Mechanochemical Synthesis of γ-Graphyne with Enhanced Lithium Storage Performance.

γ-Graphyne is a new nanostructured carbon material with large theoretical Li+ storage due to its unique large conjugate rings, which makes it a potential anode for high-capacity lithium-ion batteries (LIBs). In this work, γ-graphyne-based high-capacity LIBs are demonstrated experimentally. γ-Graphyne is synthesized through mechanochemical and calcination processes by using CaC2 and C6 Br6 . Brunauer-Emmett-Teller, atomic force microscopy, X-ray photoelectron spectroscopy, solid-state 13 C NMR and Raman spectra are conducted to confirm its morphology and chemical structure. The sample presents 2D mesoporous structure and is exactly composed of sp and sp2 -hybridized carbon atoms as the γ-graphyne structure. The electrode shows high Li+ storage (1104.5 mAh g-1 at 100 mA g-1 ) and rate capability (435.1 mAh g-1 at 5 A g-1 ). The capacity retention can be up to 948.6 (200 mA g-1 for 350 cycles) and 730.4 mAh g-1 (1 A g-1 for 600 cycles), respectively. These excellent electrochemical performances are ascribed to the mesoporous architecture, large conjugate rings, enlarged interplanar distance, and high structural integrity for fast Li+ diffusion and improved cycling stability in γ-graphyne. This work provides an environmentally benign and cost-effective mechanochemical method to synthesize γ-graphyne and demonstrates its superior Li+ storage experimentally.