Electrode/Electrolyte Interfaces in High-Voltage Aqueous Alkali-Ion Batteries

点击翻译按钮获取中文摘要

Energy storage at an affordable cost has emerged as one of the challenging issues for the energy sector. It is critical for a wide range of applications ranging from electric vehicles to grid storage of renewable energies. Batteries that use an aqueous (water-based) electrolyte have the potential to be more durable and less prone to thermal runaways than current lithium batteries that use an organic solvent. Many of these energy storage applications require high energy density with safe, thermal control of the system. The aqueous electrolyte can solve this problem and also be beneficial for energy storage due to its low cost and high power. However, current aqueous battery technology has an insufficiently low energy density and a narrower voltage output compared to lithium-ion batteries using organic electrolyte. The aim of this research project is to expand the voltage operating window of aqueous batteries. This research will use model thin film systems and combine a suite of advanced in-situ synchrotron X-ray scattering and spectroscopy methods to study the electrode/electrolyte interfaces, which is posited to be the key to enable high voltage in these systems. In addition to advancement in science, the project also promotes the participation of undergraduate students in research through Oregon State University’s Johnson Scholarship and conducts STEM outreach through the OSU Summer Experience in Science & Engineering for Youth Program involving pre-college students in middle school and high school.Aqueous alkali-ion batteries (AAIBs) are promising candidates for large-scale electrochemical energy storage in terms of cost, safety, and power capability. Compared to lithium-ion batteries using organic electrolyte, the main drawback of AAIBs is the limited 1.23 voltage window, beyond which the water splitting reaction happens and consequently hydrogen and/or oxygen gases are produced. Although some successful cases have demonstrated that using water-in-salt electrolyte can obtain high-voltage (more than 3 V) for some aqueous lithium-ion chemistries, such knowledge has not been transformed to other alkali ion chemistries such as sodium or potassium-ion. The goal of this project is to use well-defined thin film systems of aqueous lithium-ion batteries and in-situ synchrotron X-ray techniques to study the formation, structure and composition of solid-electrolyte interphases at the anode and cathode. Such knowledge can be used to design aqueous batteries with high-voltage and long cycling life.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.