Thomas E. Conry

TL;DR: In this article, the photovoltaic effect in ferroelectric BiFeO3 thin films was reported and the all-oxide heterostructures with SrRuO3 bottom and tin doped indium oxide top electrodes were characterized by open-circuit voltages ∼08-09V and external quantum efficiencies up to ∼10% when illuminated with the appropriate light.

TL;DR: Micron sized, three dimensional (3D) nanoporous spherical LiFePO4/C synthesized by spray pyrolysis shows excellent cyclability and superior rate capability.

TL;DR: In this paper, spherical nanoporous LiCoPO4/C composite microparticles were synthesized from soluble precursors by spray pyrolysis and achieved a reversible capacity of 123 mAh g−1 at C/10 rate, and showed excellent cycling behavior and rate capability.

TL;DR: In situ X-ray diffraction revealed structural distortions in the transition metal layers of as-synthesized powders with high Al-contents, as well as a structural evolution seen in all materials after cycling.

Abstract: LiNi0.4Co0.15Al0.05Mn0.4O2 was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. In situ X-ray absorption spectroscopy XAS was performed, utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range. 1.0‐4.7 V XAS measurements were performed at different states of charge SOC during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extended X-ray absorption fine structure EXAFS region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni 2+ ,C o 3+ , and Mn 4+ in the as-made material fully discharged, while during charging the Ni 2+ is oxidized to Ni 4+ through an intermediate stage of Ni 3+ ,C o 3+ is oxidized toward Co 4+ , and Mn was found to be electrochemically inactive and remained as Mn 4+ . The EXAFS results during cycling show that the Ni‐O changes the most, followed by Co‐O, and Mn‐O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.