In Situ Grown 1T′-MoTe2 Nanosheets on Carbon Nanotubes as an Efficient Electrocatalyst and Lithium Regulator for Stable Lithium-Sulfur Full Cells

Lithium-sulfur batteries offer the advantage of high energy density at a low cost, but their viability is hindered by the polysulfide shuttle effect, sluggish reaction kinetics, and dendritic Li growth. To address these persistent challenges in a unified manner, a dual-function, flexible, free-standing framework by coupling catalytic and lithiophilic 1T '-MoTe2 nanosheets with conductive carbon nanotubes (MoTe2-CNT), which serve as a host for both a sulfur cathode (S/MoTe2-CNT) and a lithium-metal anode (MoTe2-CNT/Li) is presented here. MoTe2-CNT not only guides a uniform growth of lithium within the framework, but also forms a thin, unique sulfide-rich solid-electrolyte interphase (SEI) composed of lithium thiotellurate on the Li surface when paired with a sulfur cathode. This SEI stabilizes Li deposition, suppresses electrolyte decomposition, and prevents Li loss, thereby prolonging cycle life. Full coin cells with a very low negative to positive electrode capacity ratio of approximate to 2.5 and a high areal capacity of 7.6 mA h cm(-2) display 75% capacity retention after 500 cycles. The pouch cells fabricated with MoTe2-CNT deliver a high capacity of 1533 mA h g(-1) and energy density of 319 Wh kg(-1) at a low electrolyte-to-capacity ratio of approximate to 2.9 mu L [mA h](-1) and a low electrolyte-to-sulfur ratio of 4.5 mu L mg(-1).

Automated summary

This study presents a dual-function, flexible, free-standing framework that tackles the challenges faced by lithium-sulfur batteries by coupling catalytic and lithiophilic MoTe2 nanosheets with conductive carbon nanotubes. The SEI formed by MoTe2-CNT stabilizes Li deposition and extends battery cycle life.