부산대학교 도서관

Lithium sulfide (Li 2 S) is a promising cathode material with a high theoretical capacity (1166 mA h g−1) that can be paired with nonlithium-metal anodes, which can eliminate the safety issue related with lithium anode. Nevertheless, its poor electronic conductivity and low Li ion diffusion lead to the high activation barrier of Li 2 S and sluggish kinetic conversion to polysulfides, hindering its commercialization. Herein, Li 2 S particles coated by Co nanomaterial-decorated porous carbon shells (Li 2 S/Co@C) are catalytically synthesized in-situ as the Li 2 S-Co heterostructures to enhance Li 2 S reactivity and its kinetic conversion via a carbothermic reduction. This Li 2 S/Co@C shows an ultra-low activation potential of 3.12 V, smaller by 0.74 V compared with commercial Li 2 S. Significantly, it presents an initial reversible capacity of 1006 mA h g−1 and maintains a high reversible capacity of 335 mA h g−1 at 0.1 C (1 C = 1166 mA g−1) after 500 cycles. An outstanding rate capacity is also achieved with a reversible capacity of 148 mA h g−1 at 3 C. More importantly, in-/ex - situ characterizations underscore that Co nanomaterials can serve as an Li 2 S-Co heterostructure catalyst to enhance the reactivity of Li 2 S, lithium polysulfides, and sulfur, thereby achieving high performance in Li-S batteries. [ABSTRACT FROM AUTHOR]