Decoupling Electrolyte and Electrode Reactions Using in-Operando Electrochemical X-Ray Powder Diffraction

摘要

Lithium-ion batteries are the dominant energy storage technology - steady and significant progress toward lower costs, better safety, and better performance is being realized by an improved understanding and control of new materials and system engineering. Various novel materials for lithium and lithium-ion battery electrodes are emerging, many of which depend on alkali-metal alloys. Among them, Aluminum electrodes offer the potential for high lithium-ion capacities at low costs, for example, capacities of 2000 mAh/g (six times higher than graphite, the current commercial standard) can be accessed at moderate temperatures (above 40°C), and recent studies show that Aluminum foil electrodes can act as both the active material and current collector. Nevertheless, challenges with capacity fade, electrolyte breakdown, slow diffusion and nucleation barriers still exist and alkali-metal electrochemical reactivity is not fully understood. Elevated temperature operation can be used to overcome nucleation barriers and slow diffusion, but at the cost of increased rates of liquid electrolyte breakdown. Here, we combine controlled temperature electrochemical lithiation and delithiation with x-ray powder diffraction for in-situ studies of electrode and electrolyte reactions to shed light on these problems.