### 石墨烯材料的储锂行为及其潜在应用

1. a 中国科学院金属研究所 沈阳材料科学国家(联合)实验室 沈阳 110016;
b 南非科学及工业研究院 比勒陀利亚 南非 0001
• 投稿日期:2013-09-19 发布日期:2013-12-17
• 通讯作者: 李峰，E-mail：fli@imr.ac.cn E-mail:fli@imr.ac.cn
• 基金资助:

项目受国家自然科学基金（Nos. 51172242，51221264）和中国科学院战略性先导科技专项（No. XDA01020304）资助.

### Lithium Storage Characteristics and Possible Applications of Graphene Materials

Wen Leia, Liu Chengminga, Song Renshenga, Luo Hongzeb, Shi Yinga, Li Fenga, Cheng Huiminga

1. a Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016;
b Council for Scientific and Industrial Research, Pretoria, South Africa 0001
• Received:2013-09-19 Published:2013-12-17
• Supported by:

Project supported by the National Natural Science Foundation of China (Nos. 51172242, 51221264) and "Strategic Priority Research Program" of the Chinese Academy of Sciences (No. XDA01020304).

Graphene materials are materials with a flat mono/few layer of carbon atoms tightly packed to a two-dimensional honeycomb lattice. Graphene materials are expected to be applied in lithium ion batteries due to their unique structural, mechanical and electrical properties. As an anode material, the charge/discharge characteristics of graphene materials is similar to those of low-temperature soft carbon materials, such as high capacity, low initial efficiency and large voltage hysteresis. Although attractive results have been achieved for graphene as anode materials for LIBs, detailed lithium storage mechanisms are still not clear. The effects of the following several structural parameters including disorder degree, surface area, micropores, interlayer spacing, C/O ratio and layer number on the lithium storage properties are discussed. Thermally reduced graphene materials with a highly disordered structure and high surface area has exceptionally high reversible capacity. Micropores in graphene materials have a great impact on their electrochemical performance. Although these micropores can provide additional sites for increased reversible lithium storage, it can also results in severe capacity fading and voltage hysteresis. Oxygen functional groups and larger interlayer spacing may provide higher reversible capacity of graphene, but the micropores and defect-based reversible storage may be the main contribution. Effect of layer number on lithium storage mechanisms of graphene and the conclusion are still in debate. Graphene with rich oxygen functional groups is a promising cathode material with high capacity and rate performance for lithium storage. High specific capacity of graphene cathode is mainly ascribed to lithiation reaction of oxygen functional groups, such as epoxide and carbonyl groups. Lithiation of oxygen functional groups still requires further study for a full understanding. Based on the lithium storage characteristics of graphene anode and cathode, lithium ion capacitors with high energy density and graphene composite cathode materials for lithium ion batteries may be designed and developed in the future. Graphene based lithium ion capacitors facilitate the reversible lithium storage, which significantly improves the energy density of lithium ion capacitors compared to those of conventional systems based on activated carbon. LiFePO4 modified with graphene layers has reached 208 mAh/g in specific capacity. The excess capacity is attributed to the reversible reduction-oxidation reaction between the lithium ions of the electrolyte and the exfoliated graphene flakes.