1 research outputs found
Endothermic Dehydrogenation-Driven Preventive Magnesiation of SiO for High-Performance Lithium Storage Materials
Silicon monoxide (SiO)-based materials have gained much
attention
as high-capacity lithium storage materials based on their high capacity
and stable capacity retention. However, low initial Coulombic efficiency
associated with the irreversible electrochemical reaction of the amorphous
SiO2 phase in SiO inhibits the wide usage of SiO-based
anode materials for lithium-ion batteries. Magnesiation of SiO is
one of the most promising solutions to improve the initial efficiency
of SiO-based anode materials. Herein, we demonstrate that endothermic
dehydrogenation-driven magnesiation of SiO employing MgH2 enhanced the initial Coulombic efficiency of 89.5% with much improved
long-term cycle performance over 300 cycles compared to the homologue
prepared by magnesiation of SiO with Mg and pristine SiO. High-resolution
transmission electron microscopy with thermogravimetry–differential
scanning calorimetry revealed that the endothermic dehydrogenation
of MgH2 suppressed the sudden temperature rise during magnesiation
of SiO, thereby inhibiting the coarsening of the active Si phase in
the resulting Si/Mg2SiO4 nanocomposite