Li(Al_1–zZn_z) alloys as anode materials for rechargeable Li-ion batteries

The cycling behavior of anode materials based on alloys from the Li(Al_1–zZn_z) continuous solid solution has been studied. The performance of the most promising composition Li(Al_0.8Zn_0.2) was tested in half-cells against metallic Li with three different electrolytes and in full Li-ion cells against a V₂O₅cathode. The underlying structure evolution during cycling and the most relevant fatigue mechanisms are elucidated by x-ray diffraction, nuclear magnetic resonance, and x-ray photoelectron spectroscopy, and reveal a loss of mobile Li due to the ongoing formation of solid electrolyte interfaces. An enhanced stability for Li(Al_1–zZn_z) electrodes withz˜0.2 results from a peculiar microstructure due to the decomposition of Al and Zn in the Li-poor state and their intermixing in the Li-rich state.