Search

This paper describes a new, high‐performance, Pb‐based nanocomposite anode material for lithium‐ion batteries. A unique nanocomposite structure of Pb@PbO core‐shell nanoparticles in a carbon matrix is obtained by using a simple high‐energy ball milling method using the low‐cost starting materials PbO and carbon black. Electrochemical performance tests show its excellent reversible capacity (≈600 mAh g−1) and cycle stability (92% retention at 100th cycle), which are one of the best values reported for Pb‐based anodes in the literature. Synchrotron X‐ray diffraction and absorption techniques revealed the detailed lithium storage mechanism that can be highlighted with the unexpectedly wide reversible Pb redox range (between Pb2+ and Pb4−) and the evolution of Zintl‐type LiyPb structures during the electrochemical lithium reaction. The results provide new insights into the lithium storage mechanism of these Pb‐based materials and their potential as low‐cost, high‐performance anodes. [ABSTRACT FROM AUTHOR]

The thermal instability of the cathode materials in lithium-ion batteries is an important safety issue, requiring the incorporation of several approaches to prevent thermal runaway and combustion. Systematic studies, using combined well-defined in situ techniques, are crucial to obtaining in-depth understanding of the structural origin of this thermal instability in overcharged cathode materials. Here time-resolved X-ray diffraction, X-ray absorption, mass spectroscopy, and high-resolution transmission electron microscopy during heating are combined to detail the structural changes in overcharged Li xNi0.8Co0.15Al0.05O2 and Li xNi1/3Co1/3Mn1/3O2 cathode materials. By employing these several techniques in concert, various aspects of the structural changes are investigated in these two materials at an overcharged state; these include differences in phase-distribution after overcharge, phase nucleation and propagation during heating, the preferred atomic sites and migration paths of Ni, Co, and Mn, and their individual contributions to thermal stability, together with measuring the oxygen release that accompanies these structural changes. These results provide valuable guidance for developing new cathode materials with improved safety characteristics. [ABSTRACT FROM AUTHOR]