cd2+ are uniformly doped in a gradient form and the CdO protective layer is distributed on the outer surface of secondary particles. The Cd-modified NCA material has more stable interfacial and crystal lattice structure, thereby inhibiting harmful phase transitions and side-reactions. Accordingly, the modified sample has excellent electrochemical performance and maintaining a complete spherical morphology during long cycling compared to the pristine sample. In addition, as a pillar ion, cadmium increases the plate spacing and lithium-ion diffusion kinetics. The electrochemical results show that the capacity retention of the modified sample Cd-2000 reached 96.5% and 90.6% after 100 cycles and 200 cycles respectively at 1 C. At the high current rate of 8 C, the initial capacity and retention (100 cycles, 3.0–4.3 V) reach 166.2 mAh g−1 and 95.2%, respectively. Besides, the results of electrochemical impedance spectroscopy (EIS) reveal that CdO modification could decrease the resistance of the cell polarization and impedance increment upon cycling. Image 1 • The Cd-modified NCA cathode is prepared by simple wet chemical precipitation-calcination techniques. • The modification of LiNi 0.8 Co 0.15 Al 0.05 O 2 cathode was achieved by the synergistic effect of CdO coating and Cd ion doping. • After modification, the interface and crystal structure stability is improved. • The Cd-modified cathode material achieves excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Abstract: Curie temperature, initial permeability and resistivity of MnZn ferrites with Fe-poor composition (less than 50mol% of Fe2O3) are studied. The experience formula of Curie temperature for MnZn ferrites with Fe-rich composition is modified to calculate the Curie temperature of Fe-poor MnZn ferrites. Tri-segment frequency dispersion model, which consists of domain wall motion, magnetization rotation and gyro-magnetic spin rotation, is used to simulate the permeability spectra of ferrites. The permeability of Fe-poor MnZn ferrites compares with that of Fe-rich MnZn ferrites in low frequency region, and it is still high enough to compare with that of NiZn ferrites in high frequency region. The resistivity of Fe-poor MnZn ferrites is about 103 Ωm, much higher than that of Fe-rich MnZn ferrites. [Copyright &y& Elsevier]

LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) is regarded as one of the promising Li-ion battery cathode materials due to the high capacity and low cost, but the poor cyclic and rate performances hinder its widespread application. In our research, La and Al co-modified NCM811 is successfully prepared by a simple method. XRD and XPS confirm that La and Al can not only dope into the NCM811 bulk, but also form the La 2 Li 0.5 Al 0.5 O 4 coating layer on the surface. The La 2 Li 0.5 Al 0.5 O 4 coated and La-and-Al-doped NCM811 exhibits an excellent capacity retention of 97.2% at 1C in the voltage range of 3.0–4.4 V after 100 cycles, 18.5% higher than that of the pristine. As for rate performance, it exhibits a retention of 95.1% in capacity at 5C after 80 cycles from 3.0 V to 4.4 V, 6.4% higher than that of the pristine. The enhanced high-voltage electrochemical performances are mainly ascribed to the facts that the La and Al strengthen the bulk structure by co-doping and the formed La 2 Li 0.5 Al 0.5 O 4 coating layer, as the high-Tc superconducting oxides, not only promotes the diffusion of Li+ but also protect the cathodes from eroding by with the electrolyte. Meanwhile, the residual lithium is reduced by the formation of La 2 Li 0.5 Al 0.5 O 4. The enhanced electrochemical performance shows that the modification of La 2 Li 0.5 Al 0.5 O 4 coating and La–Al co-doping is a competitive method for industrial production of NCM811 material. • The La–Al co-doping and La 2 Li 0.5 Al 0.5 O 4 coating NCM811 cathode material was prepared by a simple method. • The La and Al were doped in the host material uniformly. • La 2 Li 0.5 Al 0.5 O 4 coating protects the active material from electrolyte eroding. • The co-modification method contributes to the superior electrochemical performances of NCM811. [ABSTRACT FROM AUTHOR]