In-situ Lithiated SiO2 as Lithium-Free Anode for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are attractive owing to their high energy density and cost-effectiveness. However, the practical application of Li-S batteries is hindered by uncontrollable lithium dendrite growth and severe polysulfide shuttling during cycling. Here, we fabricated 100 nm thin SiO2 decorated on carbon cloth (SiO2@CC). It is observed that in-situ lithiation of SiO2 forms a highly lithiophilic LixSiOy layer over SiO2 which further acts as an efficient host for dendrite-free lithium metal deposition. So lithiated SiO2@CC shows high affinity for homogenous growth of Li while the carbon fibers control the volume change during the deposition/stripping process. Hence, the synergistic effect of LixSiOy layer and carbon cloth (CC) effectively suppresses dendritic Li growth. As a result, the symmetric cell exhibits an ultra-stable cycling performance over 1000 h with a low overpotential of <25 mV even at a high current density of 1 mA cm(-2). Further, the lithiated SiO2@CC is used as a lithium metal-free anode (also a flexible electrode) for Li-S battery, which exhibits a stable capacity of 800 mAh g(-1) over 500 cycles due to its unique structural properties. This work offers new insights and paves the way for developing dendrite-free, high-performance Li-S battery technology.

Automated summary

In this study, a highly lithophilic LixSiOy layer was successfully formed on carbon cloth (CC) through lithiation of 100 nm thin SiO2, which effectively suppressed the growth of lithium dendrites. The symmetric cell exhibited ultra-stable cycling performance over 1000 hours even at a high current density, and the lithiated SiO2@CC used as a lithium metal-free anode showed stable capacity over 500 cycles. This work provides new insights and paves the way for developing dendrite-free, high-performance Li-S battery technology.