Facile Synthesis of Multi-channel Surface Modified Amorphous Iron Oxide Nanospheres as a High-performance Anode Material for Lithium-ion Batteries

The application of iron oxide as anode of lithium-ion batteries is hindered by its poor cycle stability, low rate performance and large voltage hysteresis. To address these problems, multi-channel surface modified amorphous Fe2O3 nanospheres were synthesized by using a facile hydrothermal method, which exhibited outstanding electrochemical performances. According to crystalline state and microstructure, it was found that surface structure of the amorphous Fe2O3 nanospheres can be controlled by adjusting the reaction time, due to the synergistic effect of ripening and hydrogen ion etching. Owing to the isotropic nature and the absence of grain boundaries, the amorphous Fe2O3 nanospheres could withstand high strains during the intercalation of lithium ions. Meanwhile, the multi-channel surface structure can not only increase the contact area between Fe2O3 nanospheres and electrolyte, but also reserve space for volume expansion after lithium storage, thereby effectively alleviating the volume change during the intercalation-deintercalation of lithium ions. As confirmed by the Galvanostatic intermittent titration analysis results, the amorphous Fe2O3 electrode had higher Li+ diffusion coefficient than the crystalline counterpart. As a result, the multi-channel surface modified amorphous Fe2O3 electrode exhibited higher specific capacity, more stable cycle performance and narrower voltage hysteresis. It is believed that amorphous metal oxides have great potential as high-performance anode of next-generation lithium-ion batteries.

High-Efficiency Electrocatalyst Phthalocyanine in Li/SOCl2 Batteries: From Experimental to Theoretical Investigation

Li/SOCl2 batteries, which are used in various fields due to theirs easy-carry and brilliant electrochemical properties, have attracted much research. However, the existence of the voltage hysteresis has limited further practical application of this tiny device. Herein, three series of nineteen kinds of metal phthalocyanine electrocatalysts with excellent electronic conductivity were synthesized to improve Li/SOCl2 battery performance. The structure of the catalysts was verified by infrared spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, and elemental analysis,. and these materials were used to develop the discharge time, output voltage, and discharge capacity of the Li/SOCl2 battery. With the addition of the phthalocyanine, the discharge time of the Li/SOCl2 battery lengthens by approximately 20%, and the voltage can be increased by 0.02~0.20 V. In addition, the actual battery capacity can also be raised by 20~50 %. Density functional theory was used to calculate the relationship between the metal center and catalytic activity and the results are in good agreement with the experimental which implies the electron density of the center metal is the key point in the electrocatalyst reaction.