(Invited) Electrocatalysts for Lithium-Oxygen and Li-Sulfur Batteries

Abstract

Electrocatalysis plays a critical role in metal-oxygen and metal-sulfur batteries. Rational catalyst design for nonaqueous oxygen evolution reaction (OER) in Li-O2 batteries and polysulfide reduction reaction in Li-S batteries is required to further improve the battery performances. In this presentation, we will discuss the catalyst effects and design strategies to improve the electrode kinetics and reversibility of Li-O2 and Li-S batteries. We will discuss promoting the fraction of the high-surface-energy facet of the catalyst is an effective approach to increase the Li-O2 OER activity. We designed and synthesized a series of chromium oxide (Cr2O3) with varying fractions of high-energy facet by inhibiting the growth of the low-energy facet, i.e. (012) of Cr2O3. We will discuss the correlation between the Li-O2 OER activity and the fraction of high-energy facet. Catalyst design consideration for polysulfide reduction to lithium sulfide will also be discussed. We will combine electrochemical characterizations and spectroscopic techniques to provide insights into the catalytic processes in these battery systems. Acknowledgement: This work was supported by two grants from the Research Grants Council (RGC) of the Hong Kong Special Administrative Region, China, under T23-601/17-R and NSFC/RGC Joint Research Scheme 2018/19 Project No. N_CUHK435/18.