Superior cycle stability of graphene nanosheets prepared by freeze-drying process as anodes for lithium-ion batteries

• Published in: Journal of power sources Vol. 254; pp. 198 - 203
• Main Authors: Cai, Dandan, Wang, Suqing, Ding, Liangxin, Lian, Peichao, Zhang, Shanqing, Peng, Feng, Wang, Haihui
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.05.2014; Elsevier
• Subjects: Anode materials; Applied sciences; Current density; Cycle stability; Density; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electron microscopes; Exact sciences and technology; Freeze-drying; Graphene; Graphene nanosheets; Lithium; Lithium-ion batteries; Materials; Nanostructure; Specific surface; Stability; Lithium-ion batteries; Graphene nanosheets; Cycle stability; Freeze-drying; Anode materials; Lithium ion batteries; Freeze drying; Stability; Nanosheet; Anode; Secondary cell; Nanostructure; Electrode material; Graphene; Preparation
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.12.136

Graphene nanosheets are synthesized by a novel facile method involving freeze-drying technology and thermal reduction. The microstructure and morphologies are characterized by X-ray diffraction, Brunauer–Emmett–Teller measurements, Fourier transform infrared spectroscopy, and high resolution transmission electron microscope. The results indicate that graphene nanosheets with high specific surface area (358.3 m2 g−1) and increased interlayer distance (0.385 nm) are successfully obtained through the freeze-drying process. The electrochemical performances are evaluated by using coin-type cells versus lithium. A high initial reversible capacity of 1132.9 mAh g−1 is obtained at a current density of 100 mA g−1. More importantly, even after 300 cycles at a high current density of 1000 mA g−1, a stable specific capacity of 556.9 mAh g−1 can be achieved, suggesting the graphene nanosheets exhibit superior cycle stability. The fascinating electrochemical performance could be ascribed to the high specific surface area and the increased layer distance between the graphene nanosheets. •A novel facile synthesis of graphene nanosheets involving freeze-drying technology.•The as-prepared materials exhibit superior cycle stability and rate performance.•The freeze-drying helps to enlarge the interlayer distance and specific surface area.