Understanding Charge Storage Mechanisms for Amorphous MoSnSe_(1.5)S_(1.5) Nanoflowers in Alkali-Ion Batteries

摘要

Transition metal sulfides/selenides have been reported as promisingmaterials for alkali-ion batteries owing to their high pseudocapacitive effectsand large capacities. However, these materials undergo large volumeexpansion, which results in poor cycling retention. Hence, in this study, anamorphous bimetallic chalcogenide, MoSnSe_(1.5)S_(1.5) (MSSS), is synthesized tomitigate the volume expansion. By introducing an amorphous structure,MSSS can reach high capacities of 805 mAh g~(-1) in Li-ion batteries (LIBs) and526 mAh g~(-1) in Na-ion batteries (NIBs) at a current density of 0.1 A g~(-1).Moreover, amorphous MSSS can tolerate a high current density of 20 A g~(-1)and possess high percentages of capacitance contributions in both LIBs andNIBs. To explore fundamentals, in situ/operando measurements, such asX-ray absorption spectroscopy, transmission X-ray microscopy, andtransmission electron microscopy, are utilized to investigate real-timephenomena and consequently establish the reaction mechanisms foramorphous MSSS electrodes in alkali-ion batteries.