EXFOLIATION AND SODIUM CYCLING BEHAVIOR OF TRANSITION METAL DICHALCOGENIDE NANOSHEETS

摘要

Batteries are under consideration for powering of an increasingly diverse range of applications from stationary solar/wind energy farms to flexible and wearable devices like Google Glass and Microchips.1 Among non-Li metal ion based batteries, Na, Mg, Al and K-ion batteries are at the forefront. Na-ion batteries have drawn increasing attention because in contrast to lithium (Li), Na resources are practically inexhaustible and evenly distributed around the world. Also, since Na and Li are stacked in the periodic table, it is easily assumed that battery anodes for Li can be directly utilized for Na batteries. This assumption has been debunked; Na and other metal-ions of technological relevance are much larger than Li-ion and electrode design must be altered to accommodate: (a) their slow diffusion kinetics in the bulk, and (b) fatigue associated with large volume changes upon insertion/extraction that causes capacity degradation.