FeOx and Si nano-dots as dual Li-storage centers bonded with graphene for high performance lithium ion batteries.

Abstract

A novel design based on both FeOx and Si nano-dots bonded with graphene (FeOx·Si@GNS) as dual lithium-storage centers is reported. They show high performance as anode materials for Li-ion batteries with a remarkable reversible capacity of 1160 mA h g(-1) at 0.2 A g(-1), fast charging/discharging rate, and long cycling life (e.g., a capacity retention of 81.7% at 2.0 A g(-1) after 600 cycles). The origin of these high performances comes from the key factors of the high theoretical specific capacity of FeOx and Si, the shorter Li-ion diffusion distance of both nano-dot structures, fast electron conductivity, and the strain relaxation due to volume variations of both nano-dots bonded with graphene nanosheets during cycles.