N-doped structures and surface functional groups of reduced graphene oxide and their effect on the electrochemical performance of supercapacitor with organic electrolyte

作者：Li Shin Ming; Yang Shin Yi; Wang Yu Sheng; Tsai Hsiu Ping; Tien Hsi Wen; Hsiao Sheng Tsung; Liao Wei Hao; Chang Chien Liang; Ma Chen Chi M^*; Hu Chi Chang

来源：Journal of Power Sources, 2015, 278: 218-229.

DOI：10.1016/j.jpowsour.2014.12.025

• Reduced graphene oxide
• Supercapacitor
• Nitrogen-doping
• Organic electrolyte
• Ion-diffusion

Nitrogen-doped reduced graphene oxide (N-rGO) has been synthesized using a simple, efficient method combining instant thermal exfoliation and covalent bond transformation from a melamine-graphene oxide mixture. The capacitive performance of N-rGO has been tested in both aqueous (0.5 M H2SO4) and organic (1 M tetraethyl-ammonium tetrafluoroborate (TEABF(4)) in propylene carbonate (PC)) electrolytes, which are compared with those obtained from thermal-reduced graphene oxide (T-rGO) and chemical-reduced graphene oxide (C-rGO). The contributions of scan-rate-independent (double-layer-like) and scan-rate-dependent (pseudo-capacitance-like) capacitance of all reduced graphene oxides in both aqueous and organic electrolytes were evaluated and compared. The results show that relatively rich oxygen-containing functional groups on C-rGO form significant ion-diffusion barrier, resulting in worse electrochemical responses in organic electrolyte. By contrast, the N-doped structures, large surface area, and lower density of oxygen-containing groups make N-rGO become a promising electrode material for organic electric double-layer capacitors (EDLCs). The capacitance rate-retention of N-rGO reaches 71.1% in 1 M TEABF(4)/PC electrolyte when the scan rate is elevated to 200 mVs(-1), demonstrating that N-rGO improves the relatively low-power drawback of EDLCs in organic electrolytes. The specific energy and power of a symmetric N-rGO cell in the organic electrolyte reach 25 Wh kg(-1) and 10 kW kg(-1), respectively.

• 出版日期2015-3-15
• 单位清华大学