Researchers at the University of Texas at Austin are proposing a novel approach to suppress the “polysulfide shuttle” in Li-S batteries—a freestanding, three-dimensional graphene/1T MoS2 (3DG/TM) heterostructure with highly efficient electrocatalysis for lithium polysulfides (LiPSs).
Cells with 3DG/TM exhibit outstanding electrochemical performance, with a high reversible discharge capacity of 1181 mAh g-1 and a capacity retention of 96.3% after 200 cycles. An open-access paper on their work is published in the RSC journal Energy & Environmental Science.
The 3DG/TM heterostructure is constructed by a few-layered graphene nanosheets sandwiched by hydrophilic, metallic, few-layered 1T MoS2 nanosheets with abundant active sites.
The metallic 1T MoS2 nanosheets are hydrophilic with rich active sites and high electronic conductivity that is six orders of magnitude higher than that of 2H MoS2.
The conversion process of LiPSs on a graphene surface with 1T MoS2. The 3DG/TM heterostructures work as a highly efficient electrocatalyst for LiPSs conversion. He et al.
The porous 3D structure and the hydrophilic feature of 1T-MoS2 are beneficial for electrolyte penetration and Li-ion transfer, and the high conductivities of both graphene and 1T MoS2 nanosheets facilitate electron transfer.
These attributes lead to a high electrocatalytic efficiency for LiPSs due to excellent ion/electron transfer and sufficient electrocatalytic active sites.
Jiarui He, Gregory Hartmann, Myungsuk Lee, Gyeong S. Hwang, Yuanfu Chen and Arumugam Manthiram (2018) “Freestanding 1T MoS2/Graphene Heterostructure as a Highly Efficient Electrocatalyst for Lithium Polysulfides in Li-S Batteries” Energy Environ. Sci. doi: 10.1039/C8EE03252A