石墨烯的制备及其作为锂离子电池负极的性能

Preparation and characterization of graphene as negative electrode of lithium ion battery

为更好地研究石墨烯作为锂离子电池负极的性能,采用改进的Hummers方法,以天然鳞片石墨为原料,设计正交实验。通过改变插层剂的组成、氧化剂的比例、氧化反应时间、温度等反应参数来优化石墨烯的制备工艺,并通过XRD、FTIR、Raman和电池充放电测试等方法对产物的组成、结构和电化学性能进行表征。结果表明:石墨经氧化后形成了含有CO、—COOH和C—O—C等官能团的石墨层间化合物;Raman光谱中rGO的积分强度比(ID/IG)比GO明显降低;在74.4 mA/g约为0.1 C的电流密度下进行电池充放电,rGO负极的首次放电容量为700 mAh/g,30次循环电池放电性能稳定,可逆容量为350 mAh/g。

Aimed at in-depth investigation into the performances of grapheme used as the negative electrode of lithium ion battery, this paper features the graphite oxides （GO）, prepared by employing modified Hummers method, using the natural flake graphite as raw materials, and designing the orthogonal experiments. The paper highlights the optimization of the preparation technique of graphene by changing the composition of intercalation, the proportion of oxidant, the oxidation reaction time and temperature, et al. , and the characterization of the composition, structure and electrochemical performance of GO and reduced GO by the methods of XRD, FTIR, Raman and battery charge/discharge test. Results show that, subjected to oxidation, graphite transforms into graphite-intercalation-compound containing different functional groups, such as C = O, -COOH and C-O-C, et ah. Raman spectra of rGO （ID/IG） ratio shows a significantly lower integral intensity than GO. At the current density of 74.4 mA/g 0.1 C, rGO, battery charges and discharges behaves in such a way that negative electrode features the first-cycle discharge capacity of 700 mAh/g, the stable discharge performance after the following 30 cycles, and the reversible capacity of 350 mAh/g.