Branched Graphene Nanocapsules for Anode Material of Lithium-Ion Batteries

Abstract

The promising complex structures of graphene nanocapsules with in-situ formed graphene sheets (GC-Gs) have been generated by partially peeling the multiwalled graphene capsules (MWGCs) with a small size of ca. 15 nm. The abundant edges and defects on the in-situ induced graphene sheets and capsule walls largely favored the lithiation/de-lithiation reaction and resulted in a high Li-ion storage level. Since the surface area loss of GC-Gs during stacking and aggregation is generally avoided due to the branched structures and the active doping atoms (N, S) can be intercalated into the carbon lattices during sample preparation, the unique GC-Gs possess an excellent reversible capacity of 1373 mAh g −1 at 0.5 A g −1 as anode material in lithium-ion batteries. This value is more than three times that of the theoretical capacity of state-of-the-art graphite counterpart, and higher than those of most carbon materials reported to date and even the composites of metal, alloys with carbon materials.

Hierarchical Structures Based on Two‐Dimensional Nanomaterials for Rechargeable Lithium Batteries

“…[74] As electrode materials for LIBs, these hollow structured TMOs/TMDs provide outstanding lithium storage performance, compared with their corresponding bulk materials. [84][85][86] As a typical example, N-doped graphene/graphene-tube nanocomposites as Li-O 2 battery cathodes exhibited superior oxygen reduction reactions/oxygen evolution reactions (ORR/OER) activity and improved cathode performance compared to traditional carbon black and Pt/C catalysts. Recently, enormous efforts have been devoted to fabricate complex hollow structured TMOs/TMDs (e.g., yolkshelled TiO 2 sphere, [75] yolk-shelled δ-MnO 2 sphere, [76] multishelled NiS nanobox [77] and yolk-shelled MoSe 2 microsphere [78] ) by advanced synthetic approaches.…”

Critical Insight into the Relentless Progression Toward Graphene and Graphene‐Containing Materials for Lithium‐Ion Battery Anodes

“…For example, branched graphene nanocapsules were proposed as enhanced LIB anode material. [ 94 ] Indeed, despite the steep delithiation voltage and the considerable 1 st cycle irreversible capacity, after 5000 stable cycles, a specifi c delithiation capacity of about 500 mAh g −1 (obtained applying a massive current of 15 A g −1 in the 0.01-3 V range) could be still delivered. Other kinds of graphene also proved their strength upon long term cycling.…”

Binder-free combination of large area reduced graphene oxide nanosheets with Cu foil for lithium ion battery anode

“…During the negatively scanning, 2 reduction peaks were detected at about 0.6 V and 0 V, corresponding to the formation of SEI film [28][29], and the intercalation of Li + within the inter layers and the defects of RGO nanosheets (such as pores, vacancies and edges), respectively [30][31]. Meanwhile, during the positively scanning, 2 oxidation peaks at about 0.3 V and 1.5 V were also observed, which can be ascribed to the extraction of Li + from RGO nanosheets and the defects (such as pores, vacancies and edges), respectively [31][32][33]. Fig.…”