Ling Zheng, Yu Chang, Fan Xiaoming, Liu Shaohong, Yang Juan, Zhang Mengdi, Wang Gang, Xiao Nan, Qiu Jieshan
Carbon Research Laboratory, Liaoning Key Lab for Energy Materials and Chemical Engineering, State Key Lab of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, People's Republic of China.
Nanotechnology. 2015 Sep 18;26(37):374003. doi: 10.1088/0957-4484/26/37/374003. Epub 2015 Aug 28.
A chitosan (CS) based nitrogen doped carbon cryogel with a high specific surface area (SSA) has been directly synthesized via a combined process of freeze-drying and high-temperature carbonization without adding any activation agents. The as-made carbon cryogel demonstrates an SSA up to 1025 m(2) g(-1) and a high nitrogen content of 5.98 wt%, while its counterpart derived from CS powder only shows an SSA of 26 m(2) g(-1). Freeze-drying is a determining factor for the formation of carbon cryogel with a high SSA, where the CS powder with a size of ca. 200 μm is transformed into the sheet-shaped cryogel with a thickness of 5-8 μm. The as-made carbon cryogel keeps the sheet-shaped structure and the abundant pores are formed in situ and decorated inside the sheets during carbonization. The carbon cryogel shows significantly enhanced performance as supercapacitor and lithium ion battery electrodes in terms of capacity and rate capability due to its quasi two-dimensional (2D) structure with reduced thickness. The proposed method may provide a simple approach to configure 2D biomass-derived advanced carbon materials for energy storage devices.
一种具有高比表面积（SSA）的基于壳聚糖（CS）的氮掺杂碳气凝胶，通过冷冻干燥和高温碳化的联合工艺直接合成，无需添加任何活化剂。制备的碳气凝胶的比表面积高达1025 m² g⁻¹，氮含量高达5.98 wt%，而由CS粉末制备的对照物的比表面积仅为26 m² g⁻¹。冷冻干燥是形成具有高比表面积的碳气凝胶的决定性因素，在此过程中，尺寸约为200μm的CS粉末转变为厚度为5 - 8μm的片状气凝胶。制备的碳气凝胶保持片状结构，在碳化过程中原位形成丰富的孔隙并分布在片层内部。由于其具有减小厚度的准二维（2D）结构，该碳气凝胶作为超级电容器和锂离子电池电极在容量和倍率性能方面表现出显著增强的性能。所提出的方法可能为配置用于储能装置的二维生物质衍生的先进碳材料提供一种简单途径。
