Kyung Yoon Chung

Abstract:

The demand for energy storage systems (ESS) has increased tremendously in the last decade due to their use in a variety of applications ranging from mid- to large-scale. The most important factors in the development of ESS include high-performance and cost-effective systems. At present, lithium-ion batteries (LIBs) are being used as storage devices but their application is limited to small- to medium-scale. The main reasons to not use LIBs at large-scale are high production cost and limited lithium resources. While searching for alternatives, sodium-ion batteries (SIBs) have emerged as a potential candidate for the use of ESS, which is considered cost-effective and also share similar electrochemical principle to LIBs. However, high-performance cathode and anode materials are urgently required for the commercialization of SIBs.
In the search of high-performance electrode materials, we have prepared several cathode and anode materials for SIBs. I will briefly discuss the preparation and electrochemical properties of the high-performance cathode materials, which include FeF₃.0.5H₂O and olivine-type NaFePO₄, and also discuss the investigated reaction mechanism. The nanocomposite of FeF₃.0.5H₂O and reduced graphene oxide has shown high sodium storage performance where it delivers a capacity of 266 mAh g^-1 while NaFePO₄ has shown excellent cyclability with a capacity retention of 94% after 100 cycles. Further, alloying-based SnF₂ anode material was prepared and the electrochemical properties, as well as reaction mechanism, were systematically investigated. The nanocomposite of SnF₂ and acetylene black has shown promising electrochemical performance where it delivers a high capacity of 563 mAh g^-1. In-situ XRD and synchrotron-based X-ray absorption spectroscopy (XAS) were used to investigate the reaction mechanism of the above-mentioned materials. The details of the investigated reaction mechanism will be discussed in my presentation.