In:
Inorganic Chemistry Frontiers, Royal Society of Chemistry (RSC), Vol. 8, No. 19 ( 2021), p. 4395-4406
Kurzfassung:
Engineering of graphite@Si/carbon composites is considered as an effective strategy to surmount the shortcomings of the low conductivity and large volume expansion of bare Si anode materials for lithium-ion batteries. Nevertheless, their applications in high-performance electric vehicles are still challenging owing to their limited accessible capacity. Herein, SiO 2 as an active additive was introduced to improve the capacity of graphite@Si/carbon composites. Two different composites, graphite@Si sequentially embedded in SiO 2 and carbon layers (G@Si/SiO 2 layer/C) and encapsulated in a carbon conformally coated tiny SiO 2 nanoparticle matrix (G@Si/SiO 2 NPs/C), were well-designed. Both the Si/C composites exhibit a longer cycle life than the graphite@Si/C due to the unique double protective sheath of inert components (Li 2 O and Li 4 SiO 4 ) and carbon. The former was formed during the first lithium insertion of SiO 2 . Specifically, the G@Si/SiO 2 NPs/C shows a high specific capacity (607 mA h g −1 ), exceptional cycling stability (92% retention after 800 cycles at a 0.5 A g −1 ) and promising rate capability. The remarkable performances benefit from the porous three-dimensional network structure constructed by an amorphous carbon matrix shell and a graphite core, which well disperse and support Si and SiO 2 , thus improving their electrochemical activity, alleviating the volume change and increasing the Li-ion diffusion effectively.
Materialart:
Online-Ressource
ISSN:
2052-1553
Sprache:
Englisch
Verlag:
Royal Society of Chemistry (RSC)
Publikationsdatum:
2021
