Developing high capacity electrode materials for advanced Li-ion battery
|
강병우 POSTECH Rechargeable Li-ion batteries have become a key enabler for transformational changes in our society by powering advanced portable electronics and deploying electric vehicles and grid-scale applications. To realize this transformation, high energy density Li-ion batteries are an essential requirement. However, the conventional electrode materials such as Ni-rich materials and LiCoO2 has a theoretical limited capacity for achieving high energy density because they can use only transition metal redox reaction for providing available electrons. One of possible ways to overcome this limitation is the use of the oxygen redox reaction for additionally achieving capacity. Li-rich materials (Li1+xTM1-xO2, TM = Transition metals) have recently become one of the most attractive electrode materials because they can deliver much higher capacities (> 250 mAh/g) than conventional layered materials (e.g. LiCoO2) via supplementary oxygen redox reaction in addition to the TM redox reaction. To exploit the potential of the oxygen redox reaction, several approaches have been suggested including applying surface coatings5 for reducing O loss, or replacing 3d-TMs with 4d or 5d-TMs for stabilizing reversibility of the oxygen redox reaction. In this talk, I will discuss how to further increase achievable capacity by using the oxygen redox reaction in Li-rich materials can be controlled and fully exploited to further increase energy density. Especially, I will focus on discussing how cation distribution between the phases of the Li-rich materials can affect the oxygen redox activity and the intrinsic structure stability that will improve voltage retention and capacity retention. |