Abstract
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Presently, lithium-ion batteries (LIBs) are the most promising
commercialized electrochemical energy storage systems.
Unfortunately, the limited resource of Li results in increasing
cost for its scalable application and a general consciousness of
the need to find new type of energy storage technologies. Very
recently, substantial effort has been invested to sodium-ion batteries
(SIBs) due to their effectively unlimited nature of sodium
resources. Furthermore, the potential of Li/Li+ is 0.3 V lower
than that of Na/Na+, which makes it more effective to limit the
electrolyte degradation on the outer surface of the electrode.[1]
Nevertheless, one major obstacle for the commercial application
of SIBs is the larger ionic radius of Na+ (0.98 Å) which is
0.29 Å larger than that of Li+, resulting in easier structural degradation
for the Na+ host materials.[2,3] As anode materials for
SIBs, the traditional carbon-based materials like hard carbon[4]
and porous carbon,[5,6] tin (Sn),[7] and antimony (Sb)[8] show
poor cycle performance due to their large volume expansion
caused by Na+ insertion.